Adding upstream version 124.0.1.upstream/124.0.1

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

27 files changed, 7256 insertions, 0 deletions

diff --git a/dom/quota/test/gtest/Common.cpp b/dom/quota/test/gtest/Common.cpp
new file mode 100644
index 0000000000..efbfd94775
--- /dev/null
+++ b/dom/quota/test/gtest/Common.cpp
@@ -0,0 +1,28 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "Common.h"
+
+#include "mozilla/dom/QMResult.h"
+
+namespace mozilla::dom::quota {
+
+#ifdef QM_ERROR_STACKS_ENABLED
+uint64_t DOM_Quota_Test::sExpectedStackId;
+
+// static
+void DOM_Quota_Test::SetUpTestCase() {
+  sExpectedStackId = QMResult().StackId();
+}
+
+// static
+void DOM_Quota_Test::IncreaseExpectedStackId() { sExpectedStackId++; }
+
+// static
+uint64_t DOM_Quota_Test::ExpectedStackId() { return sExpectedStackId; }
+#endif
+
+}  // namespace mozilla::dom::quota
diff --git a/dom/quota/test/gtest/Common.h b/dom/quota/test/gtest/Common.h
new file mode 100644
index 0000000000..eac58bd7fb
--- /dev/null
+++ b/dom/quota/test/gtest/Common.h
@@ -0,0 +1,32 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef DOM_QUOTA_TEST_GTEST_COMMON_H_
+#define DOM_QUOTA_TEST_GTEST_COMMON_H_
+
+#include <cstdint>
+#include "gtest/gtest.h"
+#include "mozilla/dom/quota/Config.h"
+
+namespace mozilla::dom::quota {
+
+class DOM_Quota_Test : public testing::Test {
+#ifdef QM_ERROR_STACKS_ENABLED
+ public:
+  static void SetUpTestCase();
+
+  static void IncreaseExpectedStackId();
+
+  static uint64_t ExpectedStackId();
+
+ private:
+  static uint64_t sExpectedStackId;
+#endif
+};
+
+}  // namespace mozilla::dom::quota
+
+#endif  // DOM_QUOTA_TEST_GTEST_COMMON_H_
diff --git a/dom/quota/test/gtest/PQuotaTest.ipdl b/dom/quota/test/gtest/PQuotaTest.ipdl
new file mode 100644
index 0000000000..3ea2d0c3f9
--- /dev/null
+++ b/dom/quota/test/gtest/PQuotaTest.ipdl
@@ -0,0 +1,27 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+namespace mozilla {
+namespace dom {
+namespace quota {
+
+[ParentProc=any, ChildProc=any]
+sync protocol PQuotaTest {
+ parent:
+  sync Try_Success_CustomErr_QmIpcFail()
+    returns (bool tryDidNotReturn);
+
+  sync Try_Success_CustomErr_IpcFail()
+    returns (bool tryDidNotReturn);
+
+  sync TryInspect_Success_CustomErr_QmIpcFail()
+    returns (bool tryDidNotReturn);
+
+  sync TryInspect_Success_CustomErr_IpcFail()
+    returns (bool tryDidNotReturn);
+};
+
+} // namespace quota
+} // namespace dom
+} // namespace mozilla
diff --git a/dom/quota/test/gtest/QuotaManagerDependencyFixture.cpp b/dom/quota/test/gtest/QuotaManagerDependencyFixture.cpp
new file mode 100644
index 0000000000..2d3fe17705
--- /dev/null
+++ b/dom/quota/test/gtest/QuotaManagerDependencyFixture.cpp
@@ -0,0 +1,263 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "QuotaManagerDependencyFixture.h"
+
+#include "mozIStorageService.h"
+#include "mozStorageCID.h"
+#include "mozilla/BasePrincipal.h"
+#include "mozilla/dom/ScriptSettings.h"
+#include "mozilla/dom/quota/QuotaManagerService.h"
+#include "mozilla/dom/quota/ResultExtensions.h"
+#include "mozilla/gtest/MozAssertions.h"
+#include "mozilla/ipc/BackgroundUtils.h"
+#include "mozilla/ipc/PBackgroundSharedTypes.h"
+#include "nsIPrefBranch.h"
+#include "nsIPrefService.h"
+#include "nsIQuotaCallbacks.h"
+#include "nsIQuotaRequests.h"
+#include "nsIVariant.h"
+#include "nsScriptSecurityManager.h"
+
+namespace mozilla::dom::quota::test {
+
+namespace {
+
+class RequestResolver final : public nsIQuotaCallback {
+ public:
+  RequestResolver() : mDone(false) {}
+
+  bool Done() const { return mDone; }
+
+  NS_DECL_ISUPPORTS
+
+  NS_IMETHOD OnComplete(nsIQuotaRequest* aRequest) override {
+    mDone = true;
+
+    return NS_OK;
+  }
+
+ private:
+  ~RequestResolver() = default;
+
+  bool mDone;
+};
+
+}  // namespace
+
+NS_IMPL_ISUPPORTS(RequestResolver, nsIQuotaCallback)
+
+// static
+void QuotaManagerDependencyFixture::InitializeFixture() {
+  // Some QuotaManagerService methods fail if the testing pref is not set.
+  nsCOMPtr<nsIPrefBranch> prefs = do_GetService(NS_PREFSERVICE_CONTRACTID);
+
+  prefs->SetBoolPref("dom.quotaManager.testing", true);
+
+  // The first initialization of storage service must be done on the main
+  // thread.
+  nsCOMPtr<mozIStorageService> storageService =
+      do_GetService(MOZ_STORAGE_SERVICE_CONTRACTID);
+  ASSERT_TRUE(storageService);
+
+  nsIObserver* observer = QuotaManager::GetObserver();
+  ASSERT_TRUE(observer);
+
+  nsresult rv = observer->Observe(nullptr, "profile-do-change", nullptr);
+  ASSERT_NS_SUCCEEDED(rv);
+
+  ASSERT_NO_FATAL_FAILURE(EnsureQuotaManager());
+
+  QuotaManager* quotaManager = QuotaManager::Get();
+  ASSERT_TRUE(quotaManager);
+
+  ASSERT_TRUE(quotaManager->OwningThread());
+
+  sBackgroundTarget = quotaManager->OwningThread();
+}
+
+// static
+void QuotaManagerDependencyFixture::ShutdownFixture() {
+  nsCOMPtr<nsIPrefBranch> prefs = do_GetService(NS_PREFSERVICE_CONTRACTID);
+
+  prefs->SetBoolPref("dom.quotaManager.testing", false);
+
+  nsIObserver* observer = QuotaManager::GetObserver();
+  ASSERT_TRUE(observer);
+
+  nsresult rv = observer->Observe(nullptr, "profile-before-change-qm", nullptr);
+  ASSERT_NS_SUCCEEDED(rv);
+
+  PerformOnBackgroundThread([]() { QuotaManager::Reset(); });
+
+  sBackgroundTarget = nullptr;
+}
+
+// static
+void QuotaManagerDependencyFixture::InitializeStorage() {
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    bool done = false;
+
+    quotaManager->InitializeStorage()->Then(
+        GetCurrentSerialEventTarget(), __func__,
+        [&done](const BoolPromise::ResolveOrRejectValue& aValue) {
+          done = true;
+        });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+}
+
+// static
+void QuotaManagerDependencyFixture::StorageInitialized(bool* aResult) {
+  ASSERT_TRUE(aResult);
+
+  PerformOnBackgroundThread([aResult]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    bool done = false;
+
+    quotaManager->StorageInitialized()->Then(
+        GetCurrentSerialEventTarget(), __func__,
+        [aResult, &done](const BoolPromise::ResolveOrRejectValue& aValue) {
+          if (aValue.IsResolve()) {
+            *aResult = aValue.ResolveValue();
+          } else {
+            *aResult = false;
+          }
+
+          done = true;
+        });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+}
+
+// static
+void QuotaManagerDependencyFixture::AssertStorageInitialized() {
+  bool result;
+  ASSERT_NO_FATAL_FAILURE(StorageInitialized(&result));
+  ASSERT_TRUE(result);
+}
+
+// static
+void QuotaManagerDependencyFixture::AssertStorageNotInitialized() {
+  bool result;
+  ASSERT_NO_FATAL_FAILURE(StorageInitialized(&result));
+  ASSERT_FALSE(result);
+}
+
+// static
+void QuotaManagerDependencyFixture::ShutdownStorage() {
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    bool done = false;
+
+    quotaManager->ShutdownStorage()->Then(
+        GetCurrentSerialEventTarget(), __func__,
+        [&done](const BoolPromise::ResolveOrRejectValue& aValue) {
+          done = true;
+        });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+}
+
+// static
+void QuotaManagerDependencyFixture::ClearStoragesForOrigin(
+    const OriginMetadata& aOriginMetadata) {
+  PerformOnBackgroundThread([&aOriginMetadata]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    nsCOMPtr<nsIPrincipal> principal =
+        BasePrincipal::CreateContentPrincipal(aOriginMetadata.mOrigin);
+    QM_TRY(MOZ_TO_RESULT(principal), QM_TEST_FAIL);
+
+    mozilla::ipc::PrincipalInfo principalInfo;
+    QM_TRY(MOZ_TO_RESULT(PrincipalToPrincipalInfo(principal, &principalInfo)),
+           QM_TEST_FAIL);
+
+    bool done = false;
+
+    quotaManager
+        ->ClearStoragesForOrigin(/* aPersistenceType */ Nothing(),
+                                 principalInfo, /* aClientType */ Nothing())
+        ->Then(GetCurrentSerialEventTarget(), __func__,
+               [&done](const BoolPromise::ResolveOrRejectValue& aValue) {
+                 done = true;
+               });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+}
+
+// static
+OriginMetadata QuotaManagerDependencyFixture::GetTestOriginMetadata() {
+  return {""_ns,
+          "example.com"_ns,
+          "http://example.com"_ns,
+          "http://example.com"_ns,
+          /* aIsPrivate */ false,
+          PERSISTENCE_TYPE_DEFAULT};
+}
+
+// static
+ClientMetadata QuotaManagerDependencyFixture::GetTestClientMetadata() {
+  return {GetTestOriginMetadata(), Client::SDB};
+}
+
+// static
+OriginMetadata QuotaManagerDependencyFixture::GetOtherTestOriginMetadata() {
+  return {""_ns,
+          "other-example.com"_ns,
+          "http://other-example.com"_ns,
+          "http://other-example.com"_ns,
+          /* aIsPrivate */ false,
+          PERSISTENCE_TYPE_DEFAULT};
+}
+
+// static
+ClientMetadata QuotaManagerDependencyFixture::GetOtherTestClientMetadata() {
+  return {GetOtherTestOriginMetadata(), Client::SDB};
+}
+
+// static
+void QuotaManagerDependencyFixture::EnsureQuotaManager() {
+  AutoJSAPI jsapi;
+
+  bool ok = jsapi.Init(xpc::PrivilegedJunkScope());
+  ASSERT_TRUE(ok);
+
+  nsCOMPtr<nsIQuotaManagerService> qms = QuotaManagerService::GetOrCreate();
+  ASSERT_TRUE(qms);
+
+  // In theory, any nsIQuotaManagerService method which ensures quota manager
+  // on the PBackground thread, could be called here. `StorageName` was chosen
+  // because it doesn't need to do any directory locking or IO.
+  // XXX Consider adding a dedicated nsIQuotaManagerService method for this.
+  nsCOMPtr<nsIQuotaRequest> request;
+  nsresult rv = qms->StorageName(getter_AddRefs(request));
+  ASSERT_NS_SUCCEEDED(rv);
+
+  RefPtr<RequestResolver> resolver = new RequestResolver();
+
+  rv = request->SetCallback(resolver);
+  ASSERT_NS_SUCCEEDED(rv);
+
+  SpinEventLoopUntil("Promise is fulfilled"_ns,
+                     [&resolver]() { return resolver->Done(); });
+}
+
+nsCOMPtr<nsISerialEventTarget> QuotaManagerDependencyFixture::sBackgroundTarget;
+
+}  // namespace mozilla::dom::quota::test
diff --git a/dom/quota/test/gtest/QuotaManagerDependencyFixture.h b/dom/quota/test/gtest/QuotaManagerDependencyFixture.h
new file mode 100644
index 0000000000..639db91c55
--- /dev/null
+++ b/dom/quota/test/gtest/QuotaManagerDependencyFixture.h
@@ -0,0 +1,137 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef DOM_QUOTA_TEST_GTEST_QUOTAMANAGERDEPENDENCYFIXTURE_H_
+#define DOM_QUOTA_TEST_GTEST_QUOTAMANAGERDEPENDENCYFIXTURE_H_
+
+#include "gtest/gtest.h"
+#include "mozilla/MozPromise.h"
+#include "mozilla/SpinEventLoopUntil.h"
+#include "mozilla/dom/quota/DirectoryLock.h"
+#include "mozilla/dom/quota/ForwardDecls.h"
+#include "mozilla/dom/quota/QuotaManager.h"
+
+#define QM_TEST_FAIL [](nsresult) { FAIL(); }
+
+namespace mozilla::dom::quota::test {
+
+class QuotaManagerDependencyFixture : public testing::Test {
+ public:
+  static void InitializeFixture();
+  static void ShutdownFixture();
+
+  static void InitializeStorage();
+  static void StorageInitialized(bool* aResult);
+  static void AssertStorageInitialized();
+  static void AssertStorageNotInitialized();
+  static void ShutdownStorage();
+
+  static void ClearStoragesForOrigin(const OriginMetadata& aOriginMetadata);
+
+  /* Convenience method for tasks which must be called on PBackground thread */
+  template <class Invokable, class... Args>
+  static void PerformOnBackgroundThread(Invokable&& aInvokable,
+                                        Args&&... aArgs) {
+    bool done = false;
+    auto boundTask =
+        // For c++17, bind is cleaner than tuple for parameter pack forwarding
+        // NOLINTNEXTLINE(modernize-avoid-bind)
+        std::bind(std::forward<Invokable>(aInvokable),
+                  std::forward<Args>(aArgs)...);
+    InvokeAsync(BackgroundTargetStrongRef(), __func__,
+                [boundTask = std::move(boundTask)]() mutable {
+                  boundTask();
+                  return BoolPromise::CreateAndResolve(true, __func__);
+                })
+        ->Then(GetCurrentSerialEventTarget(), __func__,
+               [&done](const BoolPromise::ResolveOrRejectValue& /* aValue */) {
+                 done = true;
+               });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  }
+
+  /* Convenience method for tasks which must be executed on IO thread */
+  template <class Invokable, class... Args>
+  static void PerformOnIOThread(Invokable&& aInvokable, Args&&... aArgs) {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    bool done = false;
+    auto boundTask =
+        // For c++17, bind is cleaner than tuple for parameter pack forwarding
+        // NOLINTNEXTLINE(modernize-avoid-bind)
+        std::bind(std::forward<Invokable>(aInvokable),
+                  std::forward<Args>(aArgs)...);
+    InvokeAsync(quotaManager->IOThread(), __func__,
+                [boundTask = std::move(boundTask)]() mutable {
+                  boundTask();
+                  return BoolPromise::CreateAndResolve(true, __func__);
+                })
+        ->Then(GetCurrentSerialEventTarget(), __func__,
+               [&done](const BoolPromise::ResolveOrRejectValue& value) {
+                 done = true;
+               });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  }
+
+  template <class Task>
+  static void PerformClientDirectoryTest(const ClientMetadata& aClientMetadata,
+                                         Task&& aTask) {
+    PerformOnBackgroundThread([clientMetadata = aClientMetadata,
+                               task = std::forward<Task>(aTask)]() mutable {
+      RefPtr<ClientDirectoryLock> directoryLock;
+
+      QuotaManager* quotaManager = QuotaManager::Get();
+      ASSERT_TRUE(quotaManager);
+
+      bool done = false;
+
+      quotaManager->OpenClientDirectory(clientMetadata)
+          ->Then(
+              GetCurrentSerialEventTarget(), __func__,
+              [&directoryLock,
+               &done](RefPtr<ClientDirectoryLock> aResolveValue) {
+                directoryLock = std::move(aResolveValue);
+
+                done = true;
+              },
+              [&done](const nsresult aRejectValue) {
+                ASSERT_TRUE(false);
+
+                done = true;
+              });
+
+      SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+
+      ASSERT_TRUE(directoryLock);
+
+      PerformOnIOThread(std::move(task), directoryLock->Id());
+
+      directoryLock = nullptr;
+    });
+  }
+
+  static const nsCOMPtr<nsISerialEventTarget>& BackgroundTargetStrongRef() {
+    return sBackgroundTarget;
+  }
+
+  static OriginMetadata GetTestOriginMetadata();
+  static ClientMetadata GetTestClientMetadata();
+
+  static OriginMetadata GetOtherTestOriginMetadata();
+  static ClientMetadata GetOtherTestClientMetadata();
+
+ private:
+  static void EnsureQuotaManager();
+
+  static nsCOMPtr<nsISerialEventTarget> sBackgroundTarget;
+};
+
+}  // namespace mozilla::dom::quota::test
+
+#endif  // DOM_QUOTA_TEST_GTEST_QUOTAMANAGERDEPENDENCYFIXTURE_H_
diff --git a/dom/quota/test/gtest/QuotaTestChild.h b/dom/quota/test/gtest/QuotaTestChild.h
new file mode 100644
index 0000000000..d0d87d8267
--- /dev/null
+++ b/dom/quota/test/gtest/QuotaTestChild.h
@@ -0,0 +1,23 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef DOM_QUOTA_TEST_GTEST_QUOTATESTCHILD_H_
+#define DOM_QUOTA_TEST_GTEST_QUOTATESTCHILD_H_
+
+#include "mozilla/dom/quota/PQuotaTestChild.h"
+
+namespace mozilla::dom::quota {
+
+class QuotaTestChild : public PQuotaTestChild {
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(QuotaTestChild, override)
+
+ private:
+  ~QuotaTestChild() = default;
+};
+
+}  // namespace mozilla::dom::quota
+
+#endif  // DOM_QUOTA_TEST_GTEST_QUOTATESTCHILD_H_
diff --git a/dom/quota/test/gtest/QuotaTestParent.h b/dom/quota/test/gtest/QuotaTestParent.h
new file mode 100644
index 0000000000..5ec1e128b3
--- /dev/null
+++ b/dom/quota/test/gtest/QuotaTestParent.h
@@ -0,0 +1,36 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#ifndef DOM_QUOTA_TEST_GTEST_QUOTATESTPARENT_H_
+#define DOM_QUOTA_TEST_GTEST_QUOTATESTPARENT_H_
+
+#include "mozilla/dom/quota/PQuotaTestParent.h"
+
+namespace mozilla::dom::quota {
+
+class QuotaTestParent : public PQuotaTestParent {
+  NS_INLINE_DECL_THREADSAFE_REFCOUNTING(QuotaTestParent, override)
+
+ public:
+  mozilla::ipc::IPCResult RecvTry_Success_CustomErr_QmIpcFail(
+      bool* aTryDidNotReturn);
+
+  mozilla::ipc::IPCResult RecvTry_Success_CustomErr_IpcFail(
+      bool* aTryDidNotReturn);
+
+  mozilla::ipc::IPCResult RecvTryInspect_Success_CustomErr_QmIpcFail(
+      bool* aTryDidNotReturn);
+
+  mozilla::ipc::IPCResult RecvTryInspect_Success_CustomErr_IpcFail(
+      bool* aTryDidNotReturn);
+
+ private:
+  ~QuotaTestParent() = default;
+};
+
+}  // namespace mozilla::dom::quota
+
+#endif  // DOM_QUOTA_TEST_GTEST_QUOTATESTPARENT_H_
diff --git a/dom/quota/test/gtest/TestCheckedUnsafePtr.cpp b/dom/quota/test/gtest/TestCheckedUnsafePtr.cpp
new file mode 100644
index 0000000000..14abb6631d
--- /dev/null
+++ b/dom/quota/test/gtest/TestCheckedUnsafePtr.cpp
@@ -0,0 +1,145 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/quota/CheckedUnsafePtr.h"
+
+#include "gtest/gtest.h"
+
+#include <memory>
+#include <type_traits>
+#include <utility>
+#include "mozilla/fallible.h"
+
+using namespace mozilla;
+
+class NoCheckTestType
+    : public SupportsCheckedUnsafePtr<DoNotCheckCheckedUnsafePtrs> {};
+
+#if __cplusplus < 202002L
+static_assert(std::is_literal_type_v<CheckedUnsafePtr<NoCheckTestType>>);
+#endif
+
+static_assert(
+    std::is_trivially_copy_constructible_v<CheckedUnsafePtr<NoCheckTestType>>);
+static_assert(
+    std::is_trivially_copy_assignable_v<CheckedUnsafePtr<NoCheckTestType>>);
+static_assert(
+    std::is_trivially_move_constructible_v<CheckedUnsafePtr<NoCheckTestType>>);
+static_assert(
+    std::is_trivially_move_assignable_v<CheckedUnsafePtr<NoCheckTestType>>);
+
+class TestCheckingPolicy : public CheckCheckedUnsafePtrs<TestCheckingPolicy> {
+ protected:
+  explicit TestCheckingPolicy(bool& aPassedCheck)
+      : mPassedCheck(aPassedCheck) {}
+
+ private:
+  friend class mozilla::CheckingPolicyAccess;
+  void NotifyCheckFailure() { mPassedCheck = false; }
+
+  bool& mPassedCheck;
+};
+
+struct BasePointee : public SupportsCheckedUnsafePtr<TestCheckingPolicy> {
+  explicit BasePointee(bool& aCheckPassed)
+      : SupportsCheckedUnsafePtr<TestCheckingPolicy>(aCheckPassed) {}
+};
+
+struct DerivedPointee : public BasePointee {
+  using BasePointee::BasePointee;
+};
+
+class CheckedUnsafePtrTest : public ::testing::Test {
+ protected:
+  bool mPassedCheck = true;
+};
+
+TEST_F(CheckedUnsafePtrTest, PointeeWithNoCheckedUnsafePtrs) {
+  { DerivedPointee pointee{mPassedCheck}; }
+  ASSERT_TRUE(mPassedCheck);
+}
+
+template <typename PointerType>
+class TypedCheckedUnsafePtrTest : public CheckedUnsafePtrTest {};
+
+TYPED_TEST_SUITE_P(TypedCheckedUnsafePtrTest);
+
+TYPED_TEST_P(TypedCheckedUnsafePtrTest, PointeeWithOneCheckedUnsafePtr) {
+  {
+    DerivedPointee pointee{this->mPassedCheck};
+    CheckedUnsafePtr<TypeParam> ptr = &pointee;
+  }
+  ASSERT_TRUE(this->mPassedCheck);
+}
+
+TYPED_TEST_P(TypedCheckedUnsafePtrTest, CheckedUnsafePtrCopyConstructed) {
+  {
+    DerivedPointee pointee{this->mPassedCheck};
+    CheckedUnsafePtr<TypeParam> ptr1 = &pointee;
+    CheckedUnsafePtr<TypeParam> ptr2 = ptr1;
+  }
+  ASSERT_TRUE(this->mPassedCheck);
+}
+
+TYPED_TEST_P(TypedCheckedUnsafePtrTest, CheckedUnsafePtrCopyAssigned) {
+  {
+    DerivedPointee pointee{this->mPassedCheck};
+    CheckedUnsafePtr<TypeParam> ptr1 = &pointee;
+    CheckedUnsafePtr<TypeParam> ptr2;
+    ptr2 = ptr1;
+  }
+  ASSERT_TRUE(this->mPassedCheck);
+}
+
+TYPED_TEST_P(TypedCheckedUnsafePtrTest,
+             PointeeWithOneDanglingCheckedUnsafePtr) {
+  [this]() -> CheckedUnsafePtr<TypeParam> {
+    DerivedPointee pointee{this->mPassedCheck};
+    return &pointee;
+  }();
+  ASSERT_FALSE(this->mPassedCheck);
+}
+
+TYPED_TEST_P(TypedCheckedUnsafePtrTest,
+             PointeeWithOneCopiedDanglingCheckedUnsafePtr) {
+  const auto dangling1 = [this]() -> CheckedUnsafePtr<DerivedPointee> {
+    DerivedPointee pointee{this->mPassedCheck};
+    return &pointee;
+  }();
+  EXPECT_FALSE(this->mPassedCheck);
+
+  // With AddressSanitizer we would hopefully detect if the copy constructor
+  // tries to add dangling2 to the now-gone pointee's unsafe pointer array. No
+  // promises though, since it might be optimized away.
+  CheckedUnsafePtr<TypeParam> dangling2{dangling1};
+  ASSERT_TRUE(dangling2);
+}
+
+TYPED_TEST_P(TypedCheckedUnsafePtrTest,
+             PointeeWithOneCopyAssignedDanglingCheckedUnsafePtr) {
+  const auto dangling1 = [this]() -> CheckedUnsafePtr<DerivedPointee> {
+    DerivedPointee pointee{this->mPassedCheck};
+    return &pointee;
+  }();
+  EXPECT_FALSE(this->mPassedCheck);
+
+  // With AddressSanitizer we would hopefully detect if the assignment tries to
+  // add dangling2 to the now-gone pointee's unsafe pointer array. No promises
+  // though, since it might be optimized away.
+  CheckedUnsafePtr<TypeParam> dangling2;
+  dangling2 = dangling1;
+  ASSERT_TRUE(dangling2);
+}
+
+REGISTER_TYPED_TEST_SUITE_P(TypedCheckedUnsafePtrTest,
+                            PointeeWithOneCheckedUnsafePtr,
+                            CheckedUnsafePtrCopyConstructed,
+                            CheckedUnsafePtrCopyAssigned,
+                            PointeeWithOneDanglingCheckedUnsafePtr,
+                            PointeeWithOneCopiedDanglingCheckedUnsafePtr,
+                            PointeeWithOneCopyAssignedDanglingCheckedUnsafePtr);
+
+using BothTypes = ::testing::Types<BasePointee, DerivedPointee>;
+INSTANTIATE_TYPED_TEST_SUITE_P(InstantiationOf, TypedCheckedUnsafePtrTest,
+                               BothTypes);
diff --git a/dom/quota/test/gtest/TestClientUsageArray.cpp b/dom/quota/test/gtest/TestClientUsageArray.cpp
new file mode 100644
index 0000000000..f5db984ccd
--- /dev/null
+++ b/dom/quota/test/gtest/TestClientUsageArray.cpp
@@ -0,0 +1,17 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "ClientUsageArray.h"
+#include "gtest/gtest.h"
+
+using namespace mozilla::dom::quota;
+
+TEST(DOM_Quota_ClientUsageArray, Deserialize)
+{
+  ClientUsageArray clientUsages;
+  nsresult rv = clientUsages.Deserialize("I872215 C8404073805 L161709"_ns);
+  ASSERT_EQ(rv, NS_OK);
+}
diff --git a/dom/quota/test/gtest/TestEncryptedStream.cpp b/dom/quota/test/gtest/TestEncryptedStream.cpp
new file mode 100644
index 0000000000..8937b0c4e7
--- /dev/null
+++ b/dom/quota/test/gtest/TestEncryptedStream.cpp
@@ -0,0 +1,804 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gtest/gtest.h"
+
+#include <algorithm>
+#include <cstdint>
+#include <cstdlib>
+#include <new>
+#include <numeric>
+#include <ostream>
+#include <string>
+#include <type_traits>
+#include <utility>
+#include <vector>
+#include "ErrorList.h"
+#include "mozilla/AlreadyAddRefed.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/Attributes.h"
+#include "mozilla/FixedBufferOutputStream.h"
+#include "mozilla/NotNull.h"
+#include "mozilla/RefPtr.h"
+#include "mozilla/Span.h"
+#include "mozilla/UniquePtr.h"
+#include "mozilla/dom/SafeRefPtr.h"
+#include "mozilla/dom/quota/DecryptingInputStream_impl.h"
+#include "mozilla/dom/quota/DummyCipherStrategy.h"
+#include "mozilla/dom/quota/EncryptedBlock.h"
+#include "mozilla/dom/quota/EncryptingOutputStream_impl.h"
+#include "mozilla/dom/quota/NSSCipherStrategy.h"
+#include "mozilla/fallible.h"
+#include "nsCOMPtr.h"
+#include "nsError.h"
+#include "nsICloneableInputStream.h"
+#include "nsIInputStream.h"
+#include "nsIOutputStream.h"
+#include "nsISeekableStream.h"
+#include "nsISupports.h"
+#include "nsITellableStream.h"
+#include "nsStreamUtils.h"
+#include "nsString.h"
+#include "nsStringFwd.h"
+#include "nsTArray.h"
+#include "nscore.h"
+#include "nss.h"
+
+namespace mozilla::dom::quota {
+
+// Similar to ArrayBufferInputStream from netwerk/base/ArrayBufferInputStream.h,
+// but this is initialized from a Span on construction, rather than lazily from
+// a JS ArrayBuffer.
+class ArrayBufferInputStream : public nsIInputStream,
+                               public nsISeekableStream,
+                               public nsICloneableInputStream {
+ public:
+  explicit ArrayBufferInputStream(mozilla::Span<const uint8_t> aData);
+
+  NS_DECL_THREADSAFE_ISUPPORTS
+  NS_DECL_NSIINPUTSTREAM
+  NS_DECL_NSITELLABLESTREAM
+  NS_DECL_NSISEEKABLESTREAM
+  NS_DECL_NSICLONEABLEINPUTSTREAM
+
+ private:
+  virtual ~ArrayBufferInputStream() = default;
+
+  mozilla::UniquePtr<char[]> mArrayBuffer;
+  uint32_t mBufferLength;
+  uint32_t mPos;
+  bool mClosed;
+};
+
+NS_IMPL_ADDREF(ArrayBufferInputStream);
+NS_IMPL_RELEASE(ArrayBufferInputStream);
+
+NS_INTERFACE_MAP_BEGIN(ArrayBufferInputStream)
+  NS_INTERFACE_MAP_ENTRY(nsIInputStream)
+  NS_INTERFACE_MAP_ENTRY(nsISeekableStream)
+  NS_INTERFACE_MAP_ENTRY(nsICloneableInputStream)
+  NS_INTERFACE_MAP_ENTRY_AMBIGUOUS(nsISupports, nsIInputStream)
+NS_INTERFACE_MAP_END
+
+ArrayBufferInputStream::ArrayBufferInputStream(
+    mozilla::Span<const uint8_t> aData)
+    : mArrayBuffer(MakeUnique<char[]>(aData.Length())),
+      mBufferLength(aData.Length()),
+      mPos(0),
+      mClosed(false) {
+  std::copy(aData.cbegin(), aData.cend(), mArrayBuffer.get());
+}
+
+NS_IMETHODIMP
+ArrayBufferInputStream::Close() {
+  mClosed = true;
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ArrayBufferInputStream::Available(uint64_t* aCount) {
+  if (mClosed) {
+    return NS_BASE_STREAM_CLOSED;
+  }
+
+  if (mArrayBuffer) {
+    *aCount = mBufferLength ? mBufferLength - mPos : 0;
+  } else {
+    *aCount = 0;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ArrayBufferInputStream::StreamStatus() {
+  return mClosed ? NS_BASE_STREAM_CLOSED : NS_OK;
+}
+
+NS_IMETHODIMP
+ArrayBufferInputStream::Read(char* aBuf, uint32_t aCount,
+                             uint32_t* aReadCount) {
+  return ReadSegments(NS_CopySegmentToBuffer, aBuf, aCount, aReadCount);
+}
+
+NS_IMETHODIMP
+ArrayBufferInputStream::ReadSegments(nsWriteSegmentFun writer, void* closure,
+                                     uint32_t aCount, uint32_t* result) {
+  MOZ_ASSERT(result, "null ptr");
+  MOZ_ASSERT(mBufferLength >= mPos, "bad stream state");
+
+  if (mClosed) {
+    return NS_BASE_STREAM_CLOSED;
+  }
+
+  MOZ_ASSERT(mArrayBuffer || (mPos == mBufferLength),
+             "stream inited incorrectly");
+
+  *result = 0;
+  while (mPos < mBufferLength) {
+    uint32_t remaining = mBufferLength - mPos;
+    MOZ_ASSERT(mArrayBuffer);
+
+    uint32_t count = std::min(aCount, remaining);
+    if (count == 0) {
+      break;
+    }
+
+    uint32_t written;
+    nsresult rv = writer(this, closure, &mArrayBuffer[0] + mPos, *result, count,
+                         &written);
+    if (NS_FAILED(rv)) {
+      // InputStreams do not propagate errors to caller.
