Adding upstream version 124.0.1.upstream/124.0.1

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

45 files changed, 3748 insertions, 0 deletions

diff --git a/toolkit/profile/xpcshell/head.js b/toolkit/profile/xpcshell/head.js
new file mode 100644
index 0000000000..dc354f5b62
--- /dev/null
+++ b/toolkit/profile/xpcshell/head.js
@@ -0,0 +1,623 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+const { NetUtil } = ChromeUtils.importESModule(
+  "resource://gre/modules/NetUtil.sys.mjs"
+);
+const { FileUtils } = ChromeUtils.importESModule(
+  "resource://gre/modules/FileUtils.sys.mjs"
+);
+const { AppConstants } = ChromeUtils.importESModule(
+  "resource://gre/modules/AppConstants.sys.mjs"
+);
+const { TelemetryTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/TelemetryTestUtils.sys.mjs"
+);
+
+const NS_ERROR_START_PROFILE_MANAGER = 0x805800c9;
+
+const UPDATE_CHANNEL = AppConstants.MOZ_UPDATE_CHANNEL;
+
+let gProfD = do_get_profile();
+let gDataHome = gProfD.clone();
+gDataHome.append("data");
+gDataHome.createUnique(Ci.nsIFile.DIRECTORY_TYPE, 0o755);
+let gDataHomeLocal = gProfD.clone();
+gDataHomeLocal.append("local");
+gDataHomeLocal.createUnique(Ci.nsIFile.DIRECTORY_TYPE, 0o755);
+
+let xreDirProvider = Cc["@mozilla.org/xre/directory-provider;1"].getService(
+  Ci.nsIXREDirProvider
+);
+xreDirProvider.setUserDataDirectory(gDataHome, false);
+xreDirProvider.setUserDataDirectory(gDataHomeLocal, true);
+
+let gIsDefaultApp = false;
+
+const ShellService = {
+  register() {
+    let registrar = Components.manager.QueryInterface(Ci.nsIComponentRegistrar);
+
+    let factory = {
+      createInstance(iid) {
+        return ShellService.QueryInterface(iid);
+      },
+    };
+
+    registrar.registerFactory(
+      this.ID,
+      "ToolkitShellService",
+      this.CONTRACT,
+      factory
+    );
+  },
+
+  isDefaultApplication() {
+    return gIsDefaultApp;
+  },
+
+  QueryInterface: ChromeUtils.generateQI(["nsIToolkitShellService"]),
+  ID: Components.ID("{ce724e0c-ed70-41c9-ab31-1033b0b591be}"),
+  CONTRACT: "@mozilla.org/toolkit/shell-service;1",
+};
+
+ShellService.register();
+
+let gIsLegacy = false;
+
+function enableLegacyProfiles() {
+  Services.env.set("MOZ_LEGACY_PROFILES", "1");
+
+  gIsLegacy = true;
+}
+
+function getProfileService() {
+  return Cc["@mozilla.org/toolkit/profile-service;1"].getService(
+    Ci.nsIToolkitProfileService
+  );
+}
+
+let PROFILE_DEFAULT = "default";
+let DEDICATED_NAME = `default-${UPDATE_CHANNEL}`;
+if (AppConstants.MOZ_DEV_EDITION) {
+  DEDICATED_NAME = PROFILE_DEFAULT = "dev-edition-default";
+}
+
+// Shared data for backgroundtasks tests.
+const BACKGROUNDTASKS_PROFILE_DATA = (() => {
+  let hash = xreDirProvider.getInstallHash();
+  let profileData = {
+    options: {
+      startWithLastProfile: true,
+    },
+    profiles: [
+      {
+        name: "Profile1",
+        path: "Path1",
+        default: false,
+      },
+      {
+        name: "Profile3",
+        path: "Path3",
+        default: false,
+      },
+    ],
+    installs: {
+      [hash]: {
+        default: "Path1",
+      },
+    },
+    backgroundTasksProfiles: [
+      {
+        name: `MozillaBackgroundTask-${hash}-unrelated_task`,
+        path: `saltsalt.MozillaBackgroundTask-${hash}-unrelated_task`,
+      },
+    ],
+  };
+  return profileData;
+})();
+
+/**
+ * Creates a random profile path for use.
+ */
+function makeRandomProfileDir(name) {
+  let file = gDataHome.clone();
+  file.append(name);
+  file.createUnique(Ci.nsIFile.DIRECTORY_TYPE, 0o755);
+  return file;
+}
+
+/**
+ * A wrapper around nsIToolkitProfileService.selectStartupProfile to make it
+ * a bit nicer to use from JS.
+ */
+function selectStartupProfile(args = [], isResetting = false, legacyHash = "") {
+  let service = getProfileService();
+  let rootDir = {};
+  let localDir = {};
+  let profile = {};
+  let didCreate = service.selectStartupProfile(
+    ["xpcshell", ...args],
+    isResetting,
+    UPDATE_CHANNEL,
+    legacyHash,
+    rootDir,
+    localDir,
+    profile
+  );
+
+  if (profile.value) {
+    Assert.ok(
+      rootDir.value.equals(profile.value.rootDir),
+      "Should have matched the root dir."
+    );
+    Assert.ok(
+      localDir.value.equals(profile.value.localDir),
+      "Should have matched the local dir."
+    );
+    Assert.ok(
+      service.currentProfile === profile.value,
+      "Should have marked the profile as the current profile."
+    );
+  } else {
+    Assert.ok(!service.currentProfile, "Should be no current profile.");
+  }
+
+  return {
