1 files changed, 56 insertions, 0 deletions
diff --git a/caps/tests/gtest/TestNullPrincipalPrecursor.cpp b/caps/tests/gtest/TestNullPrincipalPrecursor.cpp
new file mode 100644
index 0000000000..96db5aeffd
--- /dev/null
+++ b/caps/tests/gtest/TestNullPrincipalPrecursor.cpp
@@ -0,0 +1,56 @@
+/* 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/gtest/MozAssertions.h"
+#include "mozilla/NullPrincipal.h"
+#include "nsIURIMutator.h"
+#include "nsPrintfCString.h"
+
+namespace mozilla {
+
+TEST(NullPrincipalPrecursor, EscapingRoundTrips)
+{
+  nsTArray<nsCString> inputs;
+
+  inputs.AppendElements(mozilla::Span(std::array{
+      "mailbox:///dev/shm/tmp5wkt9ff_.mozrunner/Mail/Local%20Folders/secure-mail?number=5"_ns,
+  }));
+
+  // Add a string for every ASCII byte both escaped and unescaped.
+  for (uint8_t c = 0; c < 128; ++c) {
+    inputs.AppendElement(nsPrintfCString("%02X: %c", c, (char)c));
+    inputs.AppendElement(nsPrintfCString("%02X: %%%02X", c, c));
+  }
+
+  nsID dummyID{0xddf15eaf,
+               0x3837,
+               0x4678,
+               {0x80, 0x3b, 0x86, 0x86, 0xe8, 0x17, 0x66, 0x71}};
+  nsCOMPtr<nsIURI> baseURI = NullPrincipal::CreateURI(nullptr, &dummyID);
+  ASSERT_TRUE(baseURI);
+
+  for (auto& input : inputs) {
+    // First build an escaped version of the input string using
+    // `EscapePrecursorQuery`.
+    nsCString escaped(input);
+    NullPrincipal::EscapePrecursorQuery(escaped);
+
+    // Make sure that this escaped URI round-trips through a `moz-nullprincipal`
+    // URI's query without any additional escapes.
+    nsCOMPtr<nsIURI> clone;
+    EXPECT_NS_SUCCEEDED(
+        NS_MutateURI(baseURI).SetQuery(escaped).Finalize(clone));
+    nsCString query;
+    EXPECT_NS_SUCCEEDED(clone->GetQuery(query));
+    EXPECT_EQ(escaped, query);
+
+    // Try to unescape our escaped URI and make sure we recover the input
+    // string.
+    nsCString unescaped(escaped);
+    NullPrincipal::UnescapePrecursorQuery(unescaped);
+    EXPECT_EQ(input, unescaped);
+  }
+}
+
+}  // namespace mozilla