+      return NS_OK;
+    }
+
+    MOZ_ASSERT(written <= count,
+               "writer should not write more than we asked it to write");
+    mPos += written;
+    *result += written;
+    aCount -= written;
+  }
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP
+ArrayBufferInputStream::IsNonBlocking(bool* aNonBlocking) {
+  // Actually, the stream never blocks, but we lie about it because of the
+  // assumptions in DecryptingInputStream.
+  *aNonBlocking = false;
+  return NS_OK;
+}
+
+NS_IMETHODIMP ArrayBufferInputStream::Tell(int64_t* const aRetval) {
+  MOZ_ASSERT(aRetval);
+
+  *aRetval = mPos;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP ArrayBufferInputStream::Seek(const int32_t aWhence,
+                                           const int64_t aOffset) {
+  // XXX This is not safe. it's hard to use CheckedInt here, though. As long as
+  // the class is only used for testing purposes, that's probably fine.
+
+  int32_t newPos = mPos;
+  switch (aWhence) {
+    case NS_SEEK_SET:
+      newPos = aOffset;
+      break;
+    case NS_SEEK_CUR:
+      newPos += aOffset;
+      break;
+    case NS_SEEK_END:
+      newPos = mBufferLength;
+      newPos += aOffset;
+      break;
+    default:
+      return NS_ERROR_ILLEGAL_VALUE;
+  }
+  if (newPos < 0 || static_cast<uint32_t>(newPos) > mBufferLength) {
+    return NS_ERROR_ILLEGAL_VALUE;
+  }
+  mPos = newPos;
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP ArrayBufferInputStream::SetEOF() {
+  // Truncating is not supported on a read-only stream.
+  return NS_ERROR_NOT_IMPLEMENTED;
+}
+
+NS_IMETHODIMP ArrayBufferInputStream::GetCloneable(bool* aCloneable) {
+  *aCloneable = true;
+  return NS_OK;
+}
+
+NS_IMETHODIMP ArrayBufferInputStream::Clone(nsIInputStream** _retval) {
+  *_retval = MakeAndAddRef<ArrayBufferInputStream>(
+                 AsBytes(Span{mArrayBuffer.get(), mBufferLength}))
+                 .take();
+
+  return NS_OK;
+}
+}  // namespace mozilla::dom::quota
+
+using namespace mozilla;
+using namespace mozilla::dom::quota;
+
+class DOM_Quota_EncryptedStream : public ::testing::Test {
+ public:
+  static void SetUpTestCase() {
+    // Do this only once, do not tear it down per test case.
+    if (!sNssContext) {
+      sNssContext.reset(
+          NSS_InitContext("", "", "", "", nullptr,
+                          NSS_INIT_READONLY | NSS_INIT_NOCERTDB |
+                              NSS_INIT_NOMODDB | NSS_INIT_FORCEOPEN |
+                              NSS_INIT_OPTIMIZESPACE | NSS_INIT_NOROOTINIT));
+    }
+  }
+
+  static void TearDownTestCase() { sNssContext = nullptr; }
+
+ private:
+  struct NSSInitContextDeleter {
+    void operator()(NSSInitContext* p) { NSS_ShutdownContext(p); }
+  };
+  inline static std::unique_ptr<NSSInitContext, NSSInitContextDeleter>
+      sNssContext;
+};
+
+enum struct FlushMode { AfterEachChunk, Never };
+enum struct ChunkSize { SingleByte, Unaligned, DataSize };
+
+using PackedTestParams =
+    std::tuple<size_t, ChunkSize, ChunkSize, size_t, FlushMode>;
+
+static size_t EffectiveChunkSize(const ChunkSize aChunkSize,
+                                 const size_t aDataSize) {
+  switch (aChunkSize) {
+    case ChunkSize::SingleByte:
+      return 1;
+    case ChunkSize::Unaligned:
+      return 17;
+    case ChunkSize::DataSize:
+      return aDataSize;
+  }
+  MOZ_CRASH("Unknown ChunkSize");
+}
+
+struct TestParams {
+  MOZ_IMPLICIT constexpr TestParams(const PackedTestParams& aPackedParams)
+      : mDataSize(std::get<0>(aPackedParams)),
+        mWriteChunkSize(std::get<1>(aPackedParams)),
+        mReadChunkSize(std::get<2>(aPackedParams)),
+        mBlockSize(std::get<3>(aPackedParams)),
+        mFlushMode(std::get<4>(aPackedParams)) {}
+
+  constexpr size_t DataSize() const { return mDataSize; }
+
+  size_t EffectiveWriteChunkSize() const {
+    return EffectiveChunkSize(mWriteChunkSize, mDataSize);
+  }
+
+  size_t EffectiveReadChunkSize() const {
+    return EffectiveChunkSize(mReadChunkSize, mDataSize);
+  }
+
+  constexpr size_t BlockSize() const { return mBlockSize; }
+
+  constexpr enum FlushMode FlushMode() const { return mFlushMode; }
+
+ private:
+  size_t mDataSize;
+
+  ChunkSize mWriteChunkSize;
+  ChunkSize mReadChunkSize;
+
+  size_t mBlockSize;
+  enum FlushMode mFlushMode;
+};
+
+std::string TestParamToString(
+    const testing::TestParamInfo<PackedTestParams>& aTestParams) {
+  const TestParams& testParams = aTestParams.param;
+
+  static constexpr char kSeparator[] = "_";
+
+  std::stringstream ss;
+  ss << "data" << testParams.DataSize() << kSeparator << "writechunk"
+     << testParams.EffectiveWriteChunkSize() << kSeparator << "readchunk"
+     << testParams.EffectiveReadChunkSize() << kSeparator << "block"
+     << testParams.BlockSize() << kSeparator;
+  switch (testParams.FlushMode()) {
+    case FlushMode::Never:
+      ss << "FlushNever";
+      break;
+    case FlushMode::AfterEachChunk:
+      ss << "FlushAfterEachChunk";
+      break;
+  };
+  return ss.str();
+}
+
+class ParametrizedCryptTest
+    : public DOM_Quota_EncryptedStream,
+      public testing::WithParamInterface<PackedTestParams> {};
+
+static auto MakeTestData(const size_t aDataSize) {
+  auto data = nsTArray<uint8_t>();
+  data.SetLength(aDataSize);
+  std::iota(data.begin(), data.end(), 0);
+  return data;
+}
+
+template <typename CipherStrategy>
+static void WriteTestData(nsCOMPtr<nsIOutputStream>&& aBaseOutputStream,
+                          const Span<const uint8_t> aData,
+                          const size_t aWriteChunkSize, const size_t aBlockSize,
+                          const typename CipherStrategy::KeyType& aKey,
+                          const FlushMode aFlushMode) {
+  auto outStream = MakeSafeRefPtr<EncryptingOutputStream<CipherStrategy>>(
+      std::move(aBaseOutputStream), aBlockSize, aKey);
+
+  for (auto remaining = aData; !remaining.IsEmpty();) {
+    auto [currentChunk, newRemaining] =
+        remaining.SplitAt(std::min(aWriteChunkSize, remaining.Length()));
+    remaining = newRemaining;
+
+    uint32_t written;
+    EXPECT_EQ(NS_OK, outStream->Write(
+                         reinterpret_cast<const char*>(currentChunk.Elements()),
+                         currentChunk.Length(), &written));
+    EXPECT_EQ(currentChunk.Length(), written);
+
+    if (aFlushMode == FlushMode::AfterEachChunk) {
+      outStream->Flush();
+    }
+  }
+
+  // Close explicitly so we can check the result.
+  EXPECT_EQ(NS_OK, outStream->Close());
+}
+
+template <typename CipherStrategy>
+static void NoExtraChecks(DecryptingInputStream<CipherStrategy>& aInputStream,
+                          Span<const uint8_t> aExpectedData,
+                          Span<const uint8_t> aRemainder) {}
+
+template <typename CipherStrategy,
+          typename ExtraChecks = decltype(NoExtraChecks<CipherStrategy>)>
+static void ReadTestData(
+    DecryptingInputStream<CipherStrategy>& aDecryptingInputStream,
+    const Span<const uint8_t> aExpectedData, const size_t aReadChunkSize,
+    const ExtraChecks& aExtraChecks = NoExtraChecks<CipherStrategy>) {
+  auto readData = nsTArray<uint8_t>();
+  readData.SetLength(aReadChunkSize);
+  for (auto remainder = aExpectedData; !remainder.IsEmpty();) {
+    auto [currentExpected, newExpectedRemainder] =
+        remainder.SplitAt(std::min(aReadChunkSize, remainder.Length()));
+    remainder = newExpectedRemainder;
+
+    uint32_t read;
+    EXPECT_EQ(NS_OK, aDecryptingInputStream.Read(
+                         reinterpret_cast<char*>(readData.Elements()),
+                         currentExpected.Length(), &read));
+    EXPECT_EQ(currentExpected.Length(), read);
+    EXPECT_EQ(currentExpected,
+              Span{readData}.First(currentExpected.Length()).AsConst());
+
+    aExtraChecks(aDecryptingInputStream, aExpectedData, remainder);
+  }
+
+  // Expect EOF.
+  uint32_t read;
+  EXPECT_EQ(NS_OK, aDecryptingInputStream.Read(
+                       reinterpret_cast<char*>(readData.Elements()),
+                       readData.Length(), &read));
+  EXPECT_EQ(0u, read);
+}
+
+template <typename CipherStrategy,
+          typename ExtraChecks = decltype(NoExtraChecks<CipherStrategy>)>
+static auto ReadTestData(
+    MovingNotNull<nsCOMPtr<nsIInputStream>>&& aBaseInputStream,
+    const Span<const uint8_t> aExpectedData, const size_t aReadChunkSize,
+    const size_t aBlockSize, const typename CipherStrategy::KeyType& aKey,
+    const ExtraChecks& aExtraChecks = NoExtraChecks<CipherStrategy>) {
+  auto inStream = MakeSafeRefPtr<DecryptingInputStream<CipherStrategy>>(
+      std::move(aBaseInputStream), aBlockSize, aKey);
+
+  ReadTestData(*inStream, aExpectedData, aReadChunkSize, aExtraChecks);
+
+  return inStream;
+}
+
+// XXX Change to return the buffer instead.
+template <typename CipherStrategy,
+          typename ExtraChecks = decltype(NoExtraChecks<CipherStrategy>)>
+static RefPtr<FixedBufferOutputStream> DoRoundtripTest(
+    const size_t aDataSize, const size_t aWriteChunkSize,
+    const size_t aReadChunkSize, const size_t aBlockSize,
+    const typename CipherStrategy::KeyType& aKey, const FlushMode aFlushMode,
+    const ExtraChecks& aExtraChecks = NoExtraChecks<CipherStrategy>) {
+  // XXX Add deduction guide for RefPtr from already_AddRefed
+  const auto baseOutputStream = WrapNotNull(
+      RefPtr<FixedBufferOutputStream>{FixedBufferOutputStream::Create(2048)});
+
+  const auto data = MakeTestData(aDataSize);
+
+  WriteTestData<CipherStrategy>(
+      nsCOMPtr<nsIOutputStream>{baseOutputStream.get()}, Span{data},
+      aWriteChunkSize, aBlockSize, aKey, aFlushMode);
+
+  const auto baseInputStream =
+      MakeRefPtr<ArrayBufferInputStream>(baseOutputStream->WrittenData());
+
+  ReadTestData<CipherStrategy>(
+      WrapNotNull(nsCOMPtr<nsIInputStream>{baseInputStream}), Span{data},
+      aReadChunkSize, aBlockSize, aKey, aExtraChecks);
+
+  return baseOutputStream;
+}
+
+TEST_P(ParametrizedCryptTest, NSSCipherStrategy) {
+  using CipherStrategy = NSSCipherStrategy;
+  const TestParams& testParams = GetParam();
+
+  auto keyOrErr = CipherStrategy::GenerateKey();
+  ASSERT_FALSE(keyOrErr.isErr());
+
+  DoRoundtripTest<CipherStrategy>(
+      testParams.DataSize(), testParams.EffectiveWriteChunkSize(),
+      testParams.EffectiveReadChunkSize(), testParams.BlockSize(),
+      keyOrErr.unwrap(), testParams.FlushMode());
+}
+
+TEST_P(ParametrizedCryptTest, DummyCipherStrategy_CheckOutput) {
+  using CipherStrategy = DummyCipherStrategy;
+  const TestParams& testParams = GetParam();
+
+  const auto encryptedDataStream = DoRoundtripTest<CipherStrategy>(
+      testParams.DataSize(), testParams.EffectiveWriteChunkSize(),
+      testParams.EffectiveReadChunkSize(), testParams.BlockSize(),
+      CipherStrategy::KeyType{}, testParams.FlushMode());
+
+  if (HasFailure()) {
+    return;
+  }
+
+  const auto encryptedData = encryptedDataStream->WrittenData();
+  const auto encryptedDataSpan = AsBytes(Span(encryptedData));
+
+  const auto plainTestData = MakeTestData(testParams.DataSize());
+  auto encryptedBlock = EncryptedBlock<DummyCipherStrategy::BlockPrefixLength,
+                                       DummyCipherStrategy::BasicBlockSize>{
+      testParams.BlockSize(),
+  };
+  for (auto [encryptedRemainder, plainRemainder] =
+           std::pair(encryptedDataSpan, Span(plainTestData));
+       !encryptedRemainder.IsEmpty();) {
+    const auto [currentBlock, newEncryptedRemainder] =
+        encryptedRemainder.SplitAt(testParams.BlockSize());
+    encryptedRemainder = newEncryptedRemainder;
+
+    std::copy(currentBlock.cbegin(), currentBlock.cend(),
+              encryptedBlock.MutableWholeBlock().begin());
+
+    ASSERT_FALSE(plainRemainder.IsEmpty());
+    const auto [currentPlain, newPlainRemainder] =
+        plainRemainder.SplitAt(encryptedBlock.ActualPayloadLength());
+    plainRemainder = newPlainRemainder;
+
+    const auto pseudoIV = encryptedBlock.CipherPrefix();
+    const auto payload = encryptedBlock.Payload();
+
+    EXPECT_EQ(Span(DummyCipherStrategy::MakeBlockPrefix()), pseudoIV);
+
+    auto untransformedPayload = nsTArray<uint8_t>();
+    untransformedPayload.SetLength(testParams.BlockSize());
+    DummyCipherStrategy::DummyTransform(payload, untransformedPayload);
+
+    EXPECT_EQ(
+        currentPlain,
+        Span(untransformedPayload).AsConst().First(currentPlain.Length()));
+  }
+}
+
+TEST_P(ParametrizedCryptTest, DummyCipherStrategy_Tell) {
+  using CipherStrategy = DummyCipherStrategy;
+  const TestParams& testParams = GetParam();
+
+  DoRoundtripTest<CipherStrategy>(
+      testParams.DataSize(), testParams.EffectiveWriteChunkSize(),
+      testParams.EffectiveReadChunkSize(), testParams.BlockSize(),
+      CipherStrategy::KeyType{}, testParams.FlushMode(),
+      [](auto& inStream, Span<const uint8_t> expectedData,
+         Span<const uint8_t> remainder) {
+        // Check that Tell tells the right position.
+        int64_t pos;
+        EXPECT_EQ(NS_OK, inStream.Tell(&pos));
+        EXPECT_EQ(expectedData.Length() - remainder.Length(),
+                  static_cast<uint64_t>(pos));
+      });
+}
+
+TEST_P(ParametrizedCryptTest, DummyCipherStrategy_Available) {
+  using CipherStrategy = DummyCipherStrategy;
+  const TestParams& testParams = GetParam();
+
+  DoRoundtripTest<CipherStrategy>(
+      testParams.DataSize(), testParams.EffectiveWriteChunkSize(),
+      testParams.EffectiveReadChunkSize(), testParams.BlockSize(),
+      CipherStrategy::KeyType{}, testParams.FlushMode(),
+      [](auto& inStream, Span<const uint8_t> expectedData,
+         Span<const uint8_t> remainder) {
+        // Check that Available tells the right remainder.
+        uint64_t available;
+        EXPECT_EQ(NS_OK, inStream.Available(&available));
+        EXPECT_EQ(remainder.Length(), available);
+      });
+}
+
+TEST_P(ParametrizedCryptTest, DummyCipherStrategy_Clone) {
+  using CipherStrategy = DummyCipherStrategy;
+  const TestParams& testParams = GetParam();
+
+  // XXX Add deduction guide for RefPtr from already_AddRefed
+  const auto baseOutputStream = WrapNotNull(
+      RefPtr<FixedBufferOutputStream>{FixedBufferOutputStream::Create(2048)});
+
+  const auto data = MakeTestData(testParams.DataSize());
+
+  WriteTestData<CipherStrategy>(
+      nsCOMPtr<nsIOutputStream>{baseOutputStream.get()}, Span{data},
+      testParams.EffectiveWriteChunkSize(), testParams.BlockSize(),
+      CipherStrategy::KeyType{}, testParams.FlushMode());
+
+  const auto baseInputStream =
+      MakeRefPtr<ArrayBufferInputStream>(baseOutputStream->WrittenData());
+
+  const auto inStream = ReadTestData<CipherStrategy>(
+      WrapNotNull(nsCOMPtr<nsIInputStream>{baseInputStream}), Span{data},
+      testParams.EffectiveReadChunkSize(), testParams.BlockSize(),
+      CipherStrategy::KeyType{});
+
+  nsCOMPtr<nsIInputStream> clonedInputStream;
+  EXPECT_EQ(NS_OK, inStream->Clone(getter_AddRefs(clonedInputStream)));
+
+  ReadTestData(
+      static_cast<DecryptingInputStream<CipherStrategy>&>(*clonedInputStream),
+      Span{data}, testParams.EffectiveReadChunkSize());
+}
+
+// XXX This test is actually only parametrized on the block size.
+TEST_P(ParametrizedCryptTest, DummyCipherStrategy_IncompleteBlock) {
+  using CipherStrategy = DummyCipherStrategy;
+  const TestParams& testParams = GetParam();
+
+  // Provide half a block, content doesn't matter.
+  nsTArray<uint8_t> data;
+  data.SetLength(testParams.BlockSize() / 2);
+
+  const auto baseInputStream = MakeRefPtr<ArrayBufferInputStream>(data);
+
+  const auto inStream = MakeSafeRefPtr<DecryptingInputStream<CipherStrategy>>(
+      WrapNotNull(nsCOMPtr<nsIInputStream>{baseInputStream}),
+      testParams.BlockSize(), CipherStrategy::KeyType{});
+
+  nsTArray<uint8_t> readData;
+  readData.SetLength(testParams.BlockSize());
+  uint32_t read;
+  EXPECT_EQ(NS_ERROR_CORRUPTED_CONTENT,
+            inStream->Read(reinterpret_cast<char*>(readData.Elements()),
+                           readData.Length(), &read));
+}
+
+TEST_P(ParametrizedCryptTest, zeroInitializedEncryptedBlock) {
+  const TestParams& testParams = GetParam();
+
+  using EncryptedBlock = EncryptedBlock<DummyCipherStrategy::BlockPrefixLength,
+                                        DummyCipherStrategy::BasicBlockSize>;
+
+  EncryptedBlock encryptedBlock{testParams.BlockSize()};
+  auto firstBlock =
+      encryptedBlock.WholeBlock().First<DummyCipherStrategy::BasicBlockSize>();
+  auto unusedBytesInFirstBlock = firstBlock.from(sizeof(uint16_t));
+
+  EXPECT_TRUE(std::all_of(unusedBytesInFirstBlock.begin(),
+                          unusedBytesInFirstBlock.end(),
+                          [](const auto& e) { return 0ul == e; }));
+}
+
+enum struct SeekOffset {
+  Zero,
+  MinusHalfDataSize,
+  PlusHalfDataSize,
+  PlusDataSize,
+  MinusDataSize
+};
+using SeekOp = std::pair<int32_t, SeekOffset>;
+
+using PackedSeekTestParams = std::tuple<size_t, size_t, std::vector<SeekOp>>;
+
+struct SeekTestParams {
+  size_t mDataSize;
+  size_t mBlockSize;
+  std::vector<SeekOp> mSeekOps;
+
+  MOZ_IMPLICIT SeekTestParams(const PackedSeekTestParams& aPackedParams)
+      : mDataSize(std::get<0>(aPackedParams)),
+        mBlockSize(std::get<1>(aPackedParams)),
+        mSeekOps(std::get<2>(aPackedParams)) {}
+};
+
+std::string SeekTestParamToString(
+    const testing::TestParamInfo<PackedSeekTestParams>& aTestParams) {
+  const SeekTestParams& testParams = aTestParams.param;
+
+  static constexpr char kSeparator[] = "_";
+
+  std::stringstream ss;
+  ss << "data" << testParams.mDataSize << kSeparator << "writechunk"
+     << testParams.mBlockSize << kSeparator;
+  for (const auto& seekOp : testParams.mSeekOps) {
+    switch (seekOp.first) {
+      case nsISeekableStream::NS_SEEK_SET:
+        ss << "Set";
+        break;
+      case nsISeekableStream::NS_SEEK_CUR:
+        ss << "Cur";
+        break;
+      case nsISeekableStream::NS_SEEK_END:
+        ss << "End";
+        break;
+    };
+    switch (seekOp.second) {
+      case SeekOffset::Zero:
+        ss << "Zero";
+        break;
+      case SeekOffset::MinusHalfDataSize:
+        ss << "MinusHalfDataSize";
+        break;
+      case SeekOffset::PlusHalfDataSize:
+        ss << "PlusHalfDataSize";
+        break;
+      case SeekOffset::MinusDataSize:
+        ss << "MinusDataSize";
+        break;
+      case SeekOffset::PlusDataSize:
+        ss << "PlusDataSize";
+        break;
+    };
+  }
+  return ss.str();
+}
+
+class ParametrizedSeekCryptTest
+    : public DOM_Quota_EncryptedStream,
+      public testing::WithParamInterface<PackedSeekTestParams> {};
+
+TEST_P(ParametrizedSeekCryptTest, DummyCipherStrategy_Seek) {
+  using CipherStrategy = DummyCipherStrategy;
+  const SeekTestParams& testParams = GetParam();
+
+  const auto baseOutputStream = WrapNotNull(
+      RefPtr<FixedBufferOutputStream>{FixedBufferOutputStream::Create(2048)});
+
+  const auto data = MakeTestData(testParams.mDataSize);
+
+  WriteTestData<CipherStrategy>(
+      nsCOMPtr<nsIOutputStream>{baseOutputStream.get()}, Span{data},
+      testParams.mDataSize, testParams.mBlockSize, CipherStrategy::KeyType{},
+      FlushMode::Never);
+
+  const auto baseInputStream =
+      MakeRefPtr<ArrayBufferInputStream>(baseOutputStream->WrittenData());
+
+  const auto inStream = MakeSafeRefPtr<DecryptingInputStream<CipherStrategy>>(
+      WrapNotNull(nsCOMPtr<nsIInputStream>{baseInputStream}),
+      testParams.mBlockSize, CipherStrategy::KeyType{});
+
+  uint32_t accumulatedOffset = 0;
+  for (const auto& seekOp : testParams.mSeekOps) {
+    const auto offset = [offsetKind = seekOp.second,
+                         dataSize = testParams.mDataSize]() -> int64_t {
+      switch (offsetKind) {
+        case SeekOffset::Zero:
+          return 0;
+        case SeekOffset::MinusHalfDataSize:
+          return -static_cast<int64_t>(dataSize) / 2;
+        case SeekOffset::PlusHalfDataSize:
+          return dataSize / 2;
+        case SeekOffset::MinusDataSize:
+          return -static_cast<int64_t>(dataSize);
+        case SeekOffset::PlusDataSize:
+          return dataSize;
+      }
+      MOZ_CRASH("Unknown SeekOffset");
+    }();
+    switch (seekOp.first) {
+      case nsISeekableStream::NS_SEEK_SET:
+        accumulatedOffset = offset;
+        break;
+      case nsISeekableStream::NS_SEEK_CUR:
+        accumulatedOffset += offset;
+        break;
+      case nsISeekableStream::NS_SEEK_END:
+        accumulatedOffset = testParams.mDataSize + offset;
+        break;
+    }
+    EXPECT_EQ(NS_OK, inStream->Seek(seekOp.first, offset));
+  }
+
+  {
+    int64_t actualOffset;
+    EXPECT_EQ(NS_OK, inStream->Tell(&actualOffset));
+
+    EXPECT_EQ(actualOffset, accumulatedOffset);
+  }
+
+  auto readData = nsTArray<uint8_t>();
+  readData.SetLength(data.Length());
+  uint32_t read;
+  EXPECT_EQ(NS_OK, inStream->Read(reinterpret_cast<char*>(readData.Elements()),
+                                  readData.Length(), &read));
+  // XXX Or should 'read' indicate the actual number of bytes read,
+  // including the encryption overhead?
+  EXPECT_EQ(testParams.mDataSize - accumulatedOffset, read);
+  EXPECT_EQ(Span{data}.SplitAt(accumulatedOffset).second,
+            Span{readData}.First(read).AsConst());
+}
+
+INSTANTIATE_TEST_SUITE_P(
+    DOM_Quota_EncryptedStream_Parametrized, ParametrizedCryptTest,
+    testing::Combine(
+        /* dataSize */ testing::Values(0u, 16u, 256u, 512u, 513u),
+        /* writeChunkSize */
+        testing::Values(ChunkSize::SingleByte, ChunkSize::Unaligned,
+                        ChunkSize::DataSize),
+        /* readChunkSize */
+        testing::Values(ChunkSize::SingleByte, ChunkSize::Unaligned,
+                        ChunkSize::DataSize),
+        /* blockSize */ testing::Values(256u, 1024u /*, 8192u*/),
+        /* flushMode */
+        testing::Values(FlushMode::Never, FlushMode::AfterEachChunk)),
+    TestParamToString);
+
+INSTANTIATE_TEST_SUITE_P(
+    DOM_IndexedDB_EncryptedStream_ParametrizedSeek, ParametrizedSeekCryptTest,
+    testing::Combine(
+        /* dataSize */ testing::Values(0u, 16u, 256u, 512u, 513u),
+        /* blockSize */ testing::Values(256u, 1024u /*, 8192u*/),
+        /* seekOperations */
+        testing::Values(/* NS_SEEK_SET only, single ops */
+                        std::vector<SeekOp>{{nsISeekableStream::NS_SEEK_SET,
+                                             SeekOffset::PlusDataSize}},
+                        std::vector<SeekOp>{{nsISeekableStream::NS_SEEK_SET,
+                                             SeekOffset::PlusHalfDataSize}},
+                        /* NS_SEEK_SET only, multiple ops */
+                        std::vector<SeekOp>{
+                            {nsISeekableStream::NS_SEEK_SET,
+                             SeekOffset::PlusHalfDataSize},
+                            {nsISeekableStream::NS_SEEK_SET, SeekOffset::Zero}},
+                        /* NS_SEEK_CUR only, single ops */
+                        std::vector<SeekOp>{
+                            {nsISeekableStream::NS_SEEK_CUR, SeekOffset::Zero}},
+                        std::vector<SeekOp>{{nsISeekableStream::NS_SEEK_CUR,
+                                             SeekOffset::PlusDataSize}},
+                        std::vector<SeekOp>{{nsISeekableStream::NS_SEEK_CUR,
+                                             SeekOffset::PlusHalfDataSize}},
+                        /* NS_SEEK_END only, single ops */
+                        std::vector<SeekOp>{
+                            {nsISeekableStream::NS_SEEK_END, SeekOffset::Zero}},
+                        std::vector<SeekOp>{{nsISeekableStream::NS_SEEK_END,
+                                             SeekOffset::MinusDataSize}},
+                        std::vector<SeekOp>{{nsISeekableStream::NS_SEEK_END,
+                                             SeekOffset::MinusHalfDataSize}})),
+    SeekTestParamToString);
diff --git a/dom/quota/test/gtest/TestFileOutputStream.cpp b/dom/quota/test/gtest/TestFileOutputStream.cpp
new file mode 100644
index 0000000000..231003fd6c
--- /dev/null
+++ b/dom/quota/test/gtest/TestFileOutputStream.cpp
@@ -0,0 +1,227 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/quota/Client.h"
+#include "mozilla/dom/quota/CommonMetadata.h"
+#include "mozilla/dom/quota/DirectoryLock.h"
+#include "mozilla/dom/quota/FileStreams.h"
+#include "mozilla/dom/quota/QuotaManager.h"
+#include "mozilla/gtest/MozAssertions.h"
+#include "nsIPrefBranch.h"
+#include "nsIPrefService.h"
+#include "QuotaManagerDependencyFixture.h"
+
+namespace mozilla::dom::quota::test {
+
+quota::OriginMetadata GetOutputStreamTestOriginMetadata() {
+  return quota::OriginMetadata{""_ns,
+                               "example.com"_ns,
+                               "http://example.com"_ns,
+                               "http://example.com"_ns,
+                               /* aIsPrivate */ false,
+                               quota::PERSISTENCE_TYPE_DEFAULT};
+}
+
+class TestFileOutputStream : public QuotaManagerDependencyFixture {
+ public:
+  static void SetUpTestCase() {
+    ASSERT_NO_FATAL_FAILURE(InitializeFixture());
+
+    nsCOMPtr<nsIPrefBranch> prefs = do_GetService(NS_PREFSERVICE_CONTRACTID);
+
+    prefs->SetIntPref("dom.quotaManager.temporaryStorage.fixedLimit",
+                      mQuotaLimit);
+  }
+
+  static void TearDownTestCase() {
+    nsCOMPtr<nsIPrefBranch> prefs = do_GetService(NS_PREFSERVICE_CONTRACTID);
+
+    prefs->ClearUserPref("dom.quotaManager.temporaryStorage.fixedLimit");
+
+    EXPECT_NO_FATAL_FAILURE(
+        ClearStoragesForOrigin(GetOutputStreamTestOriginMetadata()));
+
+    ASSERT_NO_FATAL_FAILURE(ShutdownFixture());
+  }
+
+  static const int32_t mQuotaLimit = 8192;
+};
+
+TEST_F(TestFileOutputStream, extendFileStreamWithSetEOF) {
+  auto backgroundTask = []() {
+    auto ioTask = []() {
+      quota::QuotaManager* quotaManager = quota::QuotaManager::Get();
+
+      auto originMetadata = GetOutputStreamTestOriginMetadata();
+
+      {
+        ASSERT_NS_SUCCEEDED(
+            quotaManager->EnsureTemporaryStorageIsInitializedInternal());
+
+        auto res = quotaManager->EnsureTemporaryOriginIsInitialized(
+            quota::PERSISTENCE_TYPE_DEFAULT, originMetadata);
+        ASSERT_TRUE(res.isOk());
+      }
+
+      const int64_t groupLimit =
+          static_cast<int64_t>(quotaManager->GetGroupLimit());
+      ASSERT_TRUE(mQuotaLimit * 1024LL == groupLimit);
+
+      // We don't use the tested stream itself to check the file size as it
+      // may report values which have not been written to disk.
+      RefPtr<quota::FileOutputStream> check =
+          MakeRefPtr<quota::FileOutputStream>(quota::PERSISTENCE_TYPE_DEFAULT,
+                                              originMetadata,
+                                              quota::Client::Type::SDB);
+
+      RefPtr<quota::FileOutputStream> stream =
+          MakeRefPtr<quota::FileOutputStream>(quota::PERSISTENCE_TYPE_DEFAULT,
+                                              originMetadata,
+                                              quota::Client::Type::SDB);
+
+      {
+        auto testPathRes = quotaManager->GetOriginDirectory(originMetadata);
+
+        ASSERT_TRUE(testPathRes.isOk());
+
+        nsCOMPtr<nsIFile> testPath = testPathRes.unwrap();
+
+        ASSERT_NS_SUCCEEDED(testPath->AppendRelativePath(u"sdb"_ns));
+
+        ASSERT_NS_SUCCEEDED(
+            testPath->AppendRelativePath(u"tTestFileOutputStream.txt"_ns));
+
+        bool exists = true;
+        ASSERT_NS_SUCCEEDED(testPath->Exists(&exists));
+
+        if (exists) {
+          ASSERT_NS_SUCCEEDED(testPath->Remove(/* recursive */ false));
+        }
+
+        ASSERT_NS_SUCCEEDED(testPath->Exists(&exists));
+        ASSERT_FALSE(exists);
+
+        ASSERT_NS_SUCCEEDED(testPath->Create(nsIFile::NORMAL_FILE_TYPE, 0666));
+
+        ASSERT_NS_SUCCEEDED(testPath->Exists(&exists));
+        ASSERT_TRUE(exists);
+
+        nsCOMPtr<nsIFile> checkPath;
+        ASSERT_NS_SUCCEEDED(testPath->Clone(getter_AddRefs(checkPath)));
+
+        const int32_t IOFlags = -1;
+        const int32_t perm = -1;
+        const int32_t behaviorFlags = 0;
+        ASSERT_NS_SUCCEEDED(
+            stream->Init(testPath, IOFlags, perm, behaviorFlags));
+
+        ASSERT_NS_SUCCEEDED(
+            check->Init(testPath, IOFlags, perm, behaviorFlags));
+      }
+
+      // Check that we start with an empty file
+      int64_t avail = 42;
+      ASSERT_NS_SUCCEEDED(check->GetSize(&avail));
+
+      ASSERT_TRUE(0 == avail);
+
+      // Enlarge the file
+      const int64_t toSize = groupLimit;
+      ASSERT_NS_SUCCEEDED(stream->Seek(nsISeekableStream::NS_SEEK_SET, toSize));
+
+      ASSERT_NS_SUCCEEDED(check->GetSize(&avail));
+
+      ASSERT_TRUE(0 == avail);
+
+      ASSERT_NS_SUCCEEDED(stream->SetEOF());
+
+      ASSERT_NS_SUCCEEDED(check->GetSize(&avail));
+
+      ASSERT_TRUE(toSize == avail);
+
+      // Try to enlarge the file past the limit
+      const int64_t overGroupLimit = groupLimit + 1;
+
+      // Seeking is allowed
+      ASSERT_NS_SUCCEEDED(
+          stream->Seek(nsISeekableStream::NS_SEEK_SET, overGroupLimit));
+
+      ASSERT_NS_SUCCEEDED(check->GetSize(&avail));
+
+      ASSERT_TRUE(toSize == avail);
+
+      // Setting file size to exceed quota should yield no device space error
+      ASSERT_TRUE(NS_ERROR_FILE_NO_DEVICE_SPACE == stream->SetEOF());
+
+      ASSERT_NS_SUCCEEDED(check->GetSize(&avail));
+
+      ASSERT_TRUE(toSize == avail);
+
+      // Shrink the file
+      const int64_t toHalfSize = toSize / 2;
+      ASSERT_NS_SUCCEEDED(
+          stream->Seek(nsISeekableStream::NS_SEEK_SET, toHalfSize));
+
+      ASSERT_NS_SUCCEEDED(check->GetSize(&avail));
+
+      ASSERT_TRUE(toSize == avail);
+
+      ASSERT_NS_SUCCEEDED(stream->SetEOF());
+
+      ASSERT_NS_SUCCEEDED(check->GetSize(&avail));
+
+      ASSERT_TRUE(toHalfSize == avail);
+
+      // Shrink the file back to nothing
+      ASSERT_NS_SUCCEEDED(stream->Seek(nsISeekableStream::NS_SEEK_SET, 0));
+
+      ASSERT_NS_SUCCEEDED(check->GetSize(&avail));
+
+      ASSERT_TRUE(toHalfSize == avail);
+
+      ASSERT_NS_SUCCEEDED(stream->SetEOF());
+
+      ASSERT_NS_SUCCEEDED(check->GetSize(&avail));
+
+      ASSERT_TRUE(0 == avail);
+    };
+
+    RefPtr<ClientDirectoryLock> directoryLock;
+
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    bool done = false;
+
+    quotaManager
+        ->OpenClientDirectory(
+            {GetOutputStreamTestOriginMetadata(), Client::SDB})
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&directoryLock, &done](RefPtr<ClientDirectoryLock> aResolveValue) {
+              directoryLock = std::move(aResolveValue);
+
+              done = true;
+            },
+            [&done](const nsresult aRejectValue) {
+              ASSERT_TRUE(false);
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+
+    ASSERT_TRUE(directoryLock);
+
+    PerformOnIOThread(std::move(ioTask));
+
+    directoryLock = nullptr;
+  };
+
+  PerformOnBackgroundThread(std::move(backgroundTask));
+}
+
+}  // namespace mozilla::dom::quota::test
diff --git a/dom/quota/test/gtest/TestFlatten.cpp b/dom/quota/test/gtest/TestFlatten.cpp
new file mode 100644
index 0000000000..5ca7675887
--- /dev/null
+++ b/dom/quota/test/gtest/TestFlatten.cpp
@@ -0,0 +1,81 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "Flatten.h"
+
+#include "gtest/gtest.h"
+
+#include "mozilla/Unused.h"
+#include "nsTArray.h"
+
+namespace mozilla::dom::quota {
+
+#ifdef __clang__
+#  pragma clang diagnostic push
+#  pragma clang diagnostic ignored "-Wunreachable-code-loop-increment"
+#endif
+TEST(Flatten, FlatEmpty)
+{
+  for (const auto& item : Flatten<int>(nsTArray<int>{})) {
+    Unused << item;
+    FAIL();
+  }
+}
+
+TEST(Flatten, NestedOuterEmpty)
+{
+  for (const auto& item : Flatten<int>(nsTArray<CopyableTArray<int>>{})) {
+    Unused << item;
+    FAIL();
+  }
+}
+
+TEST(Flatten, NestedInnerEmpty)
+{
+  for (const auto& item :
+       Flatten<int>(nsTArray<CopyableTArray<int>>{CopyableTArray<int>{}})) {
+    Unused << item;
+    FAIL();
+  }
+}
+#ifdef __clang__
+#  pragma clang diagnostic pop
+#endif
+
+TEST(Flatten, NestedInnerSingular)
+{
+  nsTArray<int> flattened;
+  for (const auto& item :
+       Flatten<int>(nsTArray<CopyableTArray<int>>{CopyableTArray<int>{1}})) {
+    flattened.AppendElement(item);
+  }
+
+  EXPECT_EQ(nsTArray{1}, flattened);
+}
+
+TEST(Flatten, NestedInnerSingulars)
+{
+  nsTArray<int> flattened;
+  for (const auto& item : Flatten<int>(nsTArray<CopyableTArray<int>>{
+           CopyableTArray<int>{1}, CopyableTArray<int>{2}})) {
+    flattened.AppendElement(item);
+  }
+
+  EXPECT_EQ((nsTArray<int>{{1, 2}}), flattened);
+}
+
+TEST(Flatten, NestedInnerNonSingulars)
+{
+  nsTArray<int> flattened;
+  for (const auto& item : Flatten<int>(nsTArray<CopyableTArray<int>>{
+           CopyableTArray<int>{1, 2}, CopyableTArray<int>{3, 4}})) {
+    flattened.AppendElement(item);
+  }
+
+  EXPECT_EQ((nsTArray<int>{{1, 2, 3, 4}}), flattened);
+}
+
+}  // namespace mozilla::dom::quota
diff --git a/dom/quota/test/gtest/TestForwardDecls.cpp b/dom/quota/test/gtest/TestForwardDecls.cpp
new file mode 100644
index 0000000000..223f83af03
--- /dev/null
+++ b/dom/quota/test/gtest/TestForwardDecls.cpp
@@ -0,0 +1,12 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include <type_traits>
+#include "mozilla/dom/quota/ForwardDecls.h"
+
+using namespace mozilla;
+
+static_assert(std::is_same_v<OkOrErr, Result<Ok, QMResult>>);
diff --git a/dom/quota/test/gtest/TestOriginParser.cpp b/dom/quota/test/gtest/TestOriginParser.cpp
new file mode 100644
index 0000000000..5cd4d2682b
--- /dev/null
+++ b/dom/quota/test/gtest/TestOriginParser.cpp
@@ -0,0 +1,25 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "OriginParser.h"
+
+#include "gtest/gtest.h"
+
+using namespace mozilla::dom::quota;
+
+TEST(OriginParser_IsUUIDOrigin, Valid)
+{ EXPECT_TRUE(IsUUIDOrigin("uuid://1ef9867c-e754-4303-a18b-684f0321f6e2"_ns)); }
+
+TEST(OriginParser_IsUUIDOrigin, Invalid)
+{
+  EXPECT_FALSE(IsUUIDOrigin("Invalid UUID Origin"_ns));
+
+  EXPECT_FALSE(IsUUIDOrigin("1ef9867c-e754-4303-a18b-684f0321f6e2"_ns));
+
+  EXPECT_FALSE(IsUUIDOrigin("uuid://1ef9867c-e754-4303-a18b"_ns));
+
+  EXPECT_FALSE(IsUUIDOrigin("uuid+++1ef9867c-e754-4303-a18b-684f0321f6e2"_ns));
+}
diff --git a/dom/quota/test/gtest/TestOriginScope.cpp b/dom/quota/test/gtest/TestOriginScope.cpp
new file mode 100644
index 0000000000..4afb45c1b4
--- /dev/null
+++ b/dom/quota/test/gtest/TestOriginScope.cpp
@@ -0,0 +1,107 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gtest/gtest.h"
+#include "mozilla/dom/quota/OriginScope.h"
+#include "nsStringFwd.h"
+#include "nsTDependentString.h"
+#include "nsTLiteralString.h"
+
+namespace mozilla::dom::quota {
+
+namespace {
+
+struct OriginTest {
+  const char* mOrigin;
+  bool mMatch;
+};
+
+void CheckOriginScopeMatchesOrigin(const OriginScope& aOriginScope,
+                                   const char* aOrigin, bool aMatch) {
+  bool result = aOriginScope.Matches(
+      OriginScope::FromOrigin(nsDependentCString(aOrigin)));
+
+  EXPECT_TRUE(result == aMatch);
+}
+
+}  // namespace
+
+TEST(DOM_Quota_OriginScope, SanityChecks)
+{
+  OriginScope originScope;
+
+  // Sanity checks.
+
+  {
+    constexpr auto origin = "http://www.mozilla.org"_ns;
+    originScope.SetFromOrigin(origin);
+    EXPECT_TRUE(originScope.IsOrigin());
+    EXPECT_TRUE(originScope.GetOrigin().Equals(origin));
+    EXPECT_TRUE(originScope.GetOriginNoSuffix().Equals(origin));
+  }
+
+  {
+    constexpr auto prefix = "http://www.mozilla.org"_ns;
+    originScope.SetFromPrefix(prefix);
+    EXPECT_TRUE(originScope.IsPrefix());
+    EXPECT_TRUE(originScope.GetOriginNoSuffix().Equals(prefix));
+  }
+
+  {
+    originScope.SetFromNull();
+    EXPECT_TRUE(originScope.IsNull());
+  }
+}
+
+TEST(DOM_Quota_OriginScope, MatchesOrigin)
+{
+  OriginScope originScope;
+
+  // Test each origin scope type against particular origins.
+
+  {
+    originScope.SetFromOrigin("http://www.mozilla.org"_ns);
+
+    static const OriginTest tests[] = {
+        {"http://www.mozilla.org", true},
+        {"http://www.example.org", false},
+    };
+
+    for (const auto& test : tests) {
+      CheckOriginScopeMatchesOrigin(originScope, test.mOrigin, test.mMatch);
+    }
+  }
+
+  {
+    originScope.SetFromPrefix("http://www.mozilla.org"_ns);
+
+    static const OriginTest tests[] = {
+        {"http://www.mozilla.org", true},
+        {"http://www.mozilla.org^userContextId=1", true},
+        {"http://www.example.org^userContextId=1", false},
+    };
+
+    for (const auto& test : tests) {
+      CheckOriginScopeMatchesOrigin(originScope, test.mOrigin, test.mMatch);
+    }
+  }
+
+  {
+    originScope.SetFromNull();
+
+    static const OriginTest tests[] = {
+        {"http://www.mozilla.org", true},
+        {"http://www.mozilla.org^userContextId=1", true},
+        {"http://www.example.org^userContextId=1", true},
+    };
+
+    for (const auto& test : tests) {
+      CheckOriginScopeMatchesOrigin(originScope, test.mOrigin, test.mMatch);
+    }
+  }
+}
+
+}  //  namespace mozilla::dom::quota
diff --git a/dom/quota/test/gtest/TestPersistenceType.cpp b/dom/quota/test/gtest/TestPersistenceType.cpp
new file mode 100644
index 0000000000..c4f1e5d581
--- /dev/null
+++ b/dom/quota/test/gtest/TestPersistenceType.cpp
@@ -0,0 +1,44 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/quota/PersistenceType.h"
+
+#include "gtest/gtest.h"
+
+#include "nsDirectoryServiceDefs.h"
+#include "nsDirectoryServiceUtils.h"
+#include "nsIFile.h"
+
+namespace mozilla::dom::quota {
+
+TEST(PersistenceType, FromFile)
+{
+  nsCOMPtr<nsIFile> base;
+  nsresult rv = NS_GetSpecialDirectory(NS_OS_TEMP_DIR, getter_AddRefs(base));
+  EXPECT_EQ(rv, NS_OK);
+
+  const auto testPersistenceType = [&base](const nsLiteralString& aString,
+                                           const Maybe<PersistenceType> aType) {
+    nsCOMPtr<nsIFile> file;
+
+    nsresult rv = base->Clone(getter_AddRefs(file));
+    EXPECT_EQ(rv, NS_OK);
+
+    rv = file->Append(aString);
+    EXPECT_EQ(rv, NS_OK);
+
+    auto maybePersistenceType = PersistenceTypeFromFile(*file, fallible);
+    EXPECT_EQ(maybePersistenceType, aType);
+  };
+
+  testPersistenceType(u"permanent"_ns, Some(PERSISTENCE_TYPE_PERSISTENT));
+  testPersistenceType(u"temporary"_ns, Some(PERSISTENCE_TYPE_TEMPORARY));
+  testPersistenceType(u"default"_ns, Some(PERSISTENCE_TYPE_DEFAULT));
+  testPersistenceType(u"persistent"_ns, Nothing());
+  testPersistenceType(u"foobar"_ns, Nothing());
+}
+
+}  // namespace mozilla::dom::quota
diff --git a/dom/quota/test/gtest/TestQMResult.cpp b/dom/quota/test/gtest/TestQMResult.cpp
new file mode 100644
index 0000000000..94cbec7364
--- /dev/null
+++ b/dom/quota/test/gtest/TestQMResult.cpp
@@ -0,0 +1,72 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "Common.h"
+#include "gtest/gtest.h"
+#include "mozilla/dom/QMResult.h"
+
+using namespace mozilla;
+using namespace mozilla::dom::quota;
+
+class DOM_Quota_QMResult : public DOM_Quota_Test {};
+
+#ifdef QM_ERROR_STACKS_ENABLED
+TEST_F(DOM_Quota_QMResult, Construct_Default) {
+  QMResult res;
+
+  IncreaseExpectedStackId();
+
+  ASSERT_EQ(res.StackId(), ExpectedStackId());
+  ASSERT_EQ(res.FrameId(), 1u);
+  ASSERT_EQ(res.NSResult(), NS_OK);
+}
+#endif
+
+TEST_F(DOM_Quota_QMResult, Construct_FromNSResult) {
+  QMResult res(NS_ERROR_FAILURE);
+
+#ifdef QM_ERROR_STACKS_ENABLED
+  IncreaseExpectedStackId();
+
+  ASSERT_EQ(res.StackId(), ExpectedStackId());
+  ASSERT_EQ(res.FrameId(), 1u);
+  ASSERT_EQ(res.NSResult(), NS_ERROR_FAILURE);
+#else
+  ASSERT_EQ(res, NS_ERROR_FAILURE);
+#endif
+}
+
+#ifdef QM_ERROR_STACKS_ENABLED
+TEST_F(DOM_Quota_QMResult, Propagate) {
+  QMResult res1(NS_ERROR_FAILURE);
+
+  IncreaseExpectedStackId();
+
+  ASSERT_EQ(res1.StackId(), ExpectedStackId());
+  ASSERT_EQ(res1.FrameId(), 1u);
+  ASSERT_EQ(res1.NSResult(), NS_ERROR_FAILURE);
+
+  QMResult res2 = res1.Propagate();
+
+  ASSERT_EQ(res2.StackId(), ExpectedStackId());
+  ASSERT_EQ(res2.FrameId(), 2u);
+  ASSERT_EQ(res2.NSResult(), NS_ERROR_FAILURE);
+}
+#endif
+
+TEST_F(DOM_Quota_QMResult, ToQMResult) {
+  auto res = ToQMResult(NS_ERROR_FAILURE);
+
+#ifdef QM_ERROR_STACKS_ENABLED
+  IncreaseExpectedStackId();
+
+  ASSERT_EQ(res.StackId(), ExpectedStackId());
+  ASSERT_EQ(res.FrameId(), 1u);
+  ASSERT_EQ(res.NSResult(), NS_ERROR_FAILURE);
+#else
+  ASSERT_EQ(res, NS_ERROR_FAILURE);
+#endif
+}
diff --git a/dom/quota/test/gtest/TestQuotaCommon.cpp b/dom/quota/test/gtest/TestQuotaCommon.cpp
new file mode 100644
index 0000000000..2367f08cd6
--- /dev/null
+++ b/dom/quota/test/gtest/TestQuotaCommon.cpp
@@ -0,0 +1,2288 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/quota/QuotaCommon.h"
+
+#include "gtest/gtest.h"
+
+#include <algorithm>
+#include <array>
+#include <cstddef>
+#include <cstdint>
+#include <map>
+#include <new>
+#include <ostream>
+#include <type_traits>
+#include <utility>
+#include <vector>
+#include "ErrorList.h"
+#include "mozilla/Assertions.h"
+#include "mozilla/Result.h"
+#include "mozilla/ResultExtensions.h"
+#include "mozilla/ResultVariant.h"
+#include "mozilla/Unused.h"
+#include "mozilla/fallible.h"
+#include "mozilla/dom/quota/QuotaTestParent.h"
+#include "mozilla/dom/quota/ResultExtensions.h"
+#include "nsCOMPtr.h"
+#include "nsDirectoryServiceDefs.h"
+#include "nsDirectoryServiceUtils.h"
+#include "nsIFile.h"
+#include "nsLiteralString.h"
+#include "nsString.h"
+#include "nsStringFwd.h"
+#include "nsTLiteralString.h"
+
+class nsISupports;
+
+namespace mozilla::dom::quota {
+
+namespace {
+
+void CheckUnknownFileEntry(nsIFile& aBase, const nsAString& aName,
+                           const bool aWarnIfFile, const bool aWarnIfDir) {
+  nsCOMPtr<nsIFile> file;
+  nsresult rv = aBase.Clone(getter_AddRefs(file));
+  ASSERT_EQ(rv, NS_OK);
+
+  rv = file->Append(aName);
+  ASSERT_EQ(rv, NS_OK);
+
+  rv = file->Create(nsIFile::NORMAL_FILE_TYPE, 0600);
+  ASSERT_EQ(rv, NS_OK);
+
+  auto okOrErr = WARN_IF_FILE_IS_UNKNOWN(*file);
+  ASSERT_TRUE(okOrErr.isOk());
+
+#ifdef DEBUG
+  EXPECT_TRUE(okOrErr.inspect() == aWarnIfFile);
+#else
+  EXPECT_TRUE(okOrErr.inspect() == false);
+#endif
+
+  rv = file->Remove(false);
+  ASSERT_EQ(rv, NS_OK);
+
+  rv = file->Create(nsIFile::DIRECTORY_TYPE, 0700);
+  ASSERT_EQ(rv, NS_OK);
+
+  okOrErr = WARN_IF_FILE_IS_UNKNOWN(*file);
+  ASSERT_TRUE(okOrErr.isOk());
+
+#ifdef DEBUG
+  EXPECT_TRUE(okOrErr.inspect() == aWarnIfDir);
+#else
+  EXPECT_TRUE(okOrErr.inspect() == false);
+#endif
+
+  rv = file->Remove(false);
+  ASSERT_EQ(rv, NS_OK);
+}
+
+}  // namespace
+
+TEST(QuotaCommon_WarnIfFileIsUnknown, Basics)
+{
+  nsCOMPtr<nsIFile> base;
+  nsresult rv = NS_GetSpecialDirectory(NS_OS_TEMP_DIR, getter_AddRefs(base));
+  ASSERT_EQ(rv, NS_OK);
+
+  rv = base->Append(u"mozquotatests"_ns);
+  ASSERT_EQ(rv, NS_OK);
+
+  base->Remove(true);
+
+  rv = base->Create(nsIFile::DIRECTORY_TYPE, 0700);
+  ASSERT_EQ(rv, NS_OK);
+
+  CheckUnknownFileEntry(*base, u"foo.bar"_ns, true, true);
+  CheckUnknownFileEntry(*base, u".DS_Store"_ns, false, true);
+  CheckUnknownFileEntry(*base, u".desktop"_ns, false, true);
+  CheckUnknownFileEntry(*base, u"desktop.ini"_ns, false, true);
+  CheckUnknownFileEntry(*base, u"DESKTOP.INI"_ns, false, true);
+  CheckUnknownFileEntry(*base, u"thumbs.db"_ns, false, true);
+  CheckUnknownFileEntry(*base, u"THUMBS.DB"_ns, false, true);
+  CheckUnknownFileEntry(*base, u".xyz"_ns, false, true);
+
+  rv = base->Remove(true);
+  ASSERT_EQ(rv, NS_OK);
+}
+
+mozilla::ipc::IPCResult QuotaTestParent::RecvTry_Success_CustomErr_QmIpcFail(
+    bool* aTryDidNotReturn) {
+  QM_TRY(MOZ_TO_RESULT(NS_OK), QM_IPC_FAIL(this));
+
+  *aTryDidNotReturn = true;
+
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult QuotaTestParent::RecvTry_Success_CustomErr_IpcFail(
+    bool* aTryDidNotReturn) {
+  QM_TRY(MOZ_TO_RESULT(NS_OK), IPC_FAIL(this, "Custom why"));
+
+  *aTryDidNotReturn = true;
+
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult
+QuotaTestParent::RecvTryInspect_Success_CustomErr_QmIpcFail(
+    bool* aTryDidNotReturn) {
+  QM_TRY_INSPECT(const auto& x, (mozilla::Result<int32_t, nsresult>{42}),
+                 QM_IPC_FAIL(this));
+  Unused << x;
+
+  *aTryDidNotReturn = true;
+
+  return IPC_OK();
+}
+
+mozilla::ipc::IPCResult
+QuotaTestParent::RecvTryInspect_Success_CustomErr_IpcFail(
+    bool* aTryDidNotReturn) {
+  QM_TRY_INSPECT(const auto& x, (mozilla::Result<int32_t, nsresult>{42}),
+                 IPC_FAIL(this, "Custom why"));
+  Unused << x;
+
+  *aTryDidNotReturn = true;
+
+  return IPC_OK();
+}
+
+#ifdef __clang__
+#  pragma clang diagnostic push
+#  pragma clang diagnostic ignored "-Wunreachable-code"
+#endif
+
+TEST(QuotaCommon_Try, Success)
+{
+  bool tryDidNotReturn = false;
+
+  nsresult rv = [&tryDidNotReturn]() -> nsresult {
+    QM_TRY(MOZ_TO_RESULT(NS_OK));
+
+    tryDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_TRUE(tryDidNotReturn);
+  EXPECT_EQ(rv, NS_OK);
+}
+
+TEST(QuotaCommon_Try, Success_CustomErr_QmIpcFail)
+{
+  auto foo = MakeRefPtr<QuotaTestParent>();
+
+  bool tryDidNotReturn = false;
+
+  auto res = foo->RecvTry_Success_CustomErr_QmIpcFail(&tryDidNotReturn);
+
+  EXPECT_TRUE(tryDidNotReturn);
+  EXPECT_TRUE(res);
+}
+
+TEST(QuotaCommon_Try, Success_CustomErr_IpcFail)
+{
+  auto foo = MakeRefPtr<QuotaTestParent>();
+
+  bool tryDidNotReturn = false;
+
+  auto res = foo->RecvTry_Success_CustomErr_IpcFail(&tryDidNotReturn);
+
+  EXPECT_TRUE(tryDidNotReturn);
+  EXPECT_TRUE(res);
+}
+
+#ifdef DEBUG
+TEST(QuotaCommon_Try, Success_CustomErr_AssertUnreachable)
+{
+  bool tryDidNotReturn = false;
+
+  nsresult rv = [&tryDidNotReturn]() -> nsresult {
+    QM_TRY(MOZ_TO_RESULT(NS_OK), QM_ASSERT_UNREACHABLE);
+
+    tryDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_TRUE(tryDidNotReturn);
+  EXPECT_EQ(rv, NS_OK);
+}
+
+TEST(QuotaCommon_Try, Success_NoErr_AssertUnreachable)
+{
+  bool tryDidNotReturn = false;
+
+  [&tryDidNotReturn]() -> void {
+    QM_TRY(MOZ_TO_RESULT(NS_OK), QM_ASSERT_UNREACHABLE_VOID);
+
+    tryDidNotReturn = true;
+  }();
+
+  EXPECT_TRUE(tryDidNotReturn);
+}
+#else
+#  if defined(QM_ASSERT_UNREACHABLE) || defined(QM_ASSERT_UNREACHABLE_VOID)
+#error QM_ASSERT_UNREACHABLE and QM_ASSERT_UNREACHABLE_VOID should not be defined.
+#  endif
+#endif
+
+#ifdef MOZ_DIAGNOSTIC_ASSERT_ENABLED
+TEST(QuotaCommon_Try, Success_CustomErr_DiagnosticAssertUnreachable)
+{
+  bool tryDidNotReturn = false;
+
+  nsresult rv = [&tryDidNotReturn]() -> nsresult {
+    QM_TRY(MOZ_TO_RESULT(NS_OK), QM_DIAGNOSTIC_ASSERT_UNREACHABLE);
+
+    tryDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_TRUE(tryDidNotReturn);
+  EXPECT_EQ(rv, NS_OK);
+}
+
+TEST(QuotaCommon_Try, Success_NoErr_DiagnosticAssertUnreachable)
+{
+  bool tryDidNotReturn = false;
+
+  [&tryDidNotReturn]() -> void {
+    QM_TRY(MOZ_TO_RESULT(NS_OK), QM_DIAGNOSTIC_ASSERT_UNREACHABLE_VOID);
+
+    tryDidNotReturn = true;
+  }();
+
+  EXPECT_TRUE(tryDidNotReturn);
+}
+#else
+#  if defined(QM_DIAGNOSTIC_ASSERT_UNREACHABLE) || \
+      defined(QM_DIAGNOSTIC_ASSERT_UNREACHABLE_VOID)
+#error QM_DIAGNOSTIC_ASSERT_UNREACHABLE and QM_DIAGNOSTIC_ASSERT_UNREACHABLE_VOID should not be defined.
+#  endif
+#endif
+
+TEST(QuotaCommon_Try, Success_CustomErr_CustomLambda)
+{
+#define SUBTEST(...)                                                 \
+  {                                                                  \
+    bool tryDidNotReturn = false;                                    \
+                                                                     \
+    nsresult rv = [&tryDidNotReturn]() -> nsresult {                 \
+      QM_TRY(MOZ_TO_RESULT(NS_OK), [](__VA_ARGS__) { return aRv; }); \
+                                                                     \
+      tryDidNotReturn = true;                                        \
+                                                                     \
+      return NS_OK;                                                  \
+    }();                                                             \
+                                                                     \
+    EXPECT_TRUE(tryDidNotReturn);                                    \
+    EXPECT_EQ(rv, NS_OK);                                            \
+  }
+
+  SUBTEST(const char*, nsresult aRv);
+  SUBTEST(nsresult aRv);
+
+#undef SUBTEST
+}
+
+TEST(QuotaCommon_Try, Success_WithCleanup)
+{
+  bool tryCleanupRan = false;
+  bool tryDidNotReturn = false;
+
+  nsresult rv = [&tryCleanupRan, &tryDidNotReturn]() -> nsresult {
+    QM_TRY(MOZ_TO_RESULT(NS_OK), QM_PROPAGATE,
+           [&tryCleanupRan](const auto&) { tryCleanupRan = true; });
+
+    tryDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_FALSE(tryCleanupRan);
+  EXPECT_TRUE(tryDidNotReturn);
+  EXPECT_EQ(rv, NS_OK);
+}
+
+TEST(QuotaCommon_Try, Failure_PropagateErr)
+{
+  bool tryDidNotReturn = false;
+
+  nsresult rv = [&tryDidNotReturn]() -> nsresult {
+    QM_TRY(MOZ_TO_RESULT(NS_ERROR_FAILURE));
+
+    tryDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_FALSE(tryDidNotReturn);
+  EXPECT_EQ(rv, NS_ERROR_FAILURE);
+}
+
+TEST(QuotaCommon_Try, Failure_CustomErr)
+{
+  bool tryDidNotReturn = false;
+
+  nsresult rv = [&tryDidNotReturn]() -> nsresult {
+    QM_TRY(MOZ_TO_RESULT(NS_ERROR_FAILURE), NS_ERROR_UNEXPECTED);
+
+    tryDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_FALSE(tryDidNotReturn);
+  EXPECT_EQ(rv, NS_ERROR_UNEXPECTED);
+}
+
+TEST(QuotaCommon_Try, Failure_CustomErr_CustomLambda)
+{
+#define SUBTEST(...)                                           \
+  {                                                            \
+    bool tryDidNotReturn = false;                              \
+                                                               \
+    nsresult rv = [&tryDidNotReturn]() -> nsresult {           \
+      QM_TRY(MOZ_TO_RESULT(NS_ERROR_FAILURE),                  \
+             [](__VA_ARGS__) { return NS_ERROR_UNEXPECTED; }); \
+                                                               \
+      tryDidNotReturn = true;                                  \
+                                                               \
+      return NS_OK;                                            \
+    }();                                                       \
+                                                               \
+    EXPECT_FALSE(tryDidNotReturn);                             \
+    EXPECT_EQ(rv, NS_ERROR_UNEXPECTED);                        \
+  }
+
+  SUBTEST(const char* aFunc, nsresult);
+  SUBTEST(nsresult rv);
+
+#undef SUBTEST
+}
+
+TEST(QuotaCommon_Try, Failure_NoErr)
+{
+  bool tryDidNotReturn = false;
+
+  [&tryDidNotReturn]() -> void {
+    QM_TRY(MOZ_TO_RESULT(NS_ERROR_FAILURE), QM_VOID);
+
+    tryDidNotReturn = true;
+  }();
+
+  EXPECT_FALSE(tryDidNotReturn);
+}
+
+TEST(QuotaCommon_Try, Failure_WithCleanup)
+{
+  bool tryCleanupRan = false;
+  bool tryDidNotReturn = false;
+
+  nsresult rv = [&tryCleanupRan, &tryDidNotReturn]() -> nsresult {
+    QM_TRY(MOZ_TO_RESULT(NS_ERROR_FAILURE), QM_PROPAGATE,
+           [&tryCleanupRan](const auto& result) {
+             EXPECT_EQ(result, NS_ERROR_FAILURE);
+
+             tryCleanupRan = true;
+           });
+
+    tryDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_TRUE(tryCleanupRan);
+  EXPECT_FALSE(tryDidNotReturn);
+  EXPECT_EQ(rv, NS_ERROR_FAILURE);
+}
+
+TEST(QuotaCommon_Try, Failure_WithCleanup_UnwrapErr)
+{
+  bool tryCleanupRan = false;
+  bool tryDidNotReturn = false;
+
+  nsresult rv;
+
+  [&tryCleanupRan, &tryDidNotReturn](nsresult& aRv) -> void {
+    QM_TRY(MOZ_TO_RESULT(NS_ERROR_FAILURE), QM_VOID,
+           ([&tryCleanupRan, &aRv](auto& result) {
+             EXPECT_EQ(result, NS_ERROR_FAILURE);
+
+             aRv = result;
+
+             tryCleanupRan = true;
+           }));
+
+    tryDidNotReturn = true;
+
+    aRv = NS_OK;
+  }(rv);
+
+  EXPECT_TRUE(tryCleanupRan);
+  EXPECT_FALSE(tryDidNotReturn);
+  EXPECT_EQ(rv, NS_ERROR_FAILURE);
+}
+
+TEST(QuotaCommon_Try, Failure_WithCleanupAndPredicate)
+{
+  auto predicate = []() {
+    static bool calledOnce = false;
+    const bool result = !calledOnce;
+    calledOnce = true;
+    return result;
+  };
+
+  {
+    bool tryDidNotReturn = false;
+
+    nsresult rv = [&predicate, &tryDidNotReturn]() -> nsresult {
+      QM_TRY(MOZ_TO_RESULT(NS_ERROR_FAILURE), QM_PROPAGATE, QM_NO_CLEANUP,
+             predicate);
+
+      tryDidNotReturn = true;
+
+      return NS_OK;
+    }();
+
+    EXPECT_FALSE(tryDidNotReturn);
+    EXPECT_EQ(rv, NS_ERROR_FAILURE);
+  }
+
+  {
+    bool tryDidNotReturn = false;
+
+    nsresult rv = [&predicate, &tryDidNotReturn]() -> nsresult {
+      QM_TRY(MOZ_TO_RESULT(NS_ERROR_FAILURE), QM_PROPAGATE, QM_NO_CLEANUP,
+             predicate);
+
+      tryDidNotReturn = true;
+
+      return NS_OK;
+    }();
+
+    EXPECT_FALSE(tryDidNotReturn);
+    EXPECT_EQ(rv, NS_ERROR_FAILURE);
+  }
+}
+
+TEST(QuotaCommon_Try, SameLine)
+{
+  // clang-format off
+  QM_TRY(MOZ_TO_RESULT(NS_OK), QM_VOID); QM_TRY(MOZ_TO_RESULT(NS_OK), QM_VOID);
+  // clang-format on
+}
+
+TEST(QuotaCommon_Try, NestingMadness_Success)
+{
+  bool nestedTryDidNotReturn = false;
+  bool tryDidNotReturn = false;
+
+  nsresult rv = [&nestedTryDidNotReturn, &tryDidNotReturn]() -> nsresult {
+    QM_TRY(([&nestedTryDidNotReturn]() -> Result<Ok, nsresult> {
+      QM_TRY(MOZ_TO_RESULT(NS_OK));
+
+      nestedTryDidNotReturn = true;
+
+      return Ok();
+    }()));
+
+    tryDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_TRUE(nestedTryDidNotReturn);
+  EXPECT_TRUE(tryDidNotReturn);
+  EXPECT_EQ(rv, NS_OK);
+}
+
+TEST(QuotaCommon_Try, NestingMadness_Failure)
+{
+  bool nestedTryDidNotReturn = false;
+  bool tryDidNotReturn = false;
+
+  nsresult rv = [&nestedTryDidNotReturn, &tryDidNotReturn]() -> nsresult {
+    QM_TRY(([&nestedTryDidNotReturn]() -> Result<Ok, nsresult> {
+      QM_TRY(MOZ_TO_RESULT(NS_ERROR_FAILURE));
+
+      nestedTryDidNotReturn = true;
+
+      return Ok();
+    }()));
+
+    tryDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_FALSE(nestedTryDidNotReturn);
+  EXPECT_FALSE(tryDidNotReturn);
+  EXPECT_EQ(rv, NS_ERROR_FAILURE);
+}
+
+TEST(QuotaCommon_Try, NestingMadness_Multiple_Success)
+{
+  bool nestedTry1DidNotReturn = false;
+  bool nestedTry2DidNotReturn = false;
+  bool tryDidNotReturn = false;
+
+  nsresult rv = [&nestedTry1DidNotReturn, &nestedTry2DidNotReturn,
+                 &tryDidNotReturn]() -> nsresult {
+    QM_TRY(([&nestedTry1DidNotReturn,
+             &nestedTry2DidNotReturn]() -> Result<Ok, nsresult> {
+      QM_TRY(MOZ_TO_RESULT(NS_OK));
+
+      nestedTry1DidNotReturn = true;
+
+      QM_TRY(MOZ_TO_RESULT(NS_OK));
+
+      nestedTry2DidNotReturn = true;
+
+      return Ok();
+    }()));
+
+    tryDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_TRUE(nestedTry1DidNotReturn);
+  EXPECT_TRUE(nestedTry2DidNotReturn);
+  EXPECT_TRUE(tryDidNotReturn);
+  EXPECT_EQ(rv, NS_OK);
+}
+
+TEST(QuotaCommon_Try, NestingMadness_Multiple_Failure1)
+{
+  bool nestedTry1DidNotReturn = false;
+  bool nestedTry2DidNotReturn = false;
+  bool tryDidNotReturn = false;
+
+  nsresult rv = [&nestedTry1DidNotReturn, &nestedTry2DidNotReturn,
+                 &tryDidNotReturn]() -> nsresult {
+    QM_TRY(([&nestedTry1DidNotReturn,
+             &nestedTry2DidNotReturn]() -> Result<Ok, nsresult> {
+      QM_TRY(MOZ_TO_RESULT(NS_ERROR_FAILURE));
+
+      nestedTry1DidNotReturn = true;
+
+      QM_TRY(MOZ_TO_RESULT(NS_OK));
+
+      nestedTry2DidNotReturn = true;
+
+      return Ok();
+    }()));
+
+    tryDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_FALSE(nestedTry1DidNotReturn);
+  EXPECT_FALSE(nestedTry2DidNotReturn);
+  EXPECT_FALSE(tryDidNotReturn);
+  EXPECT_EQ(rv, NS_ERROR_FAILURE);
+}
+
+TEST(QuotaCommon_Try, NestingMadness_Multiple_Failure2)
+{
+  bool nestedTry1DidNotReturn = false;
+  bool nestedTry2DidNotReturn = false;
+  bool tryDidNotReturn = false;
+
+  nsresult rv = [&nestedTry1DidNotReturn, &nestedTry2DidNotReturn,
+                 &tryDidNotReturn]() -> nsresult {
+    QM_TRY(([&nestedTry1DidNotReturn,
+             &nestedTry2DidNotReturn]() -> Result<Ok, nsresult> {
+      QM_TRY(MOZ_TO_RESULT(NS_OK));
+
+      nestedTry1DidNotReturn = true;
+
+      QM_TRY(MOZ_TO_RESULT(NS_ERROR_FAILURE));
+
+      nestedTry2DidNotReturn = true;
+
+      return Ok();
+    }()));
+
+    tryDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_TRUE(nestedTry1DidNotReturn);
+  EXPECT_FALSE(nestedTry2DidNotReturn);
+  EXPECT_FALSE(tryDidNotReturn);
+  EXPECT_EQ(rv, NS_ERROR_FAILURE);
+}
+
+TEST(QuotaCommon_TryInspect, Success)
+{
+  bool tryInspectDidNotReturn = false;
+
+  nsresult rv = [&tryInspectDidNotReturn]() -> nsresult {
+    QM_TRY_INSPECT(const auto& x, (Result<int32_t, nsresult>{42}));
+    EXPECT_EQ(x, 42);
+
+    tryInspectDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_TRUE(tryInspectDidNotReturn);
+  EXPECT_EQ(rv, NS_OK);
+}
+
+TEST(QuotaCommon_TryInspect, Success_CustomErr_QmIpcFail)
+{
+  auto foo = MakeRefPtr<QuotaTestParent>();
+
+  bool tryDidNotReturn = false;
+
+  auto res = foo->RecvTryInspect_Success_CustomErr_QmIpcFail(&tryDidNotReturn);
+
+  EXPECT_TRUE(tryDidNotReturn);
+  EXPECT_TRUE(res);
+}
+
+TEST(QuotaCommon_TryInspect, Success_CustomErr_IpcFail)
+{
+  auto foo = MakeRefPtr<QuotaTestParent>();
+
+  bool tryDidNotReturn = false;
+
+  auto res = foo->RecvTryInspect_Success_CustomErr_IpcFail(&tryDidNotReturn);
+
+  EXPECT_TRUE(tryDidNotReturn);
+  EXPECT_TRUE(res);
+}
+
+#ifdef DEBUG
+TEST(QuotaCommon_TryInspect, Success_CustomErr_AssertUnreachable)
+{
+  bool tryInspectDidNotReturn = false;
+
+  nsresult rv = [&tryInspectDidNotReturn]() -> nsresult {
+    QM_TRY_INSPECT(const auto& x, (Result<int32_t, nsresult>{42}),
+                   QM_ASSERT_UNREACHABLE);
+    EXPECT_EQ(x, 42);
+
+    tryInspectDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_TRUE(tryInspectDidNotReturn);
+  EXPECT_EQ(rv, NS_OK);
+}
+
+TEST(QuotaCommon_TryInspect, Success_NoErr_AssertUnreachable)
+{
+  bool tryInspectDidNotReturn = false;
+
+  [&tryInspectDidNotReturn]() -> void {
+    QM_TRY_INSPECT(const auto& x, (Result<int32_t, nsresult>{42}),
+                   QM_ASSERT_UNREACHABLE_VOID);
+    EXPECT_EQ(x, 42);
+
+    tryInspectDidNotReturn = true;
+  }();
+
+  EXPECT_TRUE(tryInspectDidNotReturn);
+}
+#endif
+
+TEST(QuotaCommon_TryInspect, Success_CustomErr_CustomLambda)
+{
+#define SUBTEST(...)                                                 \
+  {                                                                  \
+    bool tryInspectDidNotReturn = false;                             \
+                                                                     \
+    nsresult rv = [&tryInspectDidNotReturn]() -> nsresult {          \
+      QM_TRY_INSPECT(const auto& x, (Result<int32_t, nsresult>{42}), \
+                     [](__VA_ARGS__) { return aRv; });               \
+      EXPECT_EQ(x, 42);                                              \
+                                                                     \
+      tryInspectDidNotReturn = true;                                 \
+                                                                     \
+      return NS_OK;                                                  \
+    }();                                                             \
+                                                                     \
+    EXPECT_TRUE(tryInspectDidNotReturn);                             \
+    EXPECT_EQ(rv, NS_OK);                                            \
+  }
+
+  SUBTEST(const char*, nsresult aRv);
+  SUBTEST(nsresult aRv);
+
+#undef SUBTEST
+}
+
+TEST(QuotaCommon_TryInspect, Success_WithCleanup)
+{
+  bool tryInspectCleanupRan = false;
+  bool tryInspectDidNotReturn = false;
+
+  nsresult rv = [&tryInspectCleanupRan, &tryInspectDidNotReturn]() -> nsresult {
+    QM_TRY_INSPECT(
+        const auto& x, (Result<int32_t, nsresult>{42}), QM_PROPAGATE,
+        [&tryInspectCleanupRan](const auto&) { tryInspectCleanupRan = true; });
+    EXPECT_EQ(x, 42);
+
+    tryInspectDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_FALSE(tryInspectCleanupRan);
+  EXPECT_TRUE(tryInspectDidNotReturn);
+  EXPECT_EQ(rv, NS_OK);
+}
+
+TEST(QuotaCommon_TryInspect, Failure_PropagateErr)
+{
+  bool tryInspectDidNotReturn = false;
+
+  nsresult rv = [&tryInspectDidNotReturn]() -> nsresult {
+    QM_TRY_INSPECT(const auto& x,
+                   (Result<int32_t, nsresult>{Err(NS_ERROR_FAILURE)}));
+    Unused << x;
+
+    tryInspectDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_FALSE(tryInspectDidNotReturn);
+  EXPECT_EQ(rv, NS_ERROR_FAILURE);
+}
+
+TEST(QuotaCommon_TryInspect, Failure_CustomErr)
+{
+  bool tryInspectDidNotReturn = false;
+
+  nsresult rv = [&tryInspectDidNotReturn]() -> nsresult {
+    QM_TRY_INSPECT(const auto& x,
+                   (Result<int32_t, nsresult>{Err(NS_ERROR_FAILURE)}),
+                   NS_ERROR_UNEXPECTED);
+    Unused << x;
+
+    tryInspectDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_FALSE(tryInspectDidNotReturn);
+  EXPECT_EQ(rv, NS_ERROR_UNEXPECTED);
+}
+
+TEST(QuotaCommon_TryInspect, Failure_CustomErr_CustomLambda)
+{
+#define SUBTEST(...)                                                     \
+  {                                                                      \
+    bool tryInspectDidNotReturn = false;                                 \
+                                                                         \
+    nsresult rv = [&tryInspectDidNotReturn]() -> nsresult {              \
+      QM_TRY_INSPECT(const auto& x,                                      \
+                     (Result<int32_t, nsresult>{Err(NS_ERROR_FAILURE)}), \
+                     [](__VA_ARGS__) { return NS_ERROR_UNEXPECTED; });   \
+      Unused << x;                                                       \
+                                                                         \
+      tryInspectDidNotReturn = true;                                     \
+                                                                         \
+      return NS_OK;                                                      \
+    }();                                                                 \
+                                                                         \
+    EXPECT_FALSE(tryInspectDidNotReturn);                                \
+    EXPECT_EQ(rv, NS_ERROR_UNEXPECTED);                                  \
+  }
+
+  SUBTEST(const char*, nsresult);
+  SUBTEST(nsresult);
+
+#undef SUBTEST
+}
+
+TEST(QuotaCommon_TryInspect, Failure_NoErr)
+{
+  bool tryInspectDidNotReturn = false;
+
+  [&tryInspectDidNotReturn]() -> void {
+    QM_TRY_INSPECT(const auto& x,
+                   (Result<int32_t, nsresult>{Err(NS_ERROR_FAILURE)}), QM_VOID);
+    Unused << x;
+
+    tryInspectDidNotReturn = true;
+  }();
+
+  EXPECT_FALSE(tryInspectDidNotReturn);
+}
+
+TEST(QuotaCommon_TryInspect, Failure_WithCleanup)
+{
+  bool tryInspectCleanupRan = false;
+  bool tryInspectDidNotReturn = false;
+
+  nsresult rv = [&tryInspectCleanupRan, &tryInspectDidNotReturn]() -> nsresult {
+    QM_TRY_INSPECT(const auto& x,
+                   (Result<int32_t, nsresult>{Err(NS_ERROR_FAILURE)}),
+                   QM_PROPAGATE, [&tryInspectCleanupRan](const auto& result) {
+                     EXPECT_EQ(result, NS_ERROR_FAILURE);
+
+                     tryInspectCleanupRan = true;
+                   });
+    Unused << x;
+
+    tryInspectDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_TRUE(tryInspectCleanupRan);
+  EXPECT_FALSE(tryInspectDidNotReturn);
+  EXPECT_EQ(rv, NS_ERROR_FAILURE);
+}
+
+TEST(QuotaCommon_TryInspect, Failure_WithCleanup_UnwrapErr)
+{
+  bool tryInspectCleanupRan = false;
+  bool tryInspectDidNotReturn = false;
+
+  nsresult rv;
+
+  [&tryInspectCleanupRan, &tryInspectDidNotReturn](nsresult& aRv) -> void {
+    QM_TRY_INSPECT(const auto& x,
+                   (Result<int32_t, nsresult>{Err(NS_ERROR_FAILURE)}), QM_VOID,
+                   ([&tryInspectCleanupRan, &aRv](auto& result) {
+                     EXPECT_EQ(result, NS_ERROR_FAILURE);
+
+                     aRv = result;
+
+                     tryInspectCleanupRan = true;
+                   }));
+    Unused << x;
+
+    tryInspectDidNotReturn = true;
+
+    aRv = NS_OK;
+  }(rv);
+
+  EXPECT_TRUE(tryInspectCleanupRan);
+  EXPECT_FALSE(tryInspectDidNotReturn);
+  EXPECT_EQ(rv, NS_ERROR_FAILURE);
+}
+
+TEST(QuotaCommon_TryInspect, ConstDecl)
+{
+  QM_TRY_INSPECT(const int32_t& x, (Result<int32_t, nsresult>{42}), QM_VOID);
+
+  static_assert(std::is_same_v<decltype(x), const int32_t&>);
+
+  EXPECT_EQ(x, 42);
+}
+
+TEST(QuotaCommon_TryInspect, SameScopeDecl)
+{
+  QM_TRY_INSPECT(const int32_t& x, (Result<int32_t, nsresult>{42}), QM_VOID);
+  EXPECT_EQ(x, 42);
+
+  QM_TRY_INSPECT(const int32_t& y, (Result<int32_t, nsresult>{42}), QM_VOID);
+  EXPECT_EQ(y, 42);
+}
+
+TEST(QuotaCommon_TryInspect, SameLine)
+{
+  // clang-format off
+  QM_TRY_INSPECT(const auto &x, (Result<int32_t, nsresult>{42}), QM_VOID); QM_TRY_INSPECT(const auto &y, (Result<int32_t, nsresult>{42}), QM_VOID);
+  // clang-format on
+
+  EXPECT_EQ(x, 42);
+  EXPECT_EQ(y, 42);
+}
+
+TEST(QuotaCommon_TryInspect, NestingMadness_Success)
+{
+  bool nestedTryInspectDidNotReturn = false;
+  bool tryInspectDidNotReturn = false;
+
+  nsresult rv = [&nestedTryInspectDidNotReturn,
+                 &tryInspectDidNotReturn]() -> nsresult {
+    QM_TRY_INSPECT(
+        const auto& x,
+        ([&nestedTryInspectDidNotReturn]() -> Result<int32_t, nsresult> {
+          QM_TRY_INSPECT(const auto& x, (Result<int32_t, nsresult>{42}));
+
+          nestedTryInspectDidNotReturn = true;
+
+          return x;
+        }()));
+    EXPECT_EQ(x, 42);
+
+    tryInspectDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_TRUE(nestedTryInspectDidNotReturn);
+  EXPECT_TRUE(tryInspectDidNotReturn);
+  EXPECT_EQ(rv, NS_OK);
+}
+
+TEST(QuotaCommon_TryInspect, NestingMadness_Failure)
+{
+  bool nestedTryInspectDidNotReturn = false;
+  bool tryInspectDidNotReturn = false;
+
+  nsresult rv = [&nestedTryInspectDidNotReturn,
+                 &tryInspectDidNotReturn]() -> nsresult {
+    QM_TRY_INSPECT(
+        const auto& x,
+        ([&nestedTryInspectDidNotReturn]() -> Result<int32_t, nsresult> {
+          QM_TRY_INSPECT(const auto& x,
+                         (Result<int32_t, nsresult>{Err(NS_ERROR_FAILURE)}));
+
+          nestedTryInspectDidNotReturn = true;
+
+          return x;
+        }()));
+    Unused << x;
+
+    tryInspectDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_FALSE(nestedTryInspectDidNotReturn);
+  EXPECT_FALSE(tryInspectDidNotReturn);
+  EXPECT_EQ(rv, NS_ERROR_FAILURE);
+}
+
+TEST(QuotaCommon_TryInspect, NestingMadness_Multiple_Success)
+{
+  bool nestedTryInspect1DidNotReturn = false;
+  bool nestedTryInspect2DidNotReturn = false;
+  bool tryInspectDidNotReturn = false;
+
+  nsresult rv = [&nestedTryInspect1DidNotReturn, &nestedTryInspect2DidNotReturn,
+                 &tryInspectDidNotReturn]() -> nsresult {
+    QM_TRY_INSPECT(
+        const auto& z,
+        ([&nestedTryInspect1DidNotReturn,
+          &nestedTryInspect2DidNotReturn]() -> Result<int32_t, nsresult> {
+          QM_TRY_INSPECT(const auto& x, (Result<int32_t, nsresult>{42}));
+
+          nestedTryInspect1DidNotReturn = true;
+
+          QM_TRY_INSPECT(const auto& y, (Result<int32_t, nsresult>{42}));
+
+          nestedTryInspect2DidNotReturn = true;
+
+          return x + y;
+        }()));
+    EXPECT_EQ(z, 84);
+
+    tryInspectDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_TRUE(nestedTryInspect1DidNotReturn);
+  EXPECT_TRUE(nestedTryInspect2DidNotReturn);
+  EXPECT_TRUE(tryInspectDidNotReturn);
+  EXPECT_EQ(rv, NS_OK);
+}
+
+TEST(QuotaCommon_TryInspect, NestingMadness_Multiple_Failure1)
+{
+  bool nestedTryInspect1DidNotReturn = false;
+  bool nestedTryInspect2DidNotReturn = false;
+  bool tryInspectDidNotReturn = false;
+
+  nsresult rv = [&nestedTryInspect1DidNotReturn, &nestedTryInspect2DidNotReturn,
+                 &tryInspectDidNotReturn]() -> nsresult {
+    QM_TRY_INSPECT(
+        const auto& z,
+        ([&nestedTryInspect1DidNotReturn,
+          &nestedTryInspect2DidNotReturn]() -> Result<int32_t, nsresult> {
+          QM_TRY_INSPECT(const auto& x,
+                         (Result<int32_t, nsresult>{Err(NS_ERROR_FAILURE)}));
+
+          nestedTryInspect1DidNotReturn = true;
+
+          QM_TRY_INSPECT(const auto& y, (Result<int32_t, nsresult>{42}));
+
+          nestedTryInspect2DidNotReturn = true;
+
+          return x + y;
+        }()));
+    Unused << z;
+
+    tryInspectDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_FALSE(nestedTryInspect1DidNotReturn);
+  EXPECT_FALSE(nestedTryInspect2DidNotReturn);
+  EXPECT_FALSE(tryInspectDidNotReturn);
+  EXPECT_EQ(rv, NS_ERROR_FAILURE);
+}
+
+TEST(QuotaCommon_TryInspect, NestingMadness_Multiple_Failure2)
+{
+  bool nestedTryInspect1DidNotReturn = false;
+  bool nestedTryInspect2DidNotReturn = false;
+  bool tryInspectDidNotReturn = false;
+
+  nsresult rv = [&nestedTryInspect1DidNotReturn, &nestedTryInspect2DidNotReturn,
+                 &tryInspectDidNotReturn]() -> nsresult {
+    QM_TRY_INSPECT(
+        const auto& z,
+        ([&nestedTryInspect1DidNotReturn,
+          &nestedTryInspect2DidNotReturn]() -> Result<int32_t, nsresult> {
+          QM_TRY_INSPECT(const auto& x, (Result<int32_t, nsresult>{42}));
+
+          nestedTryInspect1DidNotReturn = true;
+
+          QM_TRY_INSPECT(const auto& y,
+                         (Result<int32_t, nsresult>{Err(NS_ERROR_FAILURE)}));
+
+          nestedTryInspect2DidNotReturn = true;
+
+          return x + y;
+        }()));
+    Unused << z;
+
+    tryInspectDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_TRUE(nestedTryInspect1DidNotReturn);
+  EXPECT_FALSE(nestedTryInspect2DidNotReturn);
+  EXPECT_FALSE(tryInspectDidNotReturn);
+  EXPECT_EQ(rv, NS_ERROR_FAILURE);
+}
+
+// We are not repeating all QM_TRY_INSPECT test cases for QM_TRY_UNWRAP, since
+// they are largely based on the same implementation. We just add some where
+// inspecting and unwrapping differ.
+
+TEST(QuotaCommon_TryUnwrap, NonConstDecl)
+{
+  QM_TRY_UNWRAP(int32_t x, (Result<int32_t, nsresult>{42}), QM_VOID);
+
+  static_assert(std::is_same_v<decltype(x), int32_t>);
+
+  EXPECT_EQ(x, 42);
+}
+
+TEST(QuotaCommon_TryUnwrap, RvalueDecl)
+{
+  QM_TRY_UNWRAP(int32_t && x, (Result<int32_t, nsresult>{42}), QM_VOID);
+
+  static_assert(std::is_same_v<decltype(x), int32_t&&>);
+
+  EXPECT_EQ(x, 42);
+}
+
+TEST(QuotaCommon_TryUnwrap, ParenDecl)
+{
+  QM_TRY_UNWRAP(
+      (auto&& [x, y]),
+      (Result<std::pair<int32_t, bool>, nsresult>{std::pair{42, true}}),
+      QM_VOID);
+
+  static_assert(std::is_same_v<decltype(x), int32_t>);
+  static_assert(std::is_same_v<decltype(y), bool>);
+
+  EXPECT_EQ(x, 42);
+  EXPECT_EQ(y, true);
+}
+
+TEST(QuotaCommon_TryReturn, Success)
+{
+  bool tryReturnDidNotReturn = false;
+
+  auto res = [&tryReturnDidNotReturn] {
+    QM_TRY_RETURN((Result<int32_t, nsresult>{42}));
+
+    tryReturnDidNotReturn = true;
+  }();
+
+  EXPECT_FALSE(tryReturnDidNotReturn);
+  EXPECT_TRUE(res.isOk());
+  EXPECT_EQ(res.unwrap(), 42);
+}
+
+TEST(QuotaCommon_TryReturn, Success_nsresult)
+{
+  bool tryReturnDidNotReturn = false;
+
+  auto res = [&tryReturnDidNotReturn] {
+    QM_TRY_RETURN(MOZ_TO_RESULT(NS_OK));
+
+    tryReturnDidNotReturn = true;
+  }();
+
+  EXPECT_FALSE(tryReturnDidNotReturn);
+  EXPECT_TRUE(res.isOk());
+}
+
+#ifdef DEBUG
+TEST(QuotaCommon_TryReturn, Success_CustomErr_AssertUnreachable)
+{
+  bool tryReturnDidNotReturn = false;
+
+  auto res = [&tryReturnDidNotReturn]() -> Result<int32_t, nsresult> {
+    QM_TRY_RETURN((Result<int32_t, nsresult>{42}), QM_ASSERT_UNREACHABLE);
+
+    tryReturnDidNotReturn = true;
+  }();
+
+  EXPECT_FALSE(tryReturnDidNotReturn);
+  EXPECT_TRUE(res.isOk());
+  EXPECT_EQ(res.unwrap(), 42);
+}
+#endif
+
+TEST(QuotaCommon_TryReturn, Success_CustomErr_CustomLambda)
+{
+#define SUBTEST(...)                                                \
+  {                                                                 \
+    bool tryReturnDidNotReturn = false;                             \
+                                                                    \
+    auto res = [&tryReturnDidNotReturn]() -> Result<Ok, nsresult> { \
+      QM_TRY_RETURN(MOZ_TO_RESULT(NS_OK),                           \
+                    [](__VA_ARGS__) { return Err(aRv); });          \
+                                                                    \
+      tryReturnDidNotReturn = true;                                 \
+    }();                                                            \
+                                                                    \
+    EXPECT_FALSE(tryReturnDidNotReturn);                            \
+    EXPECT_TRUE(res.isOk());                                        \
+  }
+
+  SUBTEST(const char*, nsresult aRv);
+  SUBTEST(nsresult aRv);
+
+#undef SUBTEST
+}
+
+TEST(QuotaCommon_TryReturn, Success_WithCleanup)
+{
+  bool tryReturnCleanupRan = false;
+  bool tryReturnDidNotReturn = false;
+
+  auto res = [&tryReturnCleanupRan,
+              &tryReturnDidNotReturn]() -> Result<int32_t, nsresult> {
+    QM_TRY_RETURN(
+        (Result<int32_t, nsresult>{42}), QM_PROPAGATE,
+        [&tryReturnCleanupRan](const auto&) { tryReturnCleanupRan = true; });
+
+    tryReturnDidNotReturn = true;
+  }();
+
+  EXPECT_FALSE(tryReturnCleanupRan);
+  EXPECT_FALSE(tryReturnDidNotReturn);
+  EXPECT_TRUE(res.isOk());
+  EXPECT_EQ(res.unwrap(), 42);
+}
+
+TEST(QuotaCommon_TryReturn, Failure_PropagateErr)
+{
+  bool tryReturnDidNotReturn = false;
+
+  auto res = [&tryReturnDidNotReturn] {
+    QM_TRY_RETURN((Result<int32_t, nsresult>{Err(NS_ERROR_FAILURE)}));
+
+    tryReturnDidNotReturn = true;
+  }();
+
+  EXPECT_FALSE(tryReturnDidNotReturn);
+  EXPECT_TRUE(res.isErr());
+  EXPECT_EQ(res.unwrapErr(), NS_ERROR_FAILURE);
+}
+
+TEST(QuotaCommon_TryReturn, Failure_PropagateErr_nsresult)
+{
+  bool tryReturnDidNotReturn = false;
+
+  auto res = [&tryReturnDidNotReturn] {
+    QM_TRY_RETURN(MOZ_TO_RESULT(NS_ERROR_FAILURE));
+
+    tryReturnDidNotReturn = true;
+  }();
+
+  EXPECT_FALSE(tryReturnDidNotReturn);
+  EXPECT_TRUE(res.isErr());
+  EXPECT_EQ(res.unwrapErr(), NS_ERROR_FAILURE);
+}
+
+TEST(QuotaCommon_TryReturn, Failure_CustomErr)
+{
+  bool tryReturnDidNotReturn = false;
+
+  auto res = [&tryReturnDidNotReturn]() -> Result<int32_t, nsresult> {
+    QM_TRY_RETURN((Result<int32_t, nsresult>{Err(NS_ERROR_FAILURE)}),
+                  Err(NS_ERROR_UNEXPECTED));
+
+    tryReturnDidNotReturn = true;
+  }();
+
+  EXPECT_FALSE(tryReturnDidNotReturn);
+  EXPECT_TRUE(res.isErr());
+  EXPECT_EQ(res.unwrapErr(), NS_ERROR_UNEXPECTED);
+}
+
+TEST(QuotaCommon_TryReturn, Failure_CustomErr_CustomLambda)
+{
+#define SUBTEST(...)                                                       \
+  {                                                                        \
+    bool tryReturnDidNotReturn = false;                                    \
+                                                                           \
+    auto res = [&tryReturnDidNotReturn]() -> Result<int32_t, nsresult> {   \
+      QM_TRY_RETURN((Result<int32_t, nsresult>{Err(NS_ERROR_FAILURE)}),    \
+                    [](__VA_ARGS__) { return Err(NS_ERROR_UNEXPECTED); }); \
+                                                                           \
+      tryReturnDidNotReturn = true;                                        \
+    }();                                                                   \
+                                                                           \
+    EXPECT_FALSE(tryReturnDidNotReturn);                                   \
+    EXPECT_TRUE(res.isErr());                                              \
+    EXPECT_EQ(res.unwrapErr(), NS_ERROR_UNEXPECTED);                       \
+  }
+
+  SUBTEST(const char*, nsresult);
+  SUBTEST(nsresult);
+
+#undef SUBTEST
+}
+
+TEST(QuotaCommon_TryReturn, Failure_WithCleanup)
+{
+  bool tryReturnCleanupRan = false;
+  bool tryReturnDidNotReturn = false;
+
+  auto res = [&tryReturnCleanupRan,
+              &tryReturnDidNotReturn]() -> Result<int32_t, nsresult> {
+    QM_TRY_RETURN((Result<int32_t, nsresult>{Err(NS_ERROR_FAILURE)}),
+                  QM_PROPAGATE, [&tryReturnCleanupRan](const auto& result) {
+                    EXPECT_EQ(result, NS_ERROR_FAILURE);
+
+                    tryReturnCleanupRan = true;
+                  });
+
+    tryReturnDidNotReturn = true;
+  }();
+
+  EXPECT_TRUE(tryReturnCleanupRan);
+  EXPECT_FALSE(tryReturnDidNotReturn);
+  EXPECT_TRUE(res.isErr());
+  EXPECT_EQ(res.unwrapErr(), NS_ERROR_FAILURE);
+}
+
+TEST(QuotaCommon_TryReturn, SameLine)
+{
+  // clang-format off
+  auto res1 = [] { QM_TRY_RETURN((Result<int32_t, nsresult>{42})); }(); auto res2 = []() -> Result<int32_t, nsresult> { QM_TRY_RETURN((Result<int32_t, nsresult>{42})); }();
+  // clang-format on
+
+  EXPECT_TRUE(res1.isOk());
+  EXPECT_EQ(res1.unwrap(), 42);
+  EXPECT_TRUE(res2.isOk());
+  EXPECT_EQ(res2.unwrap(), 42);
+}
+
+TEST(QuotaCommon_TryReturn, NestingMadness_Success)
+{
+  bool nestedTryReturnDidNotReturn = false;
+  bool tryReturnDidNotReturn = false;
+
+  auto res = [&nestedTryReturnDidNotReturn, &tryReturnDidNotReturn] {
+    QM_TRY_RETURN(([&nestedTryReturnDidNotReturn] {
+      QM_TRY_RETURN((Result<int32_t, nsresult>{42}));
+
+      nestedTryReturnDidNotReturn = true;
+    }()));
+
+    tryReturnDidNotReturn = true;
+  }();
+
+  EXPECT_FALSE(nestedTryReturnDidNotReturn);
+  EXPECT_FALSE(tryReturnDidNotReturn);
+  EXPECT_TRUE(res.isOk());
+  EXPECT_EQ(res.unwrap(), 42);
+}
+
+TEST(QuotaCommon_TryReturn, NestingMadness_Failure)
+{
+  bool nestedTryReturnDidNotReturn = false;
+  bool tryReturnDidNotReturn = false;
+
+  auto res = [&nestedTryReturnDidNotReturn, &tryReturnDidNotReturn] {
+    QM_TRY_RETURN(([&nestedTryReturnDidNotReturn] {
+      QM_TRY_RETURN((Result<int32_t, nsresult>{Err(NS_ERROR_FAILURE)}));
+
+      nestedTryReturnDidNotReturn = true;
+    }()));
+
+    tryReturnDidNotReturn = true;
+  }();
+
+  EXPECT_FALSE(nestedTryReturnDidNotReturn);
+  EXPECT_FALSE(tryReturnDidNotReturn);
+  EXPECT_TRUE(res.isErr());
+  EXPECT_EQ(res.unwrapErr(), NS_ERROR_FAILURE);
+}
+
+TEST(QuotaCommon_Fail, ReturnValue)
+{
+  bool failDidNotReturn = false;
+
+  nsresult rv = [&failDidNotReturn]() -> nsresult {
+    QM_FAIL(NS_ERROR_FAILURE);
+
+    failDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_FALSE(failDidNotReturn);
+  EXPECT_EQ(rv, NS_ERROR_FAILURE);
+}
+
+TEST(QuotaCommon_Fail, ReturnValue_WithCleanup)
+{
+  bool failCleanupRan = false;
+  bool failDidNotReturn = false;
+
+  nsresult rv = [&failCleanupRan, &failDidNotReturn]() -> nsresult {
+    QM_FAIL(NS_ERROR_FAILURE, [&failCleanupRan]() { failCleanupRan = true; });
+
+    failDidNotReturn = true;
+
+    return NS_OK;
+  }();
+
+  EXPECT_TRUE(failCleanupRan);
+  EXPECT_FALSE(failDidNotReturn);
+  EXPECT_EQ(rv, NS_ERROR_FAILURE);
+}
+
+TEST(QuotaCommon_WarnOnlyTry, Success)
+{
+  bool warnOnlyTryDidNotReturn = false;
+
+  const auto res =
+      [&warnOnlyTryDidNotReturn]() -> mozilla::Result<mozilla::Ok, NotOk> {
+    QM_WARNONLY_TRY(OkIf(true));
+
+    warnOnlyTryDidNotReturn = true;
+    return mozilla::Ok{};
+  }();
+
+  EXPECT_TRUE(res.isOk());
+  EXPECT_TRUE(warnOnlyTryDidNotReturn);
+}
+
+TEST(QuotaCommon_WarnOnlyTry, Success_WithCleanup)
+{
+  bool warnOnlyTryCleanupRan = false;
+  bool warnOnlyTryDidNotReturn = false;
+
+  const auto res =
+      [&warnOnlyTryCleanupRan,
+       &warnOnlyTryDidNotReturn]() -> mozilla::Result<mozilla::Ok, NotOk> {
+    QM_WARNONLY_TRY(OkIf(true), [&warnOnlyTryCleanupRan](const auto&) {
+      warnOnlyTryCleanupRan = true;
+    });
+
+    warnOnlyTryDidNotReturn = true;
+    return mozilla::Ok{};
+  }();
+
+  EXPECT_TRUE(res.isOk());
+  EXPECT_FALSE(warnOnlyTryCleanupRan);
+  EXPECT_TRUE(warnOnlyTryDidNotReturn);
+}
+
+TEST(QuotaCommon_WarnOnlyTry, Failure)
+{
+  bool warnOnlyTryDidNotReturn = false;
+
+  const auto res =
+      [&warnOnlyTryDidNotReturn]() -> mozilla::Result<mozilla::Ok, NotOk> {
+    QM_WARNONLY_TRY(OkIf(false));
+
+    warnOnlyTryDidNotReturn = true;
+    return mozilla::Ok{};
+  }();
+
+  EXPECT_TRUE(res.isOk());
+  EXPECT_TRUE(warnOnlyTryDidNotReturn);
+}
+
+TEST(QuotaCommon_WarnOnlyTry, Failure_WithCleanup)
+{
+  bool warnOnlyTryCleanupRan = false;
+  bool warnOnlyTryDidNotReturn = false;
+
+  const auto res =
+      [&warnOnlyTryCleanupRan,
+       &warnOnlyTryDidNotReturn]() -> mozilla::Result<mozilla::Ok, NotOk> {
+    QM_WARNONLY_TRY(OkIf(false), ([&warnOnlyTryCleanupRan](const auto&) {
+                      warnOnlyTryCleanupRan = true;
+                    }));
+
+    warnOnlyTryDidNotReturn = true;
+    return mozilla::Ok{};
+  }();
+
+  EXPECT_TRUE(res.isOk());
+  EXPECT_TRUE(warnOnlyTryCleanupRan);
+  EXPECT_TRUE(warnOnlyTryDidNotReturn);
+}
+
+TEST(QuotaCommon_WarnOnlyTryUnwrap, Success)
+{
+  bool warnOnlyTryUnwrapDidNotReturn = false;
+
+  const auto res = [&warnOnlyTryUnwrapDidNotReturn]()
+      -> mozilla::Result<mozilla::Ok, NotOk> {
+    QM_WARNONLY_TRY_UNWRAP(const auto x, (Result<int32_t, NotOk>{42}));
+    EXPECT_TRUE(x);
+    EXPECT_EQ(*x, 42);
+
+    warnOnlyTryUnwrapDidNotReturn = true;
+    return mozilla::Ok{};
+  }();
+
+  EXPECT_TRUE(res.isOk());
+  EXPECT_TRUE(warnOnlyTryUnwrapDidNotReturn);
+}
+
+TEST(QuotaCommon_WarnOnlyTryUnwrap, Success_WithCleanup)
+{
+  bool warnOnlyTryUnwrapCleanupRan = false;
+  bool warnOnlyTryUnwrapDidNotReturn = false;
+
+  const auto res = [&warnOnlyTryUnwrapCleanupRan,
+                    &warnOnlyTryUnwrapDidNotReturn]()
+      -> mozilla::Result<mozilla::Ok, NotOk> {
+    QM_WARNONLY_TRY_UNWRAP(const auto x, (Result<int32_t, NotOk>{42}),
+                           [&warnOnlyTryUnwrapCleanupRan](const auto&) {
+                             warnOnlyTryUnwrapCleanupRan = true;
+                           });
+    EXPECT_TRUE(x);
+    EXPECT_EQ(*x, 42);
+
+    warnOnlyTryUnwrapDidNotReturn = true;
+    return mozilla::Ok{};
+  }();
+
+  EXPECT_TRUE(res.isOk());
+  EXPECT_FALSE(warnOnlyTryUnwrapCleanupRan);
+  EXPECT_TRUE(warnOnlyTryUnwrapDidNotReturn);
+}
+
+TEST(QuotaCommon_WarnOnlyTryUnwrap, Failure)
+{
+  bool warnOnlyTryUnwrapDidNotReturn = false;
+
+  const auto res = [&warnOnlyTryUnwrapDidNotReturn]()
+      -> mozilla::Result<mozilla::Ok, NotOk> {
+    QM_WARNONLY_TRY_UNWRAP(const auto x,
+                           (Result<int32_t, NotOk>{Err(NotOk{})}));
+    EXPECT_FALSE(x);
+
+    warnOnlyTryUnwrapDidNotReturn = true;
+    return mozilla::Ok{};
+  }();
+
+  EXPECT_TRUE(res.isOk());
+  EXPECT_TRUE(warnOnlyTryUnwrapDidNotReturn);
+}
+
+TEST(QuotaCommon_WarnOnlyTryUnwrap, Failure_WithCleanup)
+{
+  bool warnOnlyTryUnwrapCleanupRan = false;
+  bool warnOnlyTryUnwrapDidNotReturn = false;
+
+  const auto res = [&warnOnlyTryUnwrapCleanupRan,
+                    &warnOnlyTryUnwrapDidNotReturn]()
+      -> mozilla::Result<mozilla::Ok, NotOk> {
+    QM_WARNONLY_TRY_UNWRAP(const auto x, (Result<int32_t, NotOk>{Err(NotOk{})}),
+                           [&warnOnlyTryUnwrapCleanupRan](const auto&) {
+                             warnOnlyTryUnwrapCleanupRan = true;
+                           });
+    EXPECT_FALSE(x);
+
+    warnOnlyTryUnwrapDidNotReturn = true;
+    return mozilla::Ok{};
+  }();
+
+  EXPECT_TRUE(res.isOk());
+  EXPECT_TRUE(warnOnlyTryUnwrapCleanupRan);
+  EXPECT_TRUE(warnOnlyTryUnwrapDidNotReturn);
+}
+
+TEST(QuotaCommon_OrElseWarn, Success)
+{
+  bool fallbackRun = false;
+  bool tryContinued = false;
+
+  const auto res = [&]() -> mozilla::Result<mozilla::Ok, NotOk> {
+    QM_TRY(QM_OR_ELSE_WARN(OkIf(true), ([&fallbackRun](const NotOk) {
+                             fallbackRun = true;
+                             return mozilla::Result<mozilla::Ok, NotOk>{
+                                 mozilla::Ok{}};
+                           })));
+
+    tryContinued = true;
+    return mozilla::Ok{};
+  }();
+
+  EXPECT_TRUE(res.isOk());
+  EXPECT_FALSE(fallbackRun);
+  EXPECT_TRUE(tryContinued);
+}
+
+TEST(QuotaCommon_OrElseWarn, Failure_MappedToSuccess)
+{
+  bool fallbackRun = false;
+  bool tryContinued = false;
+
+  // XXX Consider allowing to set a custom error handler, so that we can
+  // actually assert that a warning was emitted.
+  const auto res = [&]() -> mozilla::Result<mozilla::Ok, NotOk> {
+    QM_TRY(QM_OR_ELSE_WARN(OkIf(false), ([&fallbackRun](const NotOk) {
+                             fallbackRun = true;
+                             return mozilla::Result<mozilla::Ok, NotOk>{
+                                 mozilla::Ok{}};
+                           })));
+    tryContinued = true;
+    return mozilla::Ok{};
+  }();
+
+  EXPECT_TRUE(res.isOk());
+  EXPECT_TRUE(fallbackRun);
+  EXPECT_TRUE(tryContinued);
+}
+
+TEST(QuotaCommon_OrElseWarn, Failure_MappedToError)
+{
+  bool fallbackRun = false;
+  bool tryContinued = false;
+
+  // XXX Consider allowing to set a custom error handler, so that we can
+  // actually assert that a warning was emitted.
+  const auto res = [&]() -> mozilla::Result<mozilla::Ok, NotOk> {
+    QM_TRY(QM_OR_ELSE_WARN(OkIf(false), ([&fallbackRun](const NotOk) {
+                             fallbackRun = true;
+                             return mozilla::Result<mozilla::Ok, NotOk>{
+                                 NotOk{}};
+                           })));
+    tryContinued = true;
+    return mozilla::Ok{};
+  }();
+
+  EXPECT_TRUE(res.isErr());
+  EXPECT_TRUE(fallbackRun);
+  EXPECT_FALSE(tryContinued);
+}
+
+TEST(QuotaCommon_OrElseWarnIf, Success)
+{
+  bool predicateRun = false;
+  bool fallbackRun = false;
+  bool tryContinued = false;
+
+  const auto res = [&]() -> mozilla::Result<mozilla::Ok, NotOk> {
+    QM_TRY(QM_OR_ELSE_WARN_IF(
+        OkIf(true),
+        [&predicateRun](const NotOk) {
+          predicateRun = true;
+          return false;
+        },
+        ([&fallbackRun](const NotOk) {
+          fallbackRun = true;
+          return mozilla::Result<mozilla::Ok, NotOk>{mozilla::Ok{}};
+        })));
+
+    tryContinued = true;
+    return mozilla::Ok{};
+  }();
+
+  EXPECT_TRUE(res.isOk());
+  EXPECT_FALSE(predicateRun);
+  EXPECT_FALSE(fallbackRun);
+  EXPECT_TRUE(tryContinued);
+}
+
+TEST(QuotaCommon_OrElseWarnIf, Failure_PredicateReturnsFalse)
+{
+  bool predicateRun = false;
+  bool fallbackRun = false;
+  bool tryContinued = false;
+
+  const auto res = [&]() -> mozilla::Result<mozilla::Ok, NotOk> {
+    QM_TRY(QM_OR_ELSE_WARN_IF(
+        OkIf(false),
+        [&predicateRun](const NotOk) {
+          predicateRun = true;
+          return false;
+        },
+        ([&fallbackRun](const NotOk) {
+          fallbackRun = true;
+          return mozilla::Result<mozilla::Ok, NotOk>{mozilla::Ok{}};
+        })));
+
+    tryContinued = true;
+    return mozilla::Ok{};
+  }();
+
+  EXPECT_TRUE(res.isErr());
+  EXPECT_TRUE(predicateRun);
+  EXPECT_FALSE(fallbackRun);
+  EXPECT_FALSE(tryContinued);
+}
+
+TEST(QuotaCommon_OrElseWarnIf, Failure_PredicateReturnsTrue_MappedToSuccess)
+{
+  bool predicateRun = false;
+  bool fallbackRun = false;
+  bool tryContinued = false;
+
+  const auto res = [&]() -> mozilla::Result<mozilla::Ok, NotOk> {
+    QM_TRY(QM_OR_ELSE_WARN_IF(
+        OkIf(false),
+        [&predicateRun](const NotOk) {
+          predicateRun = true;
+          return true;
+        },
+        ([&fallbackRun](const NotOk) {
+          fallbackRun = true;
+          return mozilla::Result<mozilla::Ok, NotOk>{mozilla::Ok{}};
+        })));
+
+    tryContinued = true;
+    return mozilla::Ok{};
+  }();
+
+  EXPECT_TRUE(res.isOk());
+  EXPECT_TRUE(predicateRun);
+  EXPECT_TRUE(fallbackRun);
+  EXPECT_TRUE(tryContinued);
+}
+
+TEST(QuotaCommon_OrElseWarnIf, Failure_PredicateReturnsTrue_MappedToError)
+{
+  bool predicateRun = false;
+  bool fallbackRun = false;
+  bool tryContinued = false;
+
+  const auto res = [&]() -> mozilla::Result<mozilla::Ok, NotOk> {
+    QM_TRY(QM_OR_ELSE_WARN_IF(
+        OkIf(false),
+        [&predicateRun](const NotOk) {
+          predicateRun = true;
+          return true;
+        },
+        ([&fallbackRun](const NotOk) {
+          fallbackRun = true;
+          return mozilla::Result<mozilla::Ok, NotOk>{mozilla::NotOk{}};
+        })));
+
+    tryContinued = true;
+    return mozilla::Ok{};
+  }();
+
+  EXPECT_TRUE(res.isErr());
+  EXPECT_TRUE(predicateRun);
+  EXPECT_TRUE(fallbackRun);
+  EXPECT_FALSE(tryContinued);
+}
+
+TEST(QuotaCommon_OkIf, True)
+{
+  auto res = OkIf(true);
+
+  EXPECT_TRUE(res.isOk());
+}
+
+TEST(QuotaCommon_OkIf, False)
+{
+  auto res = OkIf(false);
+
+  EXPECT_TRUE(res.isErr());
+}
+
+TEST(QuotaCommon_OkToOk, Bool_True)
+{
+  auto res = OkToOk<true>(Ok());
+  EXPECT_TRUE(res.isOk());
+  EXPECT_EQ(res.unwrap(), true);
+}
+
+TEST(QuotaCommon_OkToOk, Bool_False)
+{
+  auto res = OkToOk<false>(Ok());
+  EXPECT_TRUE(res.isOk());
+  EXPECT_EQ(res.unwrap(), false);
+}
+
+TEST(QuotaCommon_OkToOk, Int_42)
+{
+  auto res = OkToOk<42>(Ok());
+  EXPECT_TRUE(res.isOk());
+  EXPECT_EQ(res.unwrap(), 42);
+}
+
+TEST(QuotaCommon_ErrToOkOrErr, Bool_True)
+{
+  auto res = ErrToOkOrErr<NS_ERROR_FAILURE, true>(NS_ERROR_FAILURE);
+  EXPECT_TRUE(res.isOk());
+  EXPECT_EQ(res.unwrap(), true);
+}
+
+TEST(QuotaCommon_ErrToOkOrErr, Bool_True_Err)
+{
+  auto res = ErrToOkOrErr<NS_ERROR_FAILURE, true>(NS_ERROR_UNEXPECTED);
+  EXPECT_TRUE(res.isErr());
+  EXPECT_EQ(res.unwrapErr(), NS_ERROR_UNEXPECTED);
+}
+
+TEST(QuotaCommon_ErrToOkOrErr, Bool_False)
+{
+  auto res = ErrToOkOrErr<NS_ERROR_FAILURE, false>(NS_ERROR_FAILURE);
+  EXPECT_TRUE(res.isOk());
+  EXPECT_EQ(res.unwrap(), false);
+}
+
+TEST(QuotaCommon_ErrToOkOrErr, Bool_False_Err)
+{
+  auto res = ErrToOkOrErr<NS_ERROR_FAILURE, false>(NS_ERROR_UNEXPECTED);
+  EXPECT_TRUE(res.isErr());
+  EXPECT_EQ(res.unwrapErr(), NS_ERROR_UNEXPECTED);
+}
+
+TEST(QuotaCommon_ErrToOkOrErr, Int_42)
+{
+  auto res = ErrToOkOrErr<NS_ERROR_FAILURE, 42>(NS_ERROR_FAILURE);
+  EXPECT_TRUE(res.isOk());
+  EXPECT_EQ(res.unwrap(), 42);
+}
+
+TEST(QuotaCommon_ErrToOkOrErr, Int_42_Err)
+{
+  auto res = ErrToOkOrErr<NS_ERROR_FAILURE, 42>(NS_ERROR_UNEXPECTED);
+  EXPECT_TRUE(res.isErr());
+  EXPECT_EQ(res.unwrapErr(), NS_ERROR_UNEXPECTED);
+}
+
+TEST(QuotaCommon_ErrToOkOrErr, NsCOMPtr_nullptr)
+{
+  auto res = ErrToOkOrErr<NS_ERROR_FAILURE, nullptr, nsCOMPtr<nsISupports>>(
+      NS_ERROR_FAILURE);
+  EXPECT_TRUE(res.isOk());
+  EXPECT_EQ(res.unwrap(), nullptr);
+}
+
+TEST(QuotaCommon_ErrToOkOrErr, NsCOMPtr_nullptr_Err)
+{
+  auto res = ErrToOkOrErr<NS_ERROR_FAILURE, nullptr, nsCOMPtr<nsISupports>>(
+      NS_ERROR_UNEXPECTED);
+  EXPECT_TRUE(res.isErr());
+  EXPECT_EQ(res.unwrapErr(), NS_ERROR_UNEXPECTED);
+}
+
+TEST(QuotaCommon_ErrToDefaultOkOrErr, Ok)
+{
+  auto res = ErrToDefaultOkOrErr<NS_ERROR_FAILURE, Ok>(NS_ERROR_FAILURE);
+  EXPECT_TRUE(res.isOk());
+}
+
+TEST(QuotaCommon_ErrToDefaultOkOrErr, Ok_Err)
+{
+  auto res = ErrToDefaultOkOrErr<NS_ERROR_FAILURE, Ok>(NS_ERROR_UNEXPECTED);
+  EXPECT_TRUE(res.isErr());
+  EXPECT_EQ(res.unwrapErr(), NS_ERROR_UNEXPECTED);
+}
+
+TEST(QuotaCommon_ErrToDefaultOkOrErr, NsCOMPtr)
+{
+  auto res = ErrToDefaultOkOrErr<NS_ERROR_FAILURE, nsCOMPtr<nsISupports>>(
+      NS_ERROR_FAILURE);
+  EXPECT_TRUE(res.isOk());
+  EXPECT_EQ(res.unwrap(), nullptr);
+}
+
+TEST(QuotaCommon_ErrToDefaultOkOrErr, NsCOMPtr_Err)
+{
+  auto res = ErrToDefaultOkOrErr<NS_ERROR_FAILURE, nsCOMPtr<nsISupports>>(
+      NS_ERROR_UNEXPECTED);
+  EXPECT_TRUE(res.isErr());
+  EXPECT_EQ(res.unwrapErr(), NS_ERROR_UNEXPECTED);
+}
+
+TEST(QuotaCommon_IsSpecificError, Match)
+{ EXPECT_TRUE(IsSpecificError<NS_ERROR_FAILURE>(NS_ERROR_FAILURE)); }
+
+TEST(QuotaCommon_IsSpecificError, Mismatch)
+{ EXPECT_FALSE(IsSpecificError<NS_ERROR_FAILURE>(NS_ERROR_UNEXPECTED)); }
+
+TEST(QuotaCommon_ErrToOk, Bool_True)
+{
+  auto res = ErrToOk<true>(NS_ERROR_FAILURE);
+  EXPECT_TRUE(res.isOk());
+  EXPECT_EQ(res.unwrap(), true);
+}
+
+TEST(QuotaCommon_ErrToOk, Bool_False)
+{
+  auto res = ErrToOk<false>(NS_ERROR_FAILURE);
+  EXPECT_TRUE(res.isOk());
+  EXPECT_EQ(res.unwrap(), false);
+}
+
+TEST(QuotaCommon_ErrToOk, Int_42)
+{
+  auto res = ErrToOk<42>(NS_ERROR_FAILURE);
+  EXPECT_TRUE(res.isOk());
+  EXPECT_EQ(res.unwrap(), 42);
+}
+
+TEST(QuotaCommon_ErrToOk, NsCOMPtr_nullptr)
+{
+  auto res = ErrToOk<nullptr, nsCOMPtr<nsISupports>>(NS_ERROR_FAILURE);
+  EXPECT_TRUE(res.isOk());
+  EXPECT_EQ(res.unwrap(), nullptr);
+}
+
+TEST(QuotaCommon_ErrToDefaultOk, Ok)
+{
+  auto res = ErrToDefaultOk<Ok>(NS_ERROR_FAILURE);
+  EXPECT_TRUE(res.isOk());
+}
+
+TEST(QuotaCommon_ErrToDefaultOk, NsCOMPtr)
+{
+  auto res = ErrToDefaultOk<nsCOMPtr<nsISupports>>(NS_ERROR_FAILURE);
+  EXPECT_TRUE(res.isOk());
+  EXPECT_EQ(res.unwrap(), nullptr);
+}
+
+class StringPairParameterized
+    : public ::testing::TestWithParam<std::pair<const char*, const char*>> {};
+
+TEST_P(StringPairParameterized, AnonymizedOriginString) {
+  const auto [in, expectedAnonymized] = GetParam();
+  const auto anonymized = AnonymizedOriginString(nsDependentCString(in));
+  EXPECT_STREQ(anonymized.get(), expectedAnonymized);
+}
+
+INSTANTIATE_TEST_SUITE_P(
+    QuotaCommon, StringPairParameterized,
+    ::testing::Values(
+        // XXX Do we really want to anonymize about: origins?
+        std::pair("about:home", "about:aaaa"),
+        std::pair("https://foo.bar.com", "https://aaa.aaa.aaa"),
+        std::pair("https://foo.bar.com:8000", "https://aaa.aaa.aaa:DDDD"),
+        std::pair("file://UNIVERSAL_FILE_ORIGIN",
+                  "file://aaaaaaaaa_aaaa_aaaaaa")));
+
+// BEGIN COPY FROM mfbt/tests/TestResult.cpp
+struct Failed {};
+
+static GenericErrorResult<Failed> Fail() { return Err(Failed()); }
+
+static Result<Ok, Failed> Task1(bool pass) {
+  if (!pass) {
+    return Fail();  // implicit conversion from GenericErrorResult to Result
+  }
+  return Ok();
+}
+// END COPY FROM mfbt/tests/TestResult.cpp
+
+static Result<bool, Failed> Condition(bool aNoError, bool aResult) {
+  return Task1(aNoError).map([aResult](auto) { return aResult; });
+}
+
+TEST(QuotaCommon_CollectWhileTest, NoFailures)
+{
+  const size_t loopCount = 5;
+  size_t conditionExecutions = 0;
+  size_t bodyExecutions = 0;
+  auto result = CollectWhile(
+      [&conditionExecutions] {
+        ++conditionExecutions;
+        return Condition(true, conditionExecutions <= loopCount);
+      },
+      [&bodyExecutions] {
+        ++bodyExecutions;
+        return Task1(true);
+      });
+  static_assert(std::is_same_v<decltype(result), Result<Ok, Failed>>);
+  MOZ_RELEASE_ASSERT(result.isOk());
+  MOZ_RELEASE_ASSERT(loopCount == bodyExecutions);
+  MOZ_RELEASE_ASSERT(1 + loopCount == conditionExecutions);
+}
+
+TEST(QuotaCommon_CollectWhileTest, BodyFailsImmediately)
+{
+  size_t conditionExecutions = 0;
+  size_t bodyExecutions = 0;
+  auto result = CollectWhile(
+      [&conditionExecutions] {
+        ++conditionExecutions;
+        return Condition(true, true);
+      },
+      [&bodyExecutions] {
+        ++bodyExecutions;
+        return Task1(false);
+      });
+  static_assert(std::is_same_v<decltype(result), Result<Ok, Failed>>);
+  MOZ_RELEASE_ASSERT(result.isErr());
+  MOZ_RELEASE_ASSERT(1 == bodyExecutions);
+  MOZ_RELEASE_ASSERT(1 == conditionExecutions);
+}
+
+TEST(QuotaCommon_CollectWhileTest, BodyFailsOnSecondExecution)
+{
+  size_t conditionExecutions = 0;
+  size_t bodyExecutions = 0;
+  auto result = CollectWhile(
+      [&conditionExecutions] {
+        ++conditionExecutions;
+        return Condition(true, true);
+      },
+      [&bodyExecutions] {
+        ++bodyExecutions;
+        return Task1(bodyExecutions < 2);
+      });
+  static_assert(std::is_same_v<decltype(result), Result<Ok, Failed>>);
+  MOZ_RELEASE_ASSERT(result.isErr());
+  MOZ_RELEASE_ASSERT(2 == bodyExecutions);
+  MOZ_RELEASE_ASSERT(2 == conditionExecutions);
+}
+
+TEST(QuotaCommon_CollectWhileTest, ConditionFailsImmediately)
+{
+  size_t conditionExecutions = 0;
+  size_t bodyExecutions = 0;
+  auto result = CollectWhile(
+      [&conditionExecutions] {
+        ++conditionExecutions;
+        return Condition(false, true);
+      },
+      [&bodyExecutions] {
+        ++bodyExecutions;
+        return Task1(true);
+      });
+  static_assert(std::is_same_v<decltype(result), Result<Ok, Failed>>);
+  MOZ_RELEASE_ASSERT(result.isErr());
+  MOZ_RELEASE_ASSERT(0 == bodyExecutions);
+  MOZ_RELEASE_ASSERT(1 == conditionExecutions);
+}
+
+TEST(QuotaCommon_CollectWhileTest, ConditionFailsOnSecondExecution)
+{
+  size_t conditionExecutions = 0;
+  size_t bodyExecutions = 0;
+  auto result = CollectWhile(
+      [&conditionExecutions] {
+        ++conditionExecutions;
+        return Condition(conditionExecutions < 2, true);
+      },
+      [&bodyExecutions] {
+        ++bodyExecutions;
+        return Task1(true);
+      });
+  static_assert(std::is_same_v<decltype(result), Result<Ok, Failed>>);
+  MOZ_RELEASE_ASSERT(result.isErr());
+  MOZ_RELEASE_ASSERT(1 == bodyExecutions);
+  MOZ_RELEASE_ASSERT(2 == conditionExecutions);
+}
+
+TEST(QuotaCommon_CollectEachInRange, Success)
+{
+  size_t bodyExecutions = 0;
+  const auto result = CollectEachInRange(
+      std::array<int, 5>{{1, 2, 3, 4, 5}},
+      [&bodyExecutions](const int val) -> Result<Ok, nsresult> {
+        ++bodyExecutions;
+        return Ok{};
+      });
+
+  MOZ_RELEASE_ASSERT(result.isOk());
+  MOZ_RELEASE_ASSERT(5 == bodyExecutions);
+}
+
+TEST(QuotaCommon_CollectEachInRange, FailureShortCircuit)
+{
+  size_t bodyExecutions = 0;
+  const auto result = CollectEachInRange(
+      std::array<int, 5>{{1, 2, 3, 4, 5}},
+      [&bodyExecutions](const int val) -> Result<Ok, nsresult> {
+        ++bodyExecutions;
+        return val == 3 ? Err(NS_ERROR_FAILURE) : Result<Ok, nsresult>{Ok{}};
+      });
+
+  MOZ_RELEASE_ASSERT(result.isErr());
+  MOZ_RELEASE_ASSERT(NS_ERROR_FAILURE == result.inspectErr());
+  MOZ_RELEASE_ASSERT(3 == bodyExecutions);
+}
+
+TEST(QuotaCommon_ReduceEach, Success)
+{
+  const auto result = ReduceEach(
+      [i = int{0}]() mutable -> Result<int, Failed> {
+        if (i < 5) {
+          return ++i;
+        }
+        return 0;
+      },
+      0, [](int val, int add) -> Result<int, Failed> { return val + add; });
+  static_assert(std::is_same_v<decltype(result), const Result<int, Failed>>);
+
+  MOZ_RELEASE_ASSERT(result.isOk());
+  MOZ_RELEASE_ASSERT(15 == result.inspect());
+}
+
+TEST(QuotaCommon_ReduceEach, StepError)
+{
+  const auto result = ReduceEach(
+      [i = int{0}]() mutable -> Result<int, Failed> {
+        if (i < 5) {
+          return ++i;
+        }
+        return 0;
+      },
+      0,
+      [](int val, int add) -> Result<int, Failed> {
+        if (val > 2) {
+          return Err(Failed{});
+        }
+        return val + add;
+      });
+  static_assert(std::is_same_v<decltype(result), const Result<int, Failed>>);
+
+  MOZ_RELEASE_ASSERT(result.isErr());
+}
+
+TEST(QuotaCommon_ReduceEach, GeneratorError)
+{
+  size_t generatorExecutions = 0;
+  const auto result = ReduceEach(
+      [i = int{0}, &generatorExecutions]() mutable -> Result<int, Failed> {
+        ++generatorExecutions;
+        if (i < 1) {
+          return ++i;
+        }
+        return Err(Failed{});
+      },
+      0,
+      [](int val, int add) -> Result<int, Failed> {
+        if (val > 2) {
+          return Err(Failed{});
+        }
+        return val + add;
+      });
+  static_assert(std::is_same_v<decltype(result), const Result<int, Failed>>);
+
+  MOZ_RELEASE_ASSERT(result.isErr());
+  MOZ_RELEASE_ASSERT(2 == generatorExecutions);
+}
+
+TEST(QuotaCommon_Reduce, Success)
+{
+  const auto range = std::vector{0, 1, 2, 3, 4, 5};
+  const auto result = Reduce(
+      range, 0, [](int val, Maybe<const int&> add) -> Result<int, Failed> {
+        return val + add.ref();
+      });
+  static_assert(std::is_same_v<decltype(result), const Result<int, Failed>>);
+
+  MOZ_RELEASE_ASSERT(result.isOk());
+  MOZ_RELEASE_ASSERT(15 == result.inspect());
+}
+
+TEST(QuotaCommon_CallWithDelayedRetriesIfAccessDenied, NoFailures)
+{
+  uint32_t tries = 0;
+
+  auto res = CallWithDelayedRetriesIfAccessDenied(
+      [&tries]() -> Result<Ok, nsresult> {
+        ++tries;
+        return Ok{};
+      },
+      10, 2);
+
+  EXPECT_EQ(tries, 1u);
+  EXPECT_TRUE(res.isOk());
+}
+
+TEST(QuotaCommon_CallWithDelayedRetriesIfAccessDenied, PermanentFailures)
+{
+  uint32_t tries = 0;
+
+  auto res = CallWithDelayedRetriesIfAccessDenied(
+      [&tries]() -> Result<Ok, nsresult> {
+        ++tries;
+        return Err(NS_ERROR_FILE_IS_LOCKED);
+      },
+      10, 2);
+
+  EXPECT_EQ(tries, 11u);
+  EXPECT_TRUE(res.isErr());
+}
+
+TEST(QuotaCommon_CallWithDelayedRetriesIfAccessDenied, FailuresAndSuccess)
+{
+  uint32_t tries = 0;
+
+  auto res = CallWithDelayedRetriesIfAccessDenied(
+      [&tries]() -> Result<Ok, nsresult> {
+        if (++tries == 5) {
+          return Ok{};
+        }
+        return Err(NS_ERROR_FILE_ACCESS_DENIED);
+      },
+      10, 2);
+
+  EXPECT_EQ(tries, 5u);
+  EXPECT_TRUE(res.isOk());
+}
+
+TEST(QuotaCommon_MakeSourceFileRelativePath, ThisSourceFile)
+{
+  static constexpr auto thisSourceFileRelativePath =
+      "dom/quota/test/gtest/TestQuotaCommon.cpp"_ns;
+
+  const nsCString sourceFileRelativePath{
+      mozilla::dom::quota::detail::MakeSourceFileRelativePath(
+          nsLiteralCString(__FILE__))};
+
+  EXPECT_STREQ(sourceFileRelativePath.get(), thisSourceFileRelativePath.get());
+}
+
+static nsCString MakeTreePath(const nsACString& aBasePath,
+                              const nsACString& aRelativePath) {
+  nsCString path{aBasePath};
+
+  path.Append("/");
+  path.Append(aRelativePath);
+
+  return path;
+}
+
+static nsCString MakeSourceTreePath(const nsACString& aRelativePath) {
+  return MakeTreePath(mozilla::dom::quota::detail::GetSourceTreeBase(),
+                      aRelativePath);
+}
+
+static nsCString MakeObjdirDistIncludeTreePath(
+    const nsACString& aRelativePath) {
+  return MakeTreePath(
+      mozilla::dom::quota::detail::GetObjdirDistIncludeTreeBase(),
+      aRelativePath);
+}
+
+TEST(QuotaCommon_MakeSourceFileRelativePath, DomQuotaSourceFile)
+{
+  static constexpr auto domQuotaSourceFileRelativePath =
+      "dom/quota/ActorsParent.cpp"_ns;
+
+  const nsCString sourceFileRelativePath{
+      mozilla::dom::quota::detail::MakeSourceFileRelativePath(
+          MakeSourceTreePath(domQuotaSourceFileRelativePath))};
+
+  EXPECT_STREQ(sourceFileRelativePath.get(),
+               domQuotaSourceFileRelativePath.get());
+}
+
+TEST(QuotaCommon_MakeSourceFileRelativePath, DomQuotaSourceFile_Exported)
+{
+  static constexpr auto mozillaDomQuotaSourceFileRelativePath =
+      "mozilla/dom/quota/QuotaCommon.h"_ns;
+
+  static constexpr auto domQuotaSourceFileRelativePath =
+      "dom/quota/QuotaCommon.h"_ns;
+
+  const nsCString sourceFileRelativePath{
+      mozilla::dom::quota::detail::MakeSourceFileRelativePath(
+          MakeObjdirDistIncludeTreePath(
+              mozillaDomQuotaSourceFileRelativePath))};
+
+  EXPECT_STREQ(sourceFileRelativePath.get(),
+               domQuotaSourceFileRelativePath.get());
+}
+
+TEST(QuotaCommon_MakeSourceFileRelativePath, DomIndexedDBSourceFile)
+{
+  static constexpr auto domIndexedDBSourceFileRelativePath =
+      "dom/indexedDB/ActorsParent.cpp"_ns;
+
+  const nsCString sourceFileRelativePath{
+      mozilla::dom::quota::detail::MakeSourceFileRelativePath(
+          MakeSourceTreePath(domIndexedDBSourceFileRelativePath))};
+
+  EXPECT_STREQ(sourceFileRelativePath.get(),
+               domIndexedDBSourceFileRelativePath.get());
+}
+
+TEST(QuotaCommon_MakeSourceFileRelativePath,
+     DomLocalstorageSourceFile_Exported_Mapped)
+{
+  static constexpr auto mozillaDomSourceFileRelativePath =
+      "mozilla/dom/LocalStorageCommon.h"_ns;
+
+  static constexpr auto domLocalstorageSourceFileRelativePath =
+      "dom/localstorage/LocalStorageCommon.h"_ns;
+
+  const nsCString sourceFileRelativePath{
+      mozilla::dom::quota::detail::MakeSourceFileRelativePath(
+          MakeObjdirDistIncludeTreePath(mozillaDomSourceFileRelativePath))};
+
+  EXPECT_STREQ(sourceFileRelativePath.get(),
+               domLocalstorageSourceFileRelativePath.get());
+}
+
+TEST(QuotaCommon_MakeSourceFileRelativePath, NonDomSourceFile)
+{
+  static constexpr auto nonDomSourceFileRelativePath =
+      "storage/mozStorageService.cpp"_ns;
+
+  const nsCString sourceFileRelativePath{
+      mozilla::dom::quota::detail::MakeSourceFileRelativePath(
+          MakeSourceTreePath(nonDomSourceFileRelativePath))};
+
+  EXPECT_STREQ(sourceFileRelativePath.get(),
+               nonDomSourceFileRelativePath.get());
+}
+
+TEST(QuotaCommon_MakeSourceFileRelativePath, OtherSourceFile)
+{
+  constexpr auto otherSourceFilePath = "/foo/bar/Test.cpp"_ns;
+  const nsCString sourceFileRelativePath{
+      mozilla::dom::quota::detail::MakeSourceFileRelativePath(
+          otherSourceFilePath)};
+
+  EXPECT_STREQ(sourceFileRelativePath.get(), "Test.cpp");
+}
+
+#ifdef __clang__
+#  pragma clang diagnostic pop
+#endif
+
+}  // namespace mozilla::dom::quota
diff --git a/dom/quota/test/gtest/TestQuotaManager.cpp b/dom/quota/test/gtest/TestQuotaManager.cpp
new file mode 100644
index 0000000000..c93f18ca61
--- /dev/null
+++ b/dom/quota/test/gtest/TestQuotaManager.cpp
@@ -0,0 +1,1611 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gtest/gtest.h"
+#include "mozilla/SpinEventLoopUntil.h"
+#include "mozilla/dom/quota/DirectoryLock.h"
+#include "mozilla/dom/quota/OriginScope.h"
+#include "mozilla/dom/quota/QuotaManager.h"
+#include "mozilla/gtest/MozAssertions.h"
+#include "QuotaManagerDependencyFixture.h"
+
+namespace mozilla::dom::quota::test {
+
+class TestQuotaManager : public QuotaManagerDependencyFixture {
+ public:
+  static void SetUpTestCase() { ASSERT_NO_FATAL_FAILURE(InitializeFixture()); }
+
+  static void TearDownTestCase() { ASSERT_NO_FATAL_FAILURE(ShutdownFixture()); }
+};
+
+// Test OpenStorageDirectory when an opening of the storage directory is
+// already ongoing and storage shutdown is scheduled after that.
+TEST_F(TestQuotaManager, OpenStorageDirectory_OngoingWithScheduledShutdown) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    RefPtr<UniversalDirectoryLock> directoryLock;
+
+    nsTArray<RefPtr<BoolPromise>> promises;
+
+    promises.AppendElement(
+        quotaManager
+            ->OpenStorageDirectory(
+                Nullable<PersistenceType>(PERSISTENCE_TYPE_PERSISTENT),
+                OriginScope::FromNull(), Nullable<Client::Type>(),
+                /* aExclusive */ false)
+            ->Then(GetCurrentSerialEventTarget(), __func__,
+                   [&directoryLock](
+                       UniversalDirectoryLockPromise::ResolveOrRejectValue&&
+                           aValue) {
+                     if (aValue.IsReject()) {
+                       return BoolPromise::CreateAndReject(aValue.RejectValue(),
+                                                           __func__);
+                     }
+
+                     [&aValue]() { ASSERT_TRUE(aValue.ResolveValue()); }();
+
+                     directoryLock = std::move(aValue.ResolveValue());
+
+                     return BoolPromise::CreateAndResolve(true, __func__);
+                   })
+            ->Then(quotaManager->IOThread(), __func__,
+                   [](const BoolPromise::ResolveOrRejectValue& aValue) {
+                     if (aValue.IsReject()) {
+                       return BoolPromise::CreateAndReject(aValue.RejectValue(),
+                                                           __func__);
+                     }
+
+                     []() {
+                       QuotaManager* quotaManager = QuotaManager::Get();
+                       ASSERT_TRUE(quotaManager);
+
+                       ASSERT_TRUE(
+                           quotaManager->IsStorageInitializedInternal());
+                     }();
+
+                     return BoolPromise::CreateAndResolve(true, __func__);
+                   })
+            ->Then(GetCurrentSerialEventTarget(), __func__,
+                   [&directoryLock](
+                       const BoolPromise::ResolveOrRejectValue& aValue) {
+                     directoryLock = nullptr;
+
+                     if (aValue.IsReject()) {
+                       return BoolPromise::CreateAndReject(aValue.RejectValue(),
+                                                           __func__);
+                     }
+
+                     return BoolPromise::CreateAndResolve(true, __func__);
+                   }));
+    promises.AppendElement(quotaManager->ShutdownStorage());
+    promises.AppendElement(
+        quotaManager
+            ->OpenStorageDirectory(
+                Nullable<PersistenceType>(PERSISTENCE_TYPE_PERSISTENT),
+                OriginScope::FromNull(), Nullable<Client::Type>(),
+                /* aExclusive */ false)
+            ->Then(GetCurrentSerialEventTarget(), __func__,
+                   [](const UniversalDirectoryLockPromise::ResolveOrRejectValue&
+                          aValue) {
+                     if (aValue.IsReject()) {
+                       return BoolPromise::CreateAndReject(aValue.RejectValue(),
+                                                           __func__);
+                     }
+
+                     return BoolPromise::CreateAndResolve(true, __func__);
+                   }));
+
+    bool done = false;
+
+    BoolPromise::All(GetCurrentSerialEventTarget(), promises)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const CopyableTArray<bool>& aResolveValues) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+              done = true;
+            },
+            [&done](nsresult aRejectValue) {
+              ASSERT_TRUE(false);
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+// Test OpenStorageDirectory when an opening of the storage directory is
+// already ongoing and an exclusive directory lock is requested after that.
+TEST_F(TestQuotaManager,
+       OpenStorageDirectory_OngoingWithExclusiveDirectoryLock) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    RefPtr<UniversalDirectoryLock> directoryLock =
+        quotaManager->CreateDirectoryLockInternal(Nullable<PersistenceType>(),
+                                                  OriginScope::FromNull(),
+                                                  Nullable<Client::Type>(),
+                                                  /* aExclusive */ true);
+
+    nsTArray<RefPtr<BoolPromise>> promises;
+
+    promises.AppendElement(
+        quotaManager
+            ->OpenStorageDirectory(
+                Nullable<PersistenceType>(PERSISTENCE_TYPE_PERSISTENT),
+                OriginScope::FromNull(), Nullable<Client::Type>(),
+                /* aExclusive */ false)
+            ->Then(
+                GetCurrentSerialEventTarget(), __func__,
+                [&directoryLock](
+                    const UniversalDirectoryLockPromise::ResolveOrRejectValue&
+                        aValue) {
+                  directoryLock = nullptr;
+
+                  if (aValue.IsReject()) {
+                    return BoolPromise::CreateAndReject(aValue.RejectValue(),
+                                                        __func__);
+                  }
+
+                  return BoolPromise::CreateAndResolve(true, __func__);
+                }));
+    promises.AppendElement(directoryLock->Acquire());
+    promises.AppendElement(
+        quotaManager
+            ->OpenStorageDirectory(
+                Nullable<PersistenceType>(PERSISTENCE_TYPE_PERSISTENT),
+                OriginScope::FromNull(), Nullable<Client::Type>(),
+                /* aExclusive */ false)
+            ->Then(GetCurrentSerialEventTarget(), __func__,
+                   [](const UniversalDirectoryLockPromise::ResolveOrRejectValue&
+                          aValue) {
+                     if (aValue.IsReject()) {
+                       return BoolPromise::CreateAndReject(aValue.RejectValue(),
+                                                           __func__);
+                     }
+
+                     return BoolPromise::CreateAndResolve(true, __func__);
+                   }));
+
+    bool done = false;
+
+    BoolPromise::All(GetCurrentSerialEventTarget(), promises)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const CopyableTArray<bool>& aResolveValues) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+              done = true;
+            },
+            [&done](nsresult aRejectValue) {
+              ASSERT_TRUE(false);
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+// Test OpenStorageDirectory when an opening of the storage directory already
+// finished.
+TEST_F(TestQuotaManager, OpenStorageDirectory_Finished) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    bool done = false;
+
+    quotaManager
+        ->OpenStorageDirectory(
+            Nullable<PersistenceType>(PERSISTENCE_TYPE_PERSISTENT),
+            OriginScope::FromNull(), Nullable<Client::Type>(),
+            /* aExclusive */ false)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const UniversalDirectoryLockPromise::ResolveOrRejectValue&
+                        aValue) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+
+    done = false;
+
+    quotaManager
+        ->OpenStorageDirectory(
+            Nullable<PersistenceType>(PERSISTENCE_TYPE_PERSISTENT),
+            OriginScope::FromNull(), Nullable<Client::Type>(),
+            /* aExclusive */ false)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const UniversalDirectoryLockPromise::ResolveOrRejectValue&
+                        aValue) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+// Test OpenStorageDirectory when an opening of the storage directory already
+// finished but storage shutdown has just been scheduled.
+TEST_F(TestQuotaManager, OpenStorageDirectory_FinishedWithScheduledShutdown) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    bool done = false;
+
+    quotaManager
+        ->OpenStorageDirectory(
+            Nullable<PersistenceType>(PERSISTENCE_TYPE_PERSISTENT),
+            OriginScope::FromNull(), Nullable<Client::Type>(),
+            /* aExclusive */ false)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const UniversalDirectoryLockPromise::ResolveOrRejectValue&
+                        aValue) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+
+    nsTArray<RefPtr<BoolPromise>> promises;
+
+    promises.AppendElement(quotaManager->ShutdownStorage());
+    promises.AppendElement(
+        quotaManager
+            ->OpenStorageDirectory(
+                Nullable<PersistenceType>(PERSISTENCE_TYPE_PERSISTENT),
+                OriginScope::FromNull(), Nullable<Client::Type>(),
+                /* aExclusive */ false)
+            ->Then(GetCurrentSerialEventTarget(), __func__,
+                   [](const UniversalDirectoryLockPromise::ResolveOrRejectValue&
+                          aValue) {
+                     if (aValue.IsReject()) {
+                       return BoolPromise::CreateAndReject(aValue.RejectValue(),
+                                                           __func__);
+                     }
+
+                     return BoolPromise::CreateAndResolve(true, __func__);
+                   }));
+
+    done = false;
+
+    BoolPromise::All(GetCurrentSerialEventTarget(), promises)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const CopyableTArray<bool>& aResolveValues) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+              done = true;
+            },
+            [&done](nsresult aRejectValue) {
+              ASSERT_TRUE(false);
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+// Test OpenStorageDirectory when an opening of the storage directory already
+// finished and an exclusive client directory lock for a non-overlapping
+// origin is acquired in between.
+TEST_F(TestQuotaManager,
+       OpenStorageDirectory_FinishedWithExclusiveClientDirectoryLock) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    bool done = false;
+
+    quotaManager
+        ->OpenStorageDirectory(
+            Nullable<PersistenceType>(PERSISTENCE_TYPE_PERSISTENT),
+            OriginScope::FromNull(), Nullable<Client::Type>(),
+            /* aExclusive */ false)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const UniversalDirectoryLockPromise::ResolveOrRejectValue&
+                        aValue) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+
+    RefPtr<ClientDirectoryLock> directoryLock =
+        quotaManager->CreateDirectoryLock(GetTestClientMetadata(),
+                                          /* aExclusive */ true);
+
+    done = false;
+
+    directoryLock->Acquire()->Then(
+        GetCurrentSerialEventTarget(), __func__,
+        [&done](const BoolPromise::ResolveOrRejectValue& aValue) {
+          done = true;
+        });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+
+    done = false;
+
+    quotaManager
+        ->OpenStorageDirectory(
+            Nullable<PersistenceType>(PERSISTENCE_TYPE_PERSISTENT),
+            OriginScope::FromNull(), Nullable<Client::Type>(),
+            /* aExclusive */ false)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const UniversalDirectoryLockPromise::ResolveOrRejectValue&
+                        aValue) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+// Test OpenClientDirctory when an opening of a client directory is already
+// ongoing and storage shutdown is scheduled after that.
+TEST_F(TestQuotaManager, OpenClientDirectory_OngoingWithScheduledShutdown) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    RefPtr<ClientDirectoryLock> directoryLock;
+
+    nsTArray<RefPtr<BoolPromise>> promises;
+
+    promises.AppendElement(
+        quotaManager->OpenClientDirectory(GetTestClientMetadata())
+            ->Then(
+                GetCurrentSerialEventTarget(), __func__,
+                [&directoryLock](
+                    ClientDirectoryLockPromise::ResolveOrRejectValue&& aValue) {
+                  if (aValue.IsReject()) {
+                    return BoolPromise::CreateAndReject(aValue.RejectValue(),
+                                                        __func__);
+                  }
+
+                  [&aValue]() { ASSERT_TRUE(aValue.ResolveValue()); }();
+
+                  directoryLock = std::move(aValue.ResolveValue());
+
+                  return BoolPromise::CreateAndResolve(true, __func__);
+                })
+            ->Then(quotaManager->IOThread(), __func__,
+                   [](const BoolPromise::ResolveOrRejectValue& aValue) {
+                     if (aValue.IsReject()) {
+                       return BoolPromise::CreateAndReject(aValue.RejectValue(),
+                                                           __func__);
+                     }
+
+                     []() {
+                       QuotaManager* quotaManager = QuotaManager::Get();
+                       ASSERT_TRUE(quotaManager);
+
+                       ASSERT_TRUE(
+                           quotaManager->IsStorageInitializedInternal());
+                     }();
+
+                     return BoolPromise::CreateAndResolve(true, __func__);
+                   })
+            ->Then(GetCurrentSerialEventTarget(), __func__,
+                   [&directoryLock](
+                       const BoolPromise::ResolveOrRejectValue& aValue) {
+                     directoryLock = nullptr;
+
+                     if (aValue.IsReject()) {
+                       return BoolPromise::CreateAndReject(aValue.RejectValue(),
+                                                           __func__);
+                     }
+
+                     return BoolPromise::CreateAndResolve(true, __func__);
+                   }));
+    promises.AppendElement(quotaManager->ShutdownStorage());
+    promises.AppendElement(
+        quotaManager->OpenClientDirectory(GetTestClientMetadata())
+            ->Then(GetCurrentSerialEventTarget(), __func__,
+                   [](const ClientDirectoryLockPromise::ResolveOrRejectValue&
+                          aValue) {
+                     if (aValue.IsReject()) {
+                       return BoolPromise::CreateAndReject(aValue.RejectValue(),
+                                                           __func__);
+                     }
+
+                     return BoolPromise::CreateAndResolve(true, __func__);
+                   }));
+
+    bool done = false;
+
+    BoolPromise::All(GetCurrentSerialEventTarget(), promises)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const CopyableTArray<bool>& aResolveValues) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+              done = true;
+            },
+            [&done](nsresult aRejectValue) {
+              ASSERT_TRUE(false);
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+// Test OpenClientDirectory when an opening of a client directory is already
+// ongoing and an exclusive directory lock is requested after that.
+TEST_F(TestQuotaManager,
+       OpenClientDirectory_OngoingWithExclusiveDirectoryLock) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    RefPtr<UniversalDirectoryLock> directoryLock =
+        quotaManager->CreateDirectoryLockInternal(Nullable<PersistenceType>(),
+                                                  OriginScope::FromNull(),
+                                                  Nullable<Client::Type>(),
+                                                  /* aExclusive */ true);
+
+    nsTArray<RefPtr<BoolPromise>> promises;
+
+    promises.AppendElement(
+        quotaManager->OpenClientDirectory(GetTestClientMetadata())
+            ->Then(GetCurrentSerialEventTarget(), __func__,
+                   [&directoryLock](
+                       const ClientDirectoryLockPromise::ResolveOrRejectValue&
+                           aValue) {
+                     directoryLock = nullptr;
+
+                     if (aValue.IsReject()) {
+                       return BoolPromise::CreateAndReject(aValue.RejectValue(),
+                                                           __func__);
+                     }
+
+                     return BoolPromise::CreateAndResolve(true, __func__);
+                   }));
+    promises.AppendElement(directoryLock->Acquire());
+    promises.AppendElement(
+        quotaManager->OpenClientDirectory(GetTestClientMetadata())
+            ->Then(GetCurrentSerialEventTarget(), __func__,
+                   [](const ClientDirectoryLockPromise::ResolveOrRejectValue&
+                          aValue) {
+                     if (aValue.IsReject()) {
+                       return BoolPromise::CreateAndReject(aValue.RejectValue(),
+                                                           __func__);
+                     }
+
+                     return BoolPromise::CreateAndResolve(true, __func__);
+                   }));
+
+    bool done = false;
+
+    BoolPromise::All(GetCurrentSerialEventTarget(), promises)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const CopyableTArray<bool>& aResolveValues) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+              done = true;
+            },
+            [&done](nsresult aRejectValue) {
+              ASSERT_TRUE(false);
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+// Test OpenClientDirectory when an opening of a client directory already
+// finished.
+TEST_F(TestQuotaManager, OpenClientDirectory_Finished) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    bool done = false;
+
+    quotaManager->OpenClientDirectory(GetTestClientMetadata())
+        ->Then(GetCurrentSerialEventTarget(), __func__,
+               [&done](const ClientDirectoryLockPromise::ResolveOrRejectValue&
+                           aValue) {
+                 QuotaManager* quotaManager = QuotaManager::Get();
+                 ASSERT_TRUE(quotaManager);
+
+                 ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+                 done = true;
+               });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+
+    done = false;
+
+    quotaManager->OpenClientDirectory(GetTestClientMetadata())
+        ->Then(GetCurrentSerialEventTarget(), __func__,
+               [&done](const ClientDirectoryLockPromise::ResolveOrRejectValue&
+                           aValue) {
+                 QuotaManager* quotaManager = QuotaManager::Get();
+                 ASSERT_TRUE(quotaManager);
+
+                 ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+                 done = true;
+               });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+// Test OpenClientDirectory when an opening of a client directory already
+// finished but storage shutdown has just been scheduled.
+TEST_F(TestQuotaManager, OpenClientDirectory_FinishedWithScheduledShutdown) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    bool done = false;
+
+    quotaManager->OpenClientDirectory(GetTestClientMetadata())
+        ->Then(GetCurrentSerialEventTarget(), __func__,
+               [&done](const ClientDirectoryLockPromise::ResolveOrRejectValue&
+                           aValue) {
+                 QuotaManager* quotaManager = QuotaManager::Get();
+                 ASSERT_TRUE(quotaManager);
+
+                 ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+                 done = true;
+               });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+
+    nsTArray<RefPtr<BoolPromise>> promises;
+
+    promises.AppendElement(quotaManager->ShutdownStorage());
+    promises.AppendElement(
+        quotaManager->OpenClientDirectory(GetTestClientMetadata())
+            ->Then(GetCurrentSerialEventTarget(), __func__,
+                   [](const ClientDirectoryLockPromise::ResolveOrRejectValue&
+                          aValue) {
+                     if (aValue.IsReject()) {
+                       return BoolPromise::CreateAndReject(aValue.RejectValue(),
+                                                           __func__);
+                     }
+
+                     return BoolPromise::CreateAndResolve(true, __func__);
+                   }));
+
+    done = false;
+
+    BoolPromise::All(GetCurrentSerialEventTarget(), promises)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const CopyableTArray<bool>& aResolveValues) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+              done = true;
+            },
+            [&done](nsresult aRejectValue) {
+              ASSERT_TRUE(false);
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+// Test OpenClientDirectory when an opening of a client directory already
+// finished with an exclusive client directory lock for a different origin is
+// acquired in between.
+TEST_F(TestQuotaManager,
+       OpenClientDirectory_FinishedWithOtherExclusiveClientDirectoryLock) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    bool done = false;
+
+    quotaManager->OpenClientDirectory(GetTestClientMetadata())
+        ->Then(GetCurrentSerialEventTarget(), __func__,
+               [&done](const ClientDirectoryLockPromise::ResolveOrRejectValue&
+                           aValue) {
+                 QuotaManager* quotaManager = QuotaManager::Get();
+                 ASSERT_TRUE(quotaManager);
+
+                 ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+                 done = true;
+               });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+
+    RefPtr<ClientDirectoryLock> directoryLock =
+        quotaManager->CreateDirectoryLock(GetOtherTestClientMetadata(),
+                                          /* aExclusive */ true);
+
+    done = false;
+
+    directoryLock->Acquire()->Then(
+        GetCurrentSerialEventTarget(), __func__,
+        [&done](const BoolPromise::ResolveOrRejectValue& aValue) {
+          done = true;
+        });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+
+    done = false;
+
+    quotaManager->OpenClientDirectory(GetTestClientMetadata())
+        ->Then(GetCurrentSerialEventTarget(), __func__,
+               [&done](const ClientDirectoryLockPromise::ResolveOrRejectValue&
+                           aValue) {
+                 QuotaManager* quotaManager = QuotaManager::Get();
+                 ASSERT_TRUE(quotaManager);
+
+                 ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+                 done = true;
+               });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+// Test simple InitializeStorage.
+TEST_F(TestQuotaManager, InitializeStorage_Simple) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    bool done = false;
+
+    quotaManager->InitializeStorage()->Then(
+        GetCurrentSerialEventTarget(), __func__,
+        [&done](const BoolPromise::ResolveOrRejectValue& aValue) {
+          QuotaManager* quotaManager = QuotaManager::Get();
+          ASSERT_TRUE(quotaManager);
+
+          ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+          done = true;
+        });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+// Test InitializeStorage when a storage initialization is already ongoing.
+TEST_F(TestQuotaManager, InitializeStorage_Ongoing) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    nsTArray<RefPtr<BoolPromise>> promises;
+
+    promises.AppendElement(quotaManager->InitializeStorage());
+    promises.AppendElement(quotaManager->InitializeStorage());
+
+    bool done = false;
+
+    BoolPromise::All(GetCurrentSerialEventTarget(), promises)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const CopyableTArray<bool>& aResolveValues) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+              done = true;
+            },
+            [&done](nsresult aRejectValue) {
+              ASSERT_TRUE(false);
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+// Test InitializeStorage when a storage initialization is already ongoing and
+// storage shutdown is scheduled after that.
+TEST_F(TestQuotaManager, InitializeStorage_OngoingWithScheduledShutdown) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    nsTArray<RefPtr<BoolPromise>> promises;
+
+    promises.AppendElement(quotaManager->InitializeStorage());
+    promises.AppendElement(quotaManager->ShutdownStorage());
+    promises.AppendElement(quotaManager->InitializeStorage());
+
+    bool done = false;
+
+    BoolPromise::All(GetCurrentSerialEventTarget(), promises)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const CopyableTArray<bool>& aResolveValues) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+              done = true;
+            },
+            [&done](nsresult aRejectValue) {
+              ASSERT_TRUE(false);
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+// Test InitializeStorage when a storage initialization is already ongoing and
+// an exclusive directory lock is requested after that.
+TEST_F(TestQuotaManager, InitializeStorage_OngoingWithExclusiveDirectoryLock) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    RefPtr<UniversalDirectoryLock> directoryLock =
+        quotaManager->CreateDirectoryLockInternal(Nullable<PersistenceType>(),
+                                                  OriginScope::FromNull(),
+                                                  Nullable<Client::Type>(),
+                                                  /* aExclusive */ true);
+
+    nsTArray<RefPtr<BoolPromise>> promises;
+
+    promises.AppendElement(quotaManager->InitializeStorage()->Then(
+        GetCurrentSerialEventTarget(), __func__,
+        [&directoryLock](const BoolPromise::ResolveOrRejectValue& aValue) {
+          // The exclusive directory lock must be released when the first
+          // storage initialization is finished, otherwise it would endlessly
+          // block the second storage initialization.
+          directoryLock = nullptr;
+
+          if (aValue.IsReject()) {
+            return BoolPromise::CreateAndReject(aValue.RejectValue(), __func__);
+          }
+
+          return BoolPromise::CreateAndResolve(true, __func__);
+        }));
+    promises.AppendElement(directoryLock->Acquire());
+    promises.AppendElement(quotaManager->InitializeStorage());
+
+    bool done = false;
+
+    BoolPromise::All(GetCurrentSerialEventTarget(), promises)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const CopyableTArray<bool>& aResolveValues) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+              done = true;
+            },
+            [&done](nsresult aRejectValue) {
+              ASSERT_TRUE(false);
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+// Test InitializeStorage when a storage initialization is already ongoing and
+// shared client directory locks are requested after that.
+// The shared client directory locks don't have to be released in this case.
+TEST_F(TestQuotaManager, InitializeStorage_OngoingWithClientDirectoryLocks) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    RefPtr<ClientDirectoryLock> directoryLock =
+        quotaManager->CreateDirectoryLock(GetTestClientMetadata(),
+                                          /* aExclusive */ false);
+
+    RefPtr<ClientDirectoryLock> directoryLock2 =
+        quotaManager->CreateDirectoryLock(GetTestClientMetadata(),
+                                          /* aExclusive */ false);
+
+    nsTArray<RefPtr<BoolPromise>> promises;
+
+    promises.AppendElement(quotaManager->InitializeStorage());
+    promises.AppendElement(directoryLock->Acquire());
+    promises.AppendElement(quotaManager->InitializeStorage());
+    promises.AppendElement(directoryLock2->Acquire());
+
+    bool done = false;
+
+    BoolPromise::All(GetCurrentSerialEventTarget(), promises)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const CopyableTArray<bool>& aResolveValues) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+              done = true;
+            },
+            [&done](nsresult aRejectValue) {
+              ASSERT_TRUE(false);
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+// Test InitializeStorage when a storage initialization is already ongoing and
+// shared client directory locks are requested after that with storage shutdown
+// scheduled in between.
+TEST_F(TestQuotaManager,
+       InitializeStorage_OngoingWithClientDirectoryLocksAndScheduledShutdown) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    RefPtr<ClientDirectoryLock> directoryLock =
+        quotaManager->CreateDirectoryLock(GetTestClientMetadata(),
+                                          /* aExclusive */ false);
+
+    directoryLock->OnInvalidate(
+        [&directoryLock]() { directoryLock = nullptr; });
+
+    RefPtr<ClientDirectoryLock> directoryLock2 =
+        quotaManager->CreateDirectoryLock(GetTestClientMetadata(),
+                                          /* aExclusive */ false);
+
+    nsTArray<RefPtr<BoolPromise>> promises;
+
+    promises.AppendElement(quotaManager->InitializeStorage());
+    promises.AppendElement(directoryLock->Acquire());
+    promises.AppendElement(quotaManager->ShutdownStorage());
+    promises.AppendElement(quotaManager->InitializeStorage());
+    promises.AppendElement(directoryLock2->Acquire());
+
+    bool done = false;
+
+    BoolPromise::All(GetCurrentSerialEventTarget(), promises)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const CopyableTArray<bool>& aResolveValues) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+              done = true;
+            },
+            [&done](nsresult aRejectValue) {
+              ASSERT_TRUE(false);
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+// Test InitializeStorage when a storage initialization already finished.
+TEST_F(TestQuotaManager, InitializeStorage_Finished) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    bool done = false;
+
+    quotaManager->InitializeStorage()->Then(
+        GetCurrentSerialEventTarget(), __func__,
+        [&done](const BoolPromise::ResolveOrRejectValue& aValue) {
+          QuotaManager* quotaManager = QuotaManager::Get();
+          ASSERT_TRUE(quotaManager);
+
+          ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+          done = true;
+        });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+
+    done = false;
+
+    quotaManager->InitializeStorage()->Then(
+        GetCurrentSerialEventTarget(), __func__,
+        [&done](const BoolPromise::ResolveOrRejectValue& aValue) {
+          QuotaManager* quotaManager = QuotaManager::Get();
+          ASSERT_TRUE(quotaManager);
+
+          ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+          done = true;
+        });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+// Test InitializeStorage when a storage initialization already finished but
+// storage shutdown has just been scheduled.
+TEST_F(TestQuotaManager, InitializeStorage_FinishedWithScheduledShutdown) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    bool done = false;
+
+    quotaManager->InitializeStorage()->Then(
+        GetCurrentSerialEventTarget(), __func__,
+        [&done](const BoolPromise::ResolveOrRejectValue& aValue) {
+          QuotaManager* quotaManager = QuotaManager::Get();
+          ASSERT_TRUE(quotaManager);
+
+          ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+          done = true;
+        });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+
+    nsTArray<RefPtr<BoolPromise>> promises;
+
+    promises.AppendElement(quotaManager->ShutdownStorage());
+    promises.AppendElement(quotaManager->InitializeStorage());
+
+    done = false;
+
+    BoolPromise::All(GetCurrentSerialEventTarget(), promises)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const CopyableTArray<bool>& aResolveValues) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+              done = true;
+            },
+            [&done](nsresult aRejectValue) {
+              ASSERT_TRUE(false);
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+// Test InitializeStorage when a storage initialization already finished and
+// shared client directory locks are requested immediately after requesting
+// storage initialization.
+TEST_F(TestQuotaManager, InitializeStorage_FinishedWithClientDirectoryLocks) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    RefPtr<ClientDirectoryLock> directoryLock =
+        quotaManager->CreateDirectoryLock(GetTestClientMetadata(),
+                                          /* aExclusive */ false);
+
+    nsTArray<RefPtr<BoolPromise>> promises;
+
+    promises.AppendElement(quotaManager->InitializeStorage());
+    promises.AppendElement(directoryLock->Acquire());
+
+    bool done = false;
+
+    BoolPromise::All(GetCurrentSerialEventTarget(), promises)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const CopyableTArray<bool>& aResolveValues) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+              done = true;
+            },
+            [&done](nsresult aRejectValue) {
+              ASSERT_TRUE(false);
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+
+    RefPtr<ClientDirectoryLock> directoryLock2 =
+        quotaManager->CreateDirectoryLock(GetTestClientMetadata(),
+                                          /* aExclusive */ false);
+
+    promises.Clear();
+
+    promises.AppendElement(quotaManager->InitializeStorage());
+    promises.AppendElement(directoryLock2->Acquire());
+
+    done = false;
+
+    BoolPromise::All(GetCurrentSerialEventTarget(), promises)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const CopyableTArray<bool>& aResolveValues) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+              done = true;
+            },
+            [&done](nsresult aRejectValue) {
+              ASSERT_TRUE(false);
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+// Test InitializeStorage when a storage initialization already finished and
+// shared client directory locks are requested immediatelly after requesting
+// storage initialization with storage shutdown performed in between.
+// The shared client directory lock is released when it gets invalidated by
+// storage shutdown which then unblocks the shutdown.
+TEST_F(TestQuotaManager,
+       InitializeStorage_FinishedWithClientDirectoryLocksAndScheduledShutdown) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    RefPtr<ClientDirectoryLock> directoryLock =
+        quotaManager->CreateDirectoryLock(GetTestClientMetadata(),
+                                          /* aExclusive */ false);
+
+    directoryLock->OnInvalidate(
+        [&directoryLock]() { directoryLock = nullptr; });
+
+    nsTArray<RefPtr<BoolPromise>> promises;
+
+    promises.AppendElement(quotaManager->InitializeStorage());
+    promises.AppendElement(directoryLock->Acquire());
+
+    bool done = false;
+
+    BoolPromise::All(GetCurrentSerialEventTarget(), promises)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const CopyableTArray<bool>& aResolveValues) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+              done = true;
+            },
+            [&done](nsresult aRejectValue) {
+              ASSERT_TRUE(false);
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+
+    done = false;
+
+    quotaManager->ShutdownStorage()->Then(
+        GetCurrentSerialEventTarget(), __func__,
+        [&done](const BoolPromise::ResolveOrRejectValue& aValue) {
+          QuotaManager* quotaManager = QuotaManager::Get();
+          ASSERT_TRUE(quotaManager);
+
+          ASSERT_FALSE(quotaManager->IsStorageInitialized());
+
+          done = true;
+        });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+
+    RefPtr<ClientDirectoryLock> directoryLock2 =
+        quotaManager->CreateDirectoryLock(GetTestClientMetadata(),
+                                          /* aExclusive */ false);
+
+    promises.Clear();
+
+    promises.AppendElement(quotaManager->InitializeStorage());
+    promises.AppendElement(directoryLock2->Acquire());
+
+    done = false;
+
+    BoolPromise::All(GetCurrentSerialEventTarget(), promises)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const CopyableTArray<bool>& aResolveValues) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_TRUE(quotaManager->IsStorageInitialized());
+
+              done = true;
+            },
+            [&done](nsresult aRejectValue) {
+              ASSERT_TRUE(false);
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+TEST_F(TestQuotaManager,
+       InitializeTemporaryStorage_FinishedWithScheduledShutdown) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  PerformOnBackgroundThread([]() {
+    nsTArray<RefPtr<BoolPromise>> promises;
+
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    promises.AppendElement(quotaManager->InitializeStorage());
+    promises.AppendElement(quotaManager->InitializeTemporaryStorage());
+
+    bool done = false;
+
+    BoolPromise::All(GetCurrentSerialEventTarget(), promises)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const CopyableTArray<bool>& aResolveValues) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_TRUE(quotaManager->IsStorageInitialized());
+              ASSERT_TRUE(quotaManager->IsTemporaryStorageInitialized());
+
+              done = true;
+            },
+            [&done](nsresult aRejectValue) {
+              ASSERT_TRUE(false);
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+
+    promises.Clear();
+
+    promises.AppendElement(quotaManager->ShutdownStorage());
+    promises.AppendElement(quotaManager->InitializeStorage());
+    promises.AppendElement(quotaManager->InitializeTemporaryStorage());
+
+    done = false;
+
+    BoolPromise::All(GetCurrentSerialEventTarget(), promises)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const CopyableTArray<bool>& aResolveValues) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_TRUE(quotaManager->IsStorageInitialized());
+              ASSERT_TRUE(quotaManager->IsTemporaryStorageInitialized());
+
+              done = true;
+            },
+            [&done](nsresult aRejectValue) {
+              ASSERT_TRUE(false);
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+// Test simple ShutdownStorage.
+TEST_F(TestQuotaManager, ShutdownStorage_Simple) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(InitializeStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    bool done = false;
+
+    quotaManager->ShutdownStorage()->Then(
+        GetCurrentSerialEventTarget(), __func__,
+        [&done](const BoolPromise::ResolveOrRejectValue& aValue) {
+          QuotaManager* quotaManager = QuotaManager::Get();
+          ASSERT_TRUE(quotaManager);
+
+          ASSERT_FALSE(quotaManager->IsStorageInitialized());
+
+          done = true;
+        });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+// Test ShutdownStorage when a storage shutdown is already ongoing.
+TEST_F(TestQuotaManager, ShutdownStorage_Ongoing) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(InitializeStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    nsTArray<RefPtr<BoolPromise>> promises;
+
+    promises.AppendElement(quotaManager->ShutdownStorage());
+    promises.AppendElement(quotaManager->ShutdownStorage());
+
+    bool done = false;
+
+    BoolPromise::All(GetCurrentSerialEventTarget(), promises)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const CopyableTArray<bool>& aResolveValues) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_FALSE(quotaManager->IsStorageInitialized());
+
+              done = true;
+            },
+            [&done](nsresult aRejectValue) {
+              ASSERT_TRUE(false);
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+// Test ShutdownStorage when a storage shutdown is already ongoing and storage
+// initialization is scheduled after that.
+TEST_F(TestQuotaManager, ShutdownStorage_OngoingWithScheduledInitialization) {
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(InitializeStorage());
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageInitialized());
+
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    nsTArray<RefPtr<BoolPromise>> promises;
+
+    promises.AppendElement(quotaManager->ShutdownStorage());
+    promises.AppendElement(quotaManager->InitializeStorage());
+    promises.AppendElement(quotaManager->ShutdownStorage());
+
+    bool done = false;
+
+    BoolPromise::All(GetCurrentSerialEventTarget(), promises)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](const CopyableTArray<bool>& aResolveValues) {
+              QuotaManager* quotaManager = QuotaManager::Get();
+              ASSERT_TRUE(quotaManager);
+
+              ASSERT_FALSE(quotaManager->IsStorageInitialized());
+
+              done = true;
+            },
+            [&done](nsresult aRejectValue) {
+              ASSERT_TRUE(false);
+
+              done = true;
+            });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+
+  ASSERT_NO_FATAL_FAILURE(AssertStorageNotInitialized());
+
+  ASSERT_NO_FATAL_FAILURE(ShutdownStorage());
+}
+
+// Test ShutdownStorage when a storage shutdown is already ongoing and a shared
+// client directory lock is requested after that.
+// The shared client directory lock doesn't have to be explicitly released
+// because it gets invalidated while it's still pending which causes that any
+// directory locks that were blocked by the shared client directory lock become
+// unblocked.
+TEST_F(TestQuotaManager, ShutdownStorage_OngoingWithClientDirectoryLock) {
+  PerformOnBackgroundThread([]() {
+    QuotaManager* quotaManager = QuotaManager::Get();
+    ASSERT_TRUE(quotaManager);
+
+    RefPtr<ClientDirectoryLock> directoryLock =
+        quotaManager->CreateDirectoryLock(GetTestClientMetadata(),
+                                          /* aExclusive */ false);
+
+    nsTArray<RefPtr<BoolPromise>> promises;
+
+    // This creates an exclusive directory lock internally.
+    promises.AppendElement(quotaManager->ShutdownStorage());
+
+    // This directory lock can't be acquired yet because a storage shutdown
+    // (which uses an exclusive diretory lock internall) is ongoing.
+    promises.AppendElement(directoryLock->Acquire());
+
+    // This second ShutdownStorage invalidates the directoryLock, so that
+    // directory lock can't ever be successfully acquired, the promise for it
+    // will be rejected when the first ShutdownStorage is finished (it releases
+    // its exclusive directory lock);
+    promises.AppendElement(quotaManager->ShutdownStorage());
+
+    bool done = false;
+
+    BoolPromise::AllSettled(GetCurrentSerialEventTarget(), promises)
+        ->Then(
+            GetCurrentSerialEventTarget(), __func__,
+            [&done](
+                const BoolPromise::AllSettledPromiseType::ResolveOrRejectValue&
+                    aValues) { done = true; });
+
+    SpinEventLoopUntil("Promise is fulfilled"_ns, [&done]() { return done; });
+  });
+}
+
+}  // namespace mozilla::dom::quota::test
diff --git a/dom/quota/test/gtest/TestResultExtensions.cpp b/dom/quota/test/gtest/TestResultExtensions.cpp
new file mode 100644
index 0000000000..137acc1423
--- /dev/null
+++ b/dom/quota/test/gtest/TestResultExtensions.cpp
@@ -0,0 +1,333 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "Common.h"
+#include "gtest/gtest.h"
+#include "mozilla/dom/QMResult.h"
+#include "mozilla/dom/quota/ResultExtensions.h"
+
+using namespace mozilla;
+using namespace mozilla::dom::quota;
+
+namespace {
+class TestClass {
+ public:
+  static constexpr int kTestValue = 42;
+
+  nsresult NonOverloadedNoInputComplex(std::pair<int, int>* aOut) {
+    *aOut = std::pair{kTestValue, kTestValue};
+    return NS_OK;
+  }
+  nsresult NonOverloadedNoInputFailsComplex(std::pair<int, int>* aOut) {
+    return NS_ERROR_FAILURE;
+  }
+};
+}  // namespace
+
+class DOM_Quota_ResultExtensions_ToResult : public DOM_Quota_Test {};
+class DOM_Quota_ResultExtensions_GenericErrorResult : public DOM_Quota_Test {};
+
+TEST_F(DOM_Quota_ResultExtensions_ToResult, FromBool) {
+  // success
+  {
+    auto res = ToResult(true);
+    static_assert(std::is_same_v<decltype(res), Result<Ok, nsresult>>);
+    EXPECT_TRUE(res.isOk());
+  }
+
+  // failure
+  {
+    auto res = ToResult(false);
+    static_assert(std::is_same_v<decltype(res), Result<Ok, nsresult>>);
+    EXPECT_TRUE(res.isErr());
+    EXPECT_EQ(res.unwrapErr(), NS_ERROR_FAILURE);
+  }
+}
+
+TEST_F(DOM_Quota_ResultExtensions_ToResult, FromQMResult_Failure) {
+  // copy
+  {
+    const auto res = ToQMResult(NS_ERROR_FAILURE);
+    auto okOrErr = ToResult<QMResult>(res);
+    static_assert(std::is_same_v<decltype(okOrErr), OkOrErr>);
+    ASSERT_TRUE(okOrErr.isErr());
+    auto err = okOrErr.unwrapErr();
+
+#ifdef QM_ERROR_STACKS_ENABLED
+    IncreaseExpectedStackId();
+
+    ASSERT_EQ(err.StackId(), ExpectedStackId());
+    ASSERT_EQ(err.FrameId(), 1u);
+    ASSERT_EQ(err.NSResult(), NS_ERROR_FAILURE);
+#else
+    ASSERT_EQ(err, NS_ERROR_FAILURE);
+#endif
+  }
+
+  // move
+  {
+    auto res = ToQMResult(NS_ERROR_FAILURE);
+    auto okOrErr = ToResult<QMResult>(std::move(res));
+    static_assert(std::is_same_v<decltype(okOrErr), OkOrErr>);
+    ASSERT_TRUE(okOrErr.isErr());
+    auto err = okOrErr.unwrapErr();
+
+#ifdef QM_ERROR_STACKS_ENABLED
+    IncreaseExpectedStackId();
+
+    ASSERT_EQ(err.StackId(), ExpectedStackId());
+    ASSERT_EQ(err.FrameId(), 1u);
+    ASSERT_EQ(err.NSResult(), NS_ERROR_FAILURE);
+#else
+    ASSERT_EQ(err, NS_ERROR_FAILURE);
+#endif
+  }
+}
+
+TEST_F(DOM_Quota_ResultExtensions_ToResult, FromNSResult_Failure_Macro) {
+  auto okOrErr = QM_TO_RESULT(NS_ERROR_FAILURE);
+  static_assert(std::is_same_v<decltype(okOrErr), OkOrErr>);
+  ASSERT_TRUE(okOrErr.isErr());
+  auto err = okOrErr.unwrapErr();
+
+#ifdef QM_ERROR_STACKS_ENABLED
+  IncreaseExpectedStackId();
+
+  ASSERT_EQ(err.StackId(), ExpectedStackId());
+  ASSERT_EQ(err.FrameId(), 1u);
+  ASSERT_EQ(err.NSResult(), NS_ERROR_FAILURE);
+#else
+  ASSERT_EQ(err, NS_ERROR_FAILURE);
+#endif
+}
+
+TEST_F(DOM_Quota_ResultExtensions_GenericErrorResult, ErrorPropagation) {
+  OkOrErr okOrErr1 = ToResult<QMResult>(ToQMResult(NS_ERROR_FAILURE));
+  const auto& err1 = okOrErr1.inspectErr();
+
+#ifdef QM_ERROR_STACKS_ENABLED
+  IncreaseExpectedStackId();
+
+  ASSERT_EQ(err1.StackId(), ExpectedStackId());
+  ASSERT_EQ(err1.FrameId(), 1u);
+  ASSERT_EQ(err1.NSResult(), NS_ERROR_FAILURE);
+#else
+  ASSERT_EQ(err1, NS_ERROR_FAILURE);
+#endif
+
+  OkOrErr okOrErr2 = okOrErr1.propagateErr();
+  const auto& err2 = okOrErr2.inspectErr();
+
+#ifdef QM_ERROR_STACKS_ENABLED
+  ASSERT_EQ(err2.StackId(), ExpectedStackId());
+  ASSERT_EQ(err2.FrameId(), 2u);
+  ASSERT_EQ(err2.NSResult(), NS_ERROR_FAILURE);
+#else
+  ASSERT_EQ(err2, NS_ERROR_FAILURE);
+#endif
+
+  OkOrErr okOrErr3 = okOrErr2.propagateErr();
+  const auto& err3 = okOrErr3.inspectErr();
+
+#ifdef QM_ERROR_STACKS_ENABLED
+  ASSERT_EQ(err3.StackId(), ExpectedStackId());
+  ASSERT_EQ(err3.FrameId(), 3u);
+  ASSERT_EQ(err3.NSResult(), NS_ERROR_FAILURE);
+#else
+  ASSERT_EQ(err3, NS_ERROR_FAILURE);
+#endif
+}
+
+TEST(DOM_Quota_ResultExtensions_ToResultGet, Lambda_NoInput)
+{
+  auto res = ToResultGet<int32_t>([](nsresult* aRv) -> int32_t {
+    *aRv = NS_OK;
+    return 42;
+  });
+
+  static_assert(std::is_same_v<decltype(res), Result<int32_t, nsresult>>);
+
+  EXPECT_TRUE(res.isOk());
+  EXPECT_EQ(res.unwrap(), 42);
+}
+
+TEST(DOM_Quota_ResultExtensions_ToResultGet, Lambda_NoInput_Err)
+{
+  auto res = ToResultGet<int32_t>([](nsresult* aRv) -> int32_t {
+    *aRv = NS_ERROR_FAILURE;
+    return -1;
+  });
+
+  static_assert(std::is_same_v<decltype(res), Result<int32_t, nsresult>>);
+
+  EXPECT_TRUE(res.isErr());
+  EXPECT_EQ(res.unwrapErr(), NS_ERROR_FAILURE);
+}
+
+TEST(DOM_Quota_ResultExtensions_ToResultGet, Lambda_WithInput)
+{
+  auto res = ToResultGet<int32_t>(
+      [](int32_t aValue, nsresult* aRv) -> int32_t {
+        *aRv = NS_OK;
+        return aValue * 2;
+      },
+      42);
+
+  static_assert(std::is_same_v<decltype(res), Result<int32_t, nsresult>>);
+
+  EXPECT_TRUE(res.isOk());
+  EXPECT_EQ(res.unwrap(), 84);
+}
+
+TEST(DOM_Quota_ResultExtensions_ToResultGet, Lambda_WithInput_Err)
+{
+  auto res = ToResultGet<int32_t>(
+      [](int32_t aValue, nsresult* aRv) -> int32_t {
+        *aRv = NS_ERROR_FAILURE;
+        return -1;
+      },
+      42);
+
+  static_assert(std::is_same_v<decltype(res), Result<int32_t, nsresult>>);
+
+  EXPECT_TRUE(res.isErr());
+  EXPECT_EQ(res.unwrapErr(), NS_ERROR_FAILURE);
+}
+
+TEST(DOM_Quota_ResultExtensions_ToResultGet, Lambda_NoInput_Macro_Typed)
+{
+  auto res = MOZ_TO_RESULT_GET_TYPED(int32_t, [](nsresult* aRv) -> int32_t {
+    *aRv = NS_OK;
+    return 42;
+  });
+
+  static_assert(std::is_same_v<decltype(res), Result<int32_t, nsresult>>);
+
+  EXPECT_TRUE(res.isOk());
+  EXPECT_EQ(res.unwrap(), 42);
+}
+
+TEST(DOM_Quota_ResultExtensions_ToResultGet, Lambda_NoInput_Macro_Typed_Parens)
+{
+  auto res =
+      MOZ_TO_RESULT_GET_TYPED((std::pair<int32_t, int32_t>),
+                              [](nsresult* aRv) -> std::pair<int32_t, int32_t> {
+                                *aRv = NS_OK;
+                                return std::pair{42, 42};
+                              });
+
+  static_assert(std::is_same_v<decltype(res),
+                               Result<std::pair<int32_t, int32_t>, nsresult>>);
+
+  EXPECT_TRUE(res.isOk());
+  EXPECT_EQ(res.unwrap(), (std::pair{42, 42}));
+}
+
+TEST(DOM_Quota_ResultExtensions_ToResultGet, Lambda_NoInput_Err_Macro_Typed)
+{
+  auto res = MOZ_TO_RESULT_GET_TYPED(int32_t, [](nsresult* aRv) -> int32_t {
+    *aRv = NS_ERROR_FAILURE;
+    return -1;
+  });
+
+  static_assert(std::is_same_v<decltype(res), Result<int32_t, nsresult>>);
+
+  EXPECT_TRUE(res.isErr());
+  EXPECT_EQ(res.unwrapErr(), NS_ERROR_FAILURE);
+}
+
+TEST(DOM_Quota_ResultExtensions_ToResultGet, Lambda_WithInput_Macro_Typed)
+{
+  auto res = MOZ_TO_RESULT_GET_TYPED(
+      int32_t,
+      [](int32_t aValue, nsresult* aRv) -> int32_t {
+        *aRv = NS_OK;
+        return aValue * 2;
+      },
+      42);
+
+  static_assert(std::is_same_v<decltype(res), Result<int32_t, nsresult>>);
+
+  EXPECT_TRUE(res.isOk());
+  EXPECT_EQ(res.unwrap(), 84);
+}
+
+TEST(DOM_Quota_ResultExtensions_ToResultGet, Lambda_WithInput_Err_Macro_Typed)
+{
+  auto res = MOZ_TO_RESULT_GET_TYPED(
+      int32_t,
+      [](int32_t aValue, nsresult* aRv) -> int32_t {
+        *aRv = NS_ERROR_FAILURE;
+        return -1;
+      },
+      42);
+
+  static_assert(std::is_same_v<decltype(res), Result<int32_t, nsresult>>);
+
+  EXPECT_TRUE(res.isErr());
+  EXPECT_EQ(res.unwrapErr(), NS_ERROR_FAILURE);
+}
+
+TEST(DOM_Quota_ResultExtensions_ToResultInvoke, Lambda_NoInput_Complex)
+{
+  TestClass foo;
+
+  // success
+  {
+    auto valOrErr =
+        ToResultInvoke<std::pair<int, int>>([&foo](std::pair<int, int>* out) {
+          return foo.NonOverloadedNoInputComplex(out);
+        });
+    static_assert(std::is_same_v<decltype(valOrErr),
+                                 Result<std::pair<int, int>, nsresult>>);
+    ASSERT_TRUE(valOrErr.isOk());
+    ASSERT_EQ((std::pair{TestClass::kTestValue, TestClass::kTestValue}),
+              valOrErr.unwrap());
+  }
+
+  // failure
+  {
+    auto valOrErr =
+        ToResultInvoke<std::pair<int, int>>([&foo](std::pair<int, int>* out) {
+          return foo.NonOverloadedNoInputFailsComplex(out);
+        });
+    static_assert(std::is_same_v<decltype(valOrErr),
+                                 Result<std::pair<int, int>, nsresult>>);
+    ASSERT_TRUE(valOrErr.isErr());
+    ASSERT_EQ(NS_ERROR_FAILURE, valOrErr.unwrapErr());
+  }
+}
+
+TEST(DOM_Quota_ResultExtensions_ToResultInvoke,
+     Lambda_NoInput_Complex_Macro_Typed)
+{
+  TestClass foo;
+
+  // success
+  {
+    auto valOrErr = MOZ_TO_RESULT_INVOKE_TYPED(
+        (std::pair<int, int>), [&foo](std::pair<int, int>* out) {
+          return foo.NonOverloadedNoInputComplex(out);
+        });
+    static_assert(std::is_same_v<decltype(valOrErr),
+                                 Result<std::pair<int, int>, nsresult>>);
+    ASSERT_TRUE(valOrErr.isOk());
+    ASSERT_EQ((std::pair{TestClass::kTestValue, TestClass::kTestValue}),
+              valOrErr.unwrap());
+  }
+
+  // failure
+  {
+    auto valOrErr = MOZ_TO_RESULT_INVOKE_TYPED(
+        (std::pair<int, int>), [&foo](std::pair<int, int>* out) {
+          return foo.NonOverloadedNoInputFailsComplex(out);
+        });
+    static_assert(std::is_same_v<decltype(valOrErr),
+                                 Result<std::pair<int, int>, nsresult>>);
+    ASSERT_TRUE(valOrErr.isErr());
+    ASSERT_EQ(NS_ERROR_FAILURE, valOrErr.unwrapErr());
+  }
+}
diff --git a/dom/quota/test/gtest/TestScopedLogExtraInfo.cpp b/dom/quota/test/gtest/TestScopedLogExtraInfo.cpp
new file mode 100644
index 0000000000..00a3393844
--- /dev/null
+++ b/dom/quota/test/gtest/TestScopedLogExtraInfo.cpp
@@ -0,0 +1,65 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/quota/ScopedLogExtraInfo.h"
+
+#include "gtest/gtest.h"
+
+using namespace mozilla::dom::quota;
+
+TEST(DOM_Quota_ScopedLogExtraInfo, AddAndRemove)
+{
+  static constexpr auto text = "foo"_ns;
+
+  {
+    const auto extraInfo =
+        ScopedLogExtraInfo{ScopedLogExtraInfo::kTagQuery, text};
+
+#ifdef QM_SCOPED_LOG_EXTRA_INFO_ENABLED
+    const auto& extraInfoMap = ScopedLogExtraInfo::GetExtraInfoMap();
+
+    EXPECT_EQ(text, *extraInfoMap.at(ScopedLogExtraInfo::kTagQuery));
+#endif
+  }
+
+#ifdef QM_SCOPED_LOG_EXTRA_INFO_ENABLED
+  const auto& extraInfoMap = ScopedLogExtraInfo::GetExtraInfoMap();
+
+  EXPECT_EQ(0u, extraInfoMap.count(ScopedLogExtraInfo::kTagQuery));
+#endif
+}
+
+TEST(DOM_Quota_ScopedLogExtraInfo, Nested)
+{
+  static constexpr auto text = "foo"_ns;
+  static constexpr auto nestedText = "bar"_ns;
+
+  {
+    const auto extraInfo =
+        ScopedLogExtraInfo{ScopedLogExtraInfo::kTagQuery, text};
+
+    {
+      const auto extraInfo =
+          ScopedLogExtraInfo{ScopedLogExtraInfo::kTagQuery, nestedText};
+
+#ifdef QM_SCOPED_LOG_EXTRA_INFO_ENABLED
+      const auto& extraInfoMap = ScopedLogExtraInfo::GetExtraInfoMap();
+      EXPECT_EQ(nestedText, *extraInfoMap.at(ScopedLogExtraInfo::kTagQuery));
+#endif
+    }
+
+#ifdef QM_SCOPED_LOG_EXTRA_INFO_ENABLED
+    const auto& extraInfoMap = ScopedLogExtraInfo::GetExtraInfoMap();
+    EXPECT_EQ(text, *extraInfoMap.at(ScopedLogExtraInfo::kTagQuery));
+#endif
+  }
+
+#ifdef QM_SCOPED_LOG_EXTRA_INFO_ENABLED
+  const auto& extraInfoMap = ScopedLogExtraInfo::GetExtraInfoMap();
+
+  EXPECT_EQ(0u, extraInfoMap.count(ScopedLogExtraInfo::kTagQuery));
+#endif
+}
diff --git a/dom/quota/test/gtest/TestStorageConnection.cpp b/dom/quota/test/gtest/TestStorageConnection.cpp
new file mode 100644
index 0000000000..9ff19ec44f
--- /dev/null
+++ b/dom/quota/test/gtest/TestStorageConnection.cpp
@@ -0,0 +1,283 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "QuotaManagerDependencyFixture.h"
+#include "mozIStorageConnection.h"
+#include "mozIStorageService.h"
+#include "mozStorageCID.h"
+#include "mozilla/dom/quota/IPCStreamCipherStrategy.h"
+#include "mozilla/dom/quota/QuotaCommon.h"
+#include "mozilla/dom/quota/QuotaManager.h"
+#include "mozilla/dom/quota/QuotaObject.h"
+#include "mozilla/dom/quota/ResultExtensions.h"
+#include "nsIFile.h"
+#include "nsIFileProtocolHandler.h"
+#include "nsIFileURL.h"
+#include "nsIURIMutator.h"
+#include "nss.h"
+
+namespace mozilla {
+
+struct NSSInitContextDeleter {
+  void operator()(NSSInitContext* p) { NSS_ShutdownContext(p); }
+};
+
+namespace dom::quota::test {
+
+namespace {
+
+void InitializeClientDirectory(const ClientMetadata& aClientMetadata) {
+  QuotaManager* quotaManager = QuotaManager::Get();
+
+  QM_TRY(MOZ_TO_RESULT(
+             quotaManager->EnsureTemporaryStorageIsInitializedInternal()),
+         QM_TEST_FAIL);
+
+  QM_TRY_INSPECT(const auto& directory,
+                 quotaManager
+                     ->EnsureTemporaryOriginIsInitialized(
+                         aClientMetadata.mPersistenceType, aClientMetadata)
+                     .map([](const auto& aPair) { return aPair.first; }),
+                 QM_TEST_FAIL);
+
+  QM_TRY(MOZ_TO_RESULT(directory->Append(
+             Client::TypeToString(aClientMetadata.mClientType))),
+         QM_TEST_FAIL);
+
+  QM_TRY_INSPECT(const bool& exists,
+                 MOZ_TO_RESULT_INVOKE_MEMBER(directory, Exists), QM_TEST_FAIL);
+
+  if (!exists) {
+    QM_TRY(MOZ_TO_RESULT(directory->Create(nsIFile::DIRECTORY_TYPE, 0755)),
+           QM_TEST_FAIL);
+  }
+}
+
+void CreateStorageConnection(
+    const ClientMetadata& aClientMetadata,
+    const Maybe<int64_t>& aMaybeDirectoryLockId,
+    const Maybe<IPCStreamCipherStrategy::KeyType>& aMaybeKey,
+    nsCOMPtr<mozIStorageConnection>& aConnection) {
+  QuotaManager* quotaManager = QuotaManager::Get();
+
+  QM_TRY_UNWRAP(auto databaseFile,
+                quotaManager->GetOriginDirectory(aClientMetadata),
+                QM_TEST_FAIL);
+
+  QM_TRY(MOZ_TO_RESULT(databaseFile->Append(
+             Client::TypeToString(aClientMetadata.mClientType))),
+         QM_TEST_FAIL);
+
+  QM_TRY(MOZ_TO_RESULT(databaseFile->Append(u"testdatabase.sqlite"_ns)),
+         QM_TEST_FAIL);
+
+  QM_TRY_INSPECT(
+      const auto& protocolHandler,
+      MOZ_TO_RESULT_GET_TYPED(nsCOMPtr<nsIProtocolHandler>,
+                              MOZ_SELECT_OVERLOAD(do_GetService),
+                              NS_NETWORK_PROTOCOL_CONTRACTID_PREFIX "file"),
+      QM_TEST_FAIL);
+
+  QM_TRY_INSPECT(const auto& fileHandler,
+                 MOZ_TO_RESULT_GET_TYPED(nsCOMPtr<nsIFileProtocolHandler>,
+                                         MOZ_SELECT_OVERLOAD(do_QueryInterface),
+                                         protocolHandler),
+                 QM_TEST_FAIL);
+
+  QM_TRY_INSPECT(
+      const auto& mutator,
+      MOZ_TO_RESULT_INVOKE_MEMBER_TYPED(nsCOMPtr<nsIURIMutator>, fileHandler,
+                                        NewFileURIMutator, databaseFile),
+      QM_TEST_FAIL);
+
+  const auto directoryLockIdClause = [&aMaybeDirectoryLockId] {
+    nsAutoCString directoryLockIdClause;
+    if (aMaybeDirectoryLockId) {
+      directoryLockIdClause =
+          "&directoryLockId="_ns + IntToCString(*aMaybeDirectoryLockId);
+    }
+    return directoryLockIdClause;
+  }();
+
+  const auto keyClause = [&aMaybeKey] {
+    nsAutoCString keyClause;
+    if (aMaybeKey) {
+      keyClause.AssignLiteral("&key=");
+      for (uint8_t byte : IPCStreamCipherStrategy::SerializeKey(*aMaybeKey)) {
+        keyClause.AppendPrintf("%02x", byte);
+      }
+    }
+    return keyClause;
+  }();
+
+  QM_TRY_INSPECT(
+      const auto& fileURL,
+      ([&mutator, &directoryLockIdClause,
+        &keyClause]() -> Result<nsCOMPtr<nsIFileURL>, nsresult> {
+        nsCOMPtr<nsIFileURL> result;
+        QM_TRY(MOZ_TO_RESULT(NS_MutateURI(mutator)
+                                 .SetQuery("cache=private"_ns +
+                                           directoryLockIdClause + keyClause)
+                                 .Finalize(result)));
+        return result;
+      }()),
+      QM_TEST_FAIL);
+
+  QM_TRY_INSPECT(const auto& storageService,
+                 MOZ_TO_RESULT_GET_TYPED(nsCOMPtr<mozIStorageService>,
+                                         MOZ_SELECT_OVERLOAD(do_GetService),
+                                         MOZ_STORAGE_SERVICE_CONTRACTID),
+                 QM_TEST_FAIL);
+
+  QM_TRY_UNWRAP(auto connection,
+                MOZ_TO_RESULT_INVOKE_MEMBER_TYPED(
+                    nsCOMPtr<mozIStorageConnection>, storageService,
+                    OpenDatabaseWithFileURL, fileURL, EmptyCString(),
+                    mozIStorageService::CONNECTION_DEFAULT),
+                QM_TEST_FAIL);
+
+  QM_TRY(MOZ_TO_RESULT(
+             connection->ExecuteSimpleSQL("PRAGMA journal_mode = wal;"_ns)),
+         QM_TEST_FAIL);
+
+  // The connection needs to be re-created, otherwise GetQuotaObjects is not
+  // able to get the quota object for the journal file.
+
+  QM_TRY(MOZ_TO_RESULT(connection->Close()), QM_TEST_FAIL);
+
+  QM_TRY_UNWRAP(connection,
+                MOZ_TO_RESULT_INVOKE_MEMBER_TYPED(
+                    nsCOMPtr<mozIStorageConnection>, storageService,
+                    OpenDatabaseWithFileURL, fileURL, EmptyCString(),
+                    mozIStorageService::CONNECTION_DEFAULT),
+                QM_TEST_FAIL);
+
+  aConnection = std::move(connection);
+}
+
+}  // namespace
+
+class TestStorageConnection : public QuotaManagerDependencyFixture {
+ public:
+  static void SetUpTestCase() {
+    // Do this only once, do not tear it down per test case.
+    if (!sNssContext) {
+      sNssContext.reset(
+          NSS_InitContext("", "", "", "", nullptr,
+                          NSS_INIT_READONLY | NSS_INIT_NOCERTDB |
+                              NSS_INIT_NOMODDB | NSS_INIT_FORCEOPEN |
+                              NSS_INIT_OPTIMIZESPACE | NSS_INIT_NOROOTINIT));
+    }
+
+    ASSERT_NO_FATAL_FAILURE(InitializeFixture());
+  }
+
+  static void TearDownTestCase() {
+    ASSERT_NO_FATAL_FAILURE(ShutdownFixture());
+
+    sNssContext = nullptr;
+  }
+
+  void TearDown() override {
+    ASSERT_NO_FATAL_FAILURE(ClearStoragesForOrigin(GetTestOriginMetadata()));
+  }
+
+ private:
+  struct NSSInitContextDeleter {
+    void operator()(NSSInitContext* p) { NSS_ShutdownContext(p); }
+  };
+  inline static std::unique_ptr<NSSInitContext, NSSInitContextDeleter>
+      sNssContext;
+};
+
+TEST_F(TestStorageConnection, BaseVFS) {
+  // XXX This call can't be wrapped with ASSERT_NO_FATAL_FAILURE because
+  // base-toolchains builds fail with: error: duplicate label
+  // 'gtest_label_testnofatal_214'
+  PerformClientDirectoryTest(GetTestClientMetadata(), [](int64_t) {
+    ASSERT_NO_FATAL_FAILURE(InitializeClientDirectory(GetTestClientMetadata()));
+
+    nsCOMPtr<mozIStorageConnection> connection;
+    ASSERT_NO_FATAL_FAILURE(CreateStorageConnection(
+        GetTestClientMetadata(), Nothing(), Nothing(), connection));
+
+    RefPtr<QuotaObject> quotaObject;
+    RefPtr<QuotaObject> journalQuotaObject;
+
+    nsresult rv = connection->GetQuotaObjects(
+        getter_AddRefs(quotaObject), getter_AddRefs(journalQuotaObject));
+    ASSERT_EQ(rv, NS_ERROR_FAILURE);
+
+    ASSERT_FALSE(quotaObject);
+    ASSERT_FALSE(journalQuotaObject);
+
+    QM_TRY(MOZ_TO_RESULT(connection->Close()), QM_TEST_FAIL);
+  });
+}
+
+TEST_F(TestStorageConnection, QuotaVFS) {
+  // XXX This call can't be wrapped with ASSERT_NO_FATAL_FAILURE because
+  // base-toolchains builds fail with: error: duplicate label
+  // 'gtest_label_testnofatal_214'
+  PerformClientDirectoryTest(
+      GetTestClientMetadata(), [](int64_t aDirectoryLockId) {
+        ASSERT_NO_FATAL_FAILURE(
+            InitializeClientDirectory(GetTestClientMetadata()));
+
+        nsCOMPtr<mozIStorageConnection> connection;
+        ASSERT_NO_FATAL_FAILURE(CreateStorageConnection(GetTestClientMetadata(),
+                                                        Some(aDirectoryLockId),
+                                                        Nothing(), connection));
+
+        RefPtr<QuotaObject> quotaObject;
+        RefPtr<QuotaObject> journalQuotaObject;
+
+        QM_TRY(MOZ_TO_RESULT(connection->GetQuotaObjects(
+                   getter_AddRefs(quotaObject),
+                   getter_AddRefs(journalQuotaObject))),
+               QM_TEST_FAIL);
+
+        ASSERT_TRUE(quotaObject);
+        ASSERT_TRUE(journalQuotaObject);
+
+        QM_TRY(MOZ_TO_RESULT(connection->Close()), QM_TEST_FAIL);
+      });
+}
+
+TEST_F(TestStorageConnection, ObfuscatingVFS) {
+  // XXX This call can't be wrapped with ASSERT_NO_FATAL_FAILURE because
+  // base-toolchains builds fail with: error: duplicate label
+  // 'gtest_label_testnofatal_214'
+  PerformClientDirectoryTest(
+      GetTestClientMetadata(), [](int64_t aDirectoryLockId) {
+        ASSERT_NO_FATAL_FAILURE(
+            InitializeClientDirectory(GetTestClientMetadata()));
+
+        QM_TRY_INSPECT(const auto& key, IPCStreamCipherStrategy::GenerateKey(),
+                       QM_TEST_FAIL);
+
+        nsCOMPtr<mozIStorageConnection> connection;
+        ASSERT_NO_FATAL_FAILURE(CreateStorageConnection(GetTestClientMetadata(),
+                                                        Some(aDirectoryLockId),
+                                                        Some(key), connection));
+
+        RefPtr<QuotaObject> quotaObject;
+        RefPtr<QuotaObject> journalQuotaObject;
+
+        QM_TRY(MOZ_TO_RESULT(connection->GetQuotaObjects(
+                   getter_AddRefs(quotaObject),
+                   getter_AddRefs(journalQuotaObject))),
+               QM_TEST_FAIL);
+
+        ASSERT_TRUE(quotaObject);
+        ASSERT_TRUE(journalQuotaObject);
+
+        QM_TRY(MOZ_TO_RESULT(connection->Close()), QM_TEST_FAIL);
+      });
+}
+
+}  // namespace dom::quota::test
+}  // namespace mozilla
diff --git a/dom/quota/test/gtest/TestStorageOriginAttributes.cpp b/dom/quota/test/gtest/TestStorageOriginAttributes.cpp
new file mode 100644
index 0000000000..4529e1d53b
--- /dev/null
+++ b/dom/quota/test/gtest/TestStorageOriginAttributes.cpp
@@ -0,0 +1,165 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gtest/gtest.h"
+#include "mozilla/StorageOriginAttributes.h"
+
+namespace mozilla::dom::quota::test {
+
+TEST(DOM_Quota_StorageOriginAttributes, PopulateFromOrigin_NoOriginAttributes)
+{
+  {
+    StorageOriginAttributes originAttributes;
+    nsCString originNoSuffix;
+    bool ok = originAttributes.PopulateFromOrigin("https://www.example.com"_ns,
+                                                  originNoSuffix);
+
+    ASSERT_TRUE(ok);
+    ASSERT_FALSE(originAttributes.InIsolatedMozBrowser());
+    ASSERT_TRUE(originNoSuffix.Equals("https://www.example.com"_ns));
+  }
+}
+
+TEST(DOM_Quota_StorageOriginAttributes,
+     PopulateFromOrigin_InvalidOriginAttribute)
+{
+  {
+    StorageOriginAttributes originAttributes;
+    nsCString originNoSuffix;
+    bool ok = originAttributes.PopulateFromOrigin(
+        "https://www.example.com^foo=bar"_ns, originNoSuffix);
+
+    ASSERT_FALSE(ok);
+    ASSERT_FALSE(originAttributes.InIsolatedMozBrowser());
+    ASSERT_TRUE(originNoSuffix.Equals("https://www.example.com"_ns));
+  }
+}
+
+TEST(DOM_Quota_StorageOriginAttributes,
+     PopulateFromOrigin_InIsolatedMozBrowser_Valid)
+{
+  {
+    StorageOriginAttributes originAttributes;
+    nsCString originNoSuffix;
+    bool ok = originAttributes.PopulateFromOrigin(
+        "https://www.example.com^inBrowser=1"_ns, originNoSuffix);
+
+    ASSERT_TRUE(ok);
+    ASSERT_TRUE(originAttributes.InIsolatedMozBrowser());
+    ASSERT_TRUE(originNoSuffix.Equals("https://www.example.com"_ns));
+  }
+}
+
+TEST(DOM_Quota_StorageOriginAttributes,
+     PopulateFromOrigin_InIsolatedMozBrowser_Invalid)
+{
+  {
+    StorageOriginAttributes originAttributes;
+    nsCString originNoSuffix;
+    bool ok = originAttributes.PopulateFromOrigin(
+        "https://www.example.com^inBrowser=0"_ns, originNoSuffix);
+
+    ASSERT_FALSE(ok);
+    ASSERT_FALSE(originAttributes.InIsolatedMozBrowser());
+    ASSERT_TRUE(originNoSuffix.Equals("https://www.example.com"_ns));
+  }
+
+  {
+    StorageOriginAttributes originAttributes;
+    nsCString originNoSuffix;
+    bool ok = originAttributes.PopulateFromOrigin(
+        "https://www.example.com^inBrowser=true"_ns, originNoSuffix);
+
+    ASSERT_FALSE(ok);
+    ASSERT_FALSE(originAttributes.InIsolatedMozBrowser());
+    ASSERT_TRUE(originNoSuffix.Equals("https://www.example.com"_ns));
+  }
+
+  {
+    StorageOriginAttributes originAttributes;
+    nsCString originNoSuffix;
+    bool ok = originAttributes.PopulateFromOrigin(
+        "https://www.example.com^inBrowser=false"_ns, originNoSuffix);
+
+    ASSERT_FALSE(ok);
+    ASSERT_FALSE(originAttributes.InIsolatedMozBrowser());
+    ASSERT_TRUE(originNoSuffix.Equals("https://www.example.com"_ns));
+  }
+}
+
+TEST(DOM_Quota_StorageOriginAttributes, PopulateFromOrigin_UserContextId_Valid)
+{
+  {
+    StorageOriginAttributes originAttributes;
+    nsCString originNoSuffix;
+    bool ok = originAttributes.PopulateFromOrigin(
+        "https://www.example.com^userContextId=1"_ns, originNoSuffix);
+
+    ASSERT_TRUE(ok);
+    ASSERT_EQ(originAttributes.UserContextId(), 1u);
+    ASSERT_TRUE(originNoSuffix.Equals("https://www.example.com"_ns));
+  }
+
+  {
+    StorageOriginAttributes originAttributes;
+    nsCString originNoSuffix;
+    bool ok = originAttributes.PopulateFromOrigin(
+        "https://www.example.com^userContextId=42"_ns, originNoSuffix);
+
+    ASSERT_TRUE(ok);
+    ASSERT_EQ(originAttributes.UserContextId(), 42u);
+    ASSERT_TRUE(originNoSuffix.Equals("https://www.example.com"_ns));
+  }
+}
+
+TEST(DOM_Quota_StorageOriginAttributes,
+     PopulateFromOrigin_UserContextId_Invalid)
+{
+  {
+    StorageOriginAttributes originAttributes;
+    nsCString originNoSuffix;
+    bool ok = originAttributes.PopulateFromOrigin(
+        "https://www.example.com^userContextId=foo"_ns, originNoSuffix);
+
+    ASSERT_FALSE(ok);
+    ASSERT_EQ(originAttributes.UserContextId(), 0u);
+    ASSERT_TRUE(originNoSuffix.Equals("https://www.example.com"_ns));
+  }
+}
+
+TEST(DOM_Quota_StorageOriginAttributes, PopulateFromOrigin_Mixed_Valid)
+{
+  {
+    StorageOriginAttributes originAttributes;
+    nsCString originNoSuffix;
+    bool ok = originAttributes.PopulateFromOrigin(
+        "https://www.example.com^inBrowser=1&userContextId=1"_ns,
+        originNoSuffix);
+
+    ASSERT_TRUE(ok);
+    ASSERT_TRUE(originAttributes.InIsolatedMozBrowser());
+    ASSERT_EQ(originAttributes.UserContextId(), 1u);
+    ASSERT_TRUE(originNoSuffix.Equals("https://www.example.com"_ns));
+  }
+}
+
+TEST(DOM_Quota_StorageOriginAttributes, PopulateFromOrigin_Mixed_Invalid)
+{
+  {
+    StorageOriginAttributes originAttributes;
+    nsCString originNoSuffix;
+    bool ok = originAttributes.PopulateFromOrigin(
+        "https://www.example.com^inBrowser=1&userContextId=1&foo=bar"_ns,
+        originNoSuffix);
+
+    ASSERT_FALSE(ok);
+    ASSERT_TRUE(originAttributes.InIsolatedMozBrowser());
+    ASSERT_EQ(originAttributes.UserContextId(), 1u);
+    ASSERT_TRUE(originNoSuffix.Equals("https://www.example.com"_ns));
+  }
+}
+
+}  // namespace mozilla::dom::quota::test
diff --git a/dom/quota/test/gtest/TestStringifyUtils.cpp b/dom/quota/test/gtest/TestStringifyUtils.cpp
new file mode 100644
index 0000000000..5d50b31f14
--- /dev/null
+++ b/dom/quota/test/gtest/TestStringifyUtils.cpp
@@ -0,0 +1,60 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/quota/StringifyUtils.h"
+
+#include "gtest/gtest.h"
+
+namespace mozilla::dom::quota {
+
+class B;
+class A : public Stringifyable {
+ public:
+  A() : mB(nullptr) {}
+  virtual void DoStringify(nsACString& aData) override;
+  void setB(B* aB) { mB = aB; }
+
+ private:
+  B* mB;
+};
+
+class B : public Stringifyable {
+ public:
+  B() : mA(nullptr) {}
+  virtual void DoStringify(nsACString& aData) override;
+  void setA(A* aA) { mA = aA; }
+
+ private:
+  A* mA;
+};
+
+void A::DoStringify(nsACString& aData) {
+  aData.Append("Class A content."_ns);
+  mB->Stringify(aData);
+}
+
+void B::DoStringify(nsACString& aData) {
+  aData.Append("Class B content.");
+  mA->Stringify(aData);
+}
+
+TEST(DOM_Quota_StringifyUtils, Nested)
+{
+  A a1;
+  A a2;
+  B b;
+  a1.setB(&b);
+  b.setA(&a2);
+  a2.setB(&b);
+  nsCString msg;
+  a1.Stringify(msg);
+
+  EXPECT_EQ(
+      0, strcmp("{Class A content.{Class B content.{Class A content.(...)}}}",
+                msg.get()));
+}
+
+}  // namespace mozilla::dom::quota
diff --git a/dom/quota/test/gtest/TestTelemetry.cpp b/dom/quota/test/gtest/TestTelemetry.cpp
new file mode 100644
index 0000000000..7936a5a253
--- /dev/null
+++ b/dom/quota/test/gtest/TestTelemetry.cpp
@@ -0,0 +1,185 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/ScriptSettings.h"
+#include "mozilla/dom/SimpleGlobalObject.h"
+#include "mozilla/gtest/MozAssertions.h"
+#include "nsITelemetry.h"
+#include "QuotaManagerDependencyFixture.h"
+
+namespace mozilla::dom::quota::test {
+
+namespace {
+
+namespace js_helpers {
+
+void CallFunction(JSContext* aCx, JS::Handle<JS::Value> aValue,
+                  const char* aName, JS::MutableHandle<JS::Value> aResult) {
+  JS::Rooted<JSObject*> obj(aCx, &aValue.toObject());
+
+  JS::Rooted<JS::Value> result(aCx);
+  ASSERT_TRUE(JS_CallFunctionName(aCx, obj, aName,
+                                  JS::HandleValueArray::empty(), &result));
+
+  aResult.set(result);
+}
+
+void HasProperty(JSContext* aCx, JS::Handle<JS::Value> aValue,
+                 const char* aName, bool* aResult) {
+  JS::Rooted<JSObject*> obj(aCx, &aValue.toObject());
+
+  bool result;
+  ASSERT_TRUE(JS_HasProperty(aCx, obj, aName, &result));
+
+  *aResult = result;
+}
+
+void GetProperty(JSContext* aCx, JS::Handle<JS::Value> aValue,
+                 const char* aName, JS::MutableHandle<JS::Value> aResult) {
+  JS::Rooted<JSObject*> obj(aCx, &aValue.toObject());
+
+  JS::Rooted<JS::Value> result(aCx);
+  ASSERT_TRUE(JS_GetProperty(aCx, obj, aName, &result));
+
+  aResult.set(result);
+}
+
+void Enumerate(JSContext* aCx, JS::Handle<JS::Value> aValue,
+               JS::MutableHandle<JS::IdVector> aResult) {
+  JS::Rooted<JSObject*> obj(aCx, &aValue.toObject());
+  ASSERT_TRUE(JS_Enumerate(aCx, obj, aResult));
+}
+
+void GetElement(JSContext* aCx, JS::Handle<JS::Value> aValue, uint32_t aIndex,
+                JS::MutableHandle<JS::Value> aResult) {
+  JS::Rooted<JSObject*> obj(aCx, &aValue.toObject());
+
+  JS::Rooted<JS::Value> result(aCx);
+  ASSERT_TRUE(JS_GetElement(aCx, obj, aIndex, &result));
+
+  aResult.set(result);
+}
+
+void GetIndexValue(JSContext* aCx, JS::Handle<JS::Value> aValues,
+                   JS::PropertyKey aIndexId, uint32_t* aResult) {
+  nsAutoJSString indexId;
+  ASSERT_TRUE(indexId.init(aCx, aIndexId));
+
+  nsresult rv;
+  const auto index = indexId.ToInteger64(&rv);
+  ASSERT_NS_SUCCEEDED(rv);
+
+  JS::Rooted<JS::Value> element(aCx);
+  GetElement(aCx, aValues, index, &element);
+
+  uint32_t value = 0;
+  ASSERT_TRUE(JS::ToUint32(aCx, element, &value));
+
+  *aResult = value;
+}
+
+}  // namespace js_helpers
+
+}  // namespace
+
+TEST(DOM_Quota_Telemetry, ShutdownTime)
+{
+  nsCOMPtr<nsITelemetry> telemetry =
+      do_GetService("@mozilla.org/base/telemetry;1");
+
+  JSObject* simpleGlobal = dom::SimpleGlobalObject::Create(
+      dom::SimpleGlobalObject::GlobalType::BindingDetail);
+
+  JS::Rooted<JSObject*> global(dom::RootingCx(), simpleGlobal);
+
+  AutoJSAPI jsapi;
+  ASSERT_TRUE(jsapi.Init(global));
+
+  JSContext* cx = jsapi.cx();
+
+  JS::Rooted<JS::Value> histogram(cx);
+  ASSERT_NS_SUCCEEDED(telemetry->GetKeyedHistogramById("QM_SHUTDOWN_TIME_V0"_ns,
+                                                       cx, &histogram));
+
+  JS::Rooted<JS::Value> dummy(cx);
+  ASSERT_NO_FATAL_FAILURE(
+      js_helpers::CallFunction(cx, histogram, "clear", &dummy));
+
+  ASSERT_NO_FATAL_FAILURE(QuotaManagerDependencyFixture::InitializeFixture());
+  ASSERT_NO_FATAL_FAILURE(QuotaManagerDependencyFixture::ShutdownFixture());
+
+  JS::Rooted<JS::Value> snapshot(cx);
+  ASSERT_NO_FATAL_FAILURE(
+      js_helpers::CallFunction(cx, histogram, "snapshot", &snapshot));
+
+  {
+    bool hasKey = false;
+    ASSERT_NO_FATAL_FAILURE(
+        js_helpers::HasProperty(cx, snapshot, "Normal", &hasKey));
+    ASSERT_TRUE(hasKey);
+
+    JS::Rooted<JS::Value> key(cx);
+    ASSERT_NO_FATAL_FAILURE(
+        js_helpers::GetProperty(cx, snapshot, "Normal", &key));
+
+    JS::Rooted<JS::Value> values(cx);
+    ASSERT_NO_FATAL_FAILURE(
+        js_helpers::GetProperty(cx, key, "values", &values));
+
+    JS::Rooted<JS::IdVector> indexIds(cx, JS::IdVector(cx));
+    ASSERT_NO_FATAL_FAILURE(js_helpers::Enumerate(cx, values, &indexIds));
+    ASSERT_TRUE(indexIds.length() == 2u || indexIds.length() == 3u);
+
+    if (indexIds.length() == 2) {
+      uint32_t value = 0u;
+
+      ASSERT_NO_FATAL_FAILURE(
+          js_helpers::GetIndexValue(cx, values, indexIds[0], &value));
+      ASSERT_EQ(value, 1u);
+
+      ASSERT_NO_FATAL_FAILURE(
+          js_helpers::GetIndexValue(cx, values, indexIds[1], &value));
+      ASSERT_EQ(value, 0u);
+    } else {
+      uint32_t value = 1u;
+
+      ASSERT_NO_FATAL_FAILURE(
+          js_helpers::GetIndexValue(cx, values, indexIds[0], &value));
+      ASSERT_EQ(value, 0u);
+
+      ASSERT_NO_FATAL_FAILURE(
+          js_helpers::GetIndexValue(cx, values, indexIds[1], &value));
+      ASSERT_EQ(value, 1u);
+
+      ASSERT_NO_FATAL_FAILURE(
+          js_helpers::GetIndexValue(cx, values, indexIds[2], &value));
+      ASSERT_EQ(value, 0u);
+    }
+  }
+
+  {
+    bool hasKey = true;
+    ASSERT_NO_FATAL_FAILURE(
+        js_helpers::HasProperty(cx, snapshot, "WasSuspended", &hasKey));
+    ASSERT_FALSE(hasKey);
+  }
+
+  {
+    bool hasKey = true;
+    ASSERT_NO_FATAL_FAILURE(
+        js_helpers::HasProperty(cx, snapshot, "TimeStampErr1", &hasKey));
+    ASSERT_FALSE(hasKey);
+  }
+
+  {
+    bool hasKey = true;
+    ASSERT_NO_FATAL_FAILURE(
+        js_helpers::HasProperty(cx, snapshot, "TimeStampErr2", &hasKey));
+    ASSERT_FALSE(hasKey);
+  }
+}
+
+}  // namespace mozilla::dom::quota::test
diff --git a/dom/quota/test/gtest/TestUsageInfo.cpp b/dom/quota/test/gtest/TestUsageInfo.cpp
new file mode 100644
index 0000000000..124783b715
--- /dev/null
+++ b/dom/quota/test/gtest/TestUsageInfo.cpp
@@ -0,0 +1,136 @@
+/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set ts=8 sts=2 et sw=2 tw=80: */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "mozilla/dom/quota/UsageInfo.h"
+
+#include "gtest/gtest.h"
+
+#include <cstdint>
+#include <memory>
+#include <ostream>
+#include <utility>
+#include "mozilla/Maybe.h"
+#include "mozilla/dom/quota/QuotaCommon.h"
+#include "mozilla/fallible.h"
+
+using namespace mozilla;
+using namespace mozilla::dom::quota;
+
+namespace {
+constexpr uint64_t kTestValue = 42;
+constexpr uint64_t kTestValueZero = 0;
+}  // namespace
+
+TEST(DOM_Quota_UsageInfo, DefaultConstructed)
+{
+  const UsageInfo usageInfo;
+  EXPECT_EQ(Nothing(), usageInfo.FileUsage());
+  EXPECT_EQ(Nothing(), usageInfo.TotalUsage());
+}
+
+TEST(DOM_Quota_UsageInfo, FileOnly)
+{
+  const UsageInfo usageInfo = [] {
+    UsageInfo usageInfo;
+    usageInfo += FileUsageType(Some(kTestValue));
+    return usageInfo;
+  }();
+  EXPECT_EQ(Some(kTestValue), usageInfo.FileUsage());
+  EXPECT_EQ(Some(kTestValue), usageInfo.TotalUsage());
+}
+
+TEST(DOM_Quota_UsageInfo, DatabaseOnly)
+{
+  const UsageInfo usageInfo = [] {
+    UsageInfo usageInfo;
+    usageInfo += DatabaseUsageType(Some(kTestValue));
+    return usageInfo;
+  }();
+  EXPECT_EQ(Nothing(), usageInfo.FileUsage());
+  EXPECT_EQ(Some(kTestValue), usageInfo.TotalUsage());
+}
+
+TEST(DOM_Quota_UsageInfo, FileOnly_Zero)
+{
+  const UsageInfo usageInfo = [] {
+    UsageInfo usageInfo;
+    usageInfo += FileUsageType(Some(kTestValueZero));
+    return usageInfo;
+  }();
+  EXPECT_EQ(Some(kTestValueZero), usageInfo.FileUsage());
+  EXPECT_EQ(Some(kTestValueZero), usageInfo.TotalUsage());
+}
+
+TEST(DOM_Quota_UsageInfo, DatabaseOnly_Zero)
+{
+  const UsageInfo usageInfo = [] {
+    UsageInfo usageInfo;
+    usageInfo += DatabaseUsageType(Some(kTestValueZero));
+    return usageInfo;
+  }();
+  EXPECT_EQ(Nothing(), usageInfo.FileUsage());
+  EXPECT_EQ(Some(kTestValueZero), usageInfo.TotalUsage());
+}
+
+TEST(DOM_Quota_UsageInfo, Both)
+{
+  const UsageInfo usageInfo = [] {
+    UsageInfo usageInfo;
+    usageInfo += FileUsageType(Some(kTestValue));
+    usageInfo += DatabaseUsageType(Some(kTestValue));
+    return usageInfo;
+  }();
+  EXPECT_EQ(Some(kTestValue), usageInfo.FileUsage());
+  EXPECT_EQ(Some(2 * kTestValue), usageInfo.TotalUsage());
+}
+
+TEST(DOM_Quota_UsageInfo, Both_Zero)
+{
+  const UsageInfo usageInfo = [] {
+    UsageInfo usageInfo;
+    usageInfo += FileUsageType(Some(kTestValueZero));
+    usageInfo += DatabaseUsageType(Some(kTestValueZero));
+    return usageInfo;
+  }();
+  EXPECT_EQ(Some(kTestValueZero), usageInfo.FileUsage());
+  EXPECT_EQ(Some(kTestValueZero), usageInfo.TotalUsage());
+}
+
+TEST(DOM_Quota_UsageInfo, CapCombined)
+{
+  const UsageInfo usageInfo = [] {
+    UsageInfo usageInfo;
+    usageInfo += FileUsageType(Some(UINT64_MAX));
+    usageInfo += DatabaseUsageType(Some(kTestValue));
+    return usageInfo;
+  }();
+  EXPECT_EQ(Some(UINT64_MAX), usageInfo.FileUsage());
+  EXPECT_EQ(Some(UINT64_MAX), usageInfo.TotalUsage());
+}
+
+TEST(DOM_Quota_UsageInfo, CapFileUsage)
+{
+  const UsageInfo usageInfo = [] {
+    UsageInfo usageInfo;
+    usageInfo += FileUsageType(Some(UINT64_MAX));
+    usageInfo += FileUsageType(Some(kTestValue));
+    return usageInfo;
+  }();
+  EXPECT_EQ(Some(UINT64_MAX), usageInfo.FileUsage());
+  EXPECT_EQ(Some(UINT64_MAX), usageInfo.TotalUsage());
+}
+
+TEST(DOM_Quota_UsageInfo, CapDatabaseUsage)
+{
+  const UsageInfo usageInfo = [] {
+    UsageInfo usageInfo;
+    usageInfo += DatabaseUsageType(Some(UINT64_MAX));
+    usageInfo += DatabaseUsageType(Some(kTestValue));
+    return usageInfo;
+  }();
+  EXPECT_EQ(Nothing(), usageInfo.FileUsage());
+  EXPECT_EQ(Some(UINT64_MAX), usageInfo.TotalUsage());
+}
diff --git a/dom/quota/test/gtest/moz.build b/dom/quota/test/gtest/moz.build
new file mode 100644
index 0000000000..d983e3457e
--- /dev/null
+++ b/dom/quota/test/gtest/moz.build
@@ -0,0 +1,50 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, you can obtain one at http://mozilla.org/MPL/2.0/.
+
+EXPORTS.mozilla.dom.quota += [
+    "QuotaTestChild.h",
+    "QuotaTestParent.h",
+]
+
+EXPORTS.mozilla.dom.quota.test += [
+    "QuotaManagerDependencyFixture.h",
+]
+
+UNIFIED_SOURCES = [
+    "Common.cpp",
+    "QuotaManagerDependencyFixture.cpp",
+    "TestCheckedUnsafePtr.cpp",
+    "TestClientUsageArray.cpp",
+    "TestEncryptedStream.cpp",
+    "TestFileOutputStream.cpp",
+    "TestFlatten.cpp",
+    "TestForwardDecls.cpp",
+    "TestOriginParser.cpp",
+    "TestOriginScope.cpp",
+    "TestPersistenceType.cpp",
+    "TestQMResult.cpp",
+    "TestQuotaCommon.cpp",
+    "TestQuotaManager.cpp",
+    "TestResultExtensions.cpp",
+    "TestScopedLogExtraInfo.cpp",
+    "TestStorageConnection.cpp",
+    "TestStorageOriginAttributes.cpp",
+    "TestStringifyUtils.cpp",
+    "TestTelemetry.cpp",
+    "TestUsageInfo.cpp",
+]
+
+IPDL_SOURCES += [
+    "PQuotaTest.ipdl",
+]
+
+include("/ipc/chromium/chromium-config.mozbuild")
+
+FINAL_LIBRARY = "xul-gtest"
+
+LOCAL_INCLUDES += [
+    "/dom/quota",
+]