+    rootDir: rootDir.value,
+    localDir: localDir.value,
+    profile: profile.value,
+    didCreate,
+  };
+}
+
+function testStartsProfileManager(args = [], isResetting = false) {
+  try {
+    selectStartupProfile(args, isResetting);
+    Assert.ok(false, "Should have started the profile manager");
+    checkStartupReason();
+  } catch (e) {
+    Assert.equal(
+      e.result,
+      NS_ERROR_START_PROFILE_MANAGER,
+      "Should have started the profile manager"
+    );
+  }
+}
+
+function safeGet(ini, section, key) {
+  try {
+    return ini.getString(section, key);
+  } catch (e) {
+    return null;
+  }
+}
+
+/**
+ * Writes a compatibility.ini file that marks the give profile directory as last
+ * used by the given install path.
+ */
+function writeCompatibilityIni(
+  dir,
+  appDir = FileUtils.getDir("CurProcD", []),
+  greDir = FileUtils.getDir("GreD", [])
+) {
+  let target = dir.clone();
+  target.append("compatibility.ini");
+
+  let factory = Cc["@mozilla.org/xpcom/ini-parser-factory;1"].getService(
+    Ci.nsIINIParserFactory
+  );
+  let ini = factory.createINIParser().QueryInterface(Ci.nsIINIParserWriter);
+
+  // The profile service doesn't care about these so just use fixed values
+  ini.setString(
+    "Compatibility",
+    "LastVersion",
+    "64.0a1_20180919123806/20180919123806"
+  );
+  ini.setString("Compatibility", "LastOSABI", "Darwin_x86_64-gcc3");
+
+  ini.setString(
+    "Compatibility",
+    "LastPlatformDir",
+    greDir.persistentDescriptor
+  );
+  ini.setString("Compatibility", "LastAppDir", appDir.persistentDescriptor);
+
+  ini.writeFile(target);
+}
+
+/**
+ * Writes a profiles.ini based on the passed profile data.
+ * profileData should contain two properties, options and profiles.
+ * options contains a single property, startWithLastProfile.
+ * profiles is an array of profiles each containing name, path and default
+ * properties.
+ */
+function writeProfilesIni(profileData) {
+  let target = gDataHome.clone();
+  target.append("profiles.ini");
+
+  let factory = Cc["@mozilla.org/xpcom/ini-parser-factory;1"].getService(
+    Ci.nsIINIParserFactory
+  );
+  let ini = factory.createINIParser().QueryInterface(Ci.nsIINIParserWriter);
+
+  const {
+    options = {},
+    profiles = [],
+    installs = null,
+    backgroundTasksProfiles = null,
+  } = profileData;
+
+  let { startWithLastProfile = true } = options;
+  ini.setString(
+    "General",
+    "StartWithLastProfile",
+    startWithLastProfile ? "1" : "0"
+  );
+
+  for (let i = 0; i < profiles.length; i++) {
+    let profile = profiles[i];
+    let section = `Profile${i}`;
+
+    ini.setString(section, "Name", profile.name);
+    ini.setString(section, "IsRelative", 1);
+    ini.setString(section, "Path", profile.path);
+
+    if (profile.default) {
+      ini.setString(section, "Default", "1");
+    }
+  }
+
+  if (backgroundTasksProfiles) {
+    let section = "BackgroundTasksProfiles";
+    for (let backgroundTasksProfile of backgroundTasksProfiles) {
+      ini.setString(
+        section,
+        backgroundTasksProfile.name,
+        backgroundTasksProfile.path
+      );
+    }
+  }
+
+  if (installs) {
+    ini.setString("General", "Version", "2");
+
+    for (let hash of Object.keys(installs)) {
+      ini.setString(`Install${hash}`, "Default", installs[hash].default);
+      if ("locked" in installs[hash]) {
+        ini.setString(
+          `Install${hash}`,
+          "Locked",
+          installs[hash].locked ? "1" : "0"
+        );
+      }
+    }
+
+    writeInstallsIni({ installs });
+  } else {
+    writeInstallsIni(null);
+  }
+
+  ini.writeFile(target);
+}
+
+/**
+ * Reads the existing profiles.ini into the same structure as that accepted by
+ * writeProfilesIni above. The profiles property is sorted according to name
+ * because the order is irrelevant and it makes testing easier if we can make
+ * that assumption.
+ */
+function readProfilesIni() {
+  let target = gDataHome.clone();
+  target.append("profiles.ini");
+
+  let profileData = {
+    options: {
+      startWithLastProfile: true,
+    },
+    profiles: [],
+    installs: null,
+  };
+
+  if (!target.exists()) {
+    return profileData;
+  }
+
+  let factory = Cc["@mozilla.org/xpcom/ini-parser-factory;1"].getService(
+    Ci.nsIINIParserFactory
+  );
+  let ini = factory.createINIParser(target);
+
+  profileData.options.startWithLastProfile =
+    safeGet(ini, "General", "StartWithLastProfile") == "1";
+  if (safeGet(ini, "General", "Version") == "2") {
+    profileData.installs = {};
+  }
+
+  let sections = ini.getSections();
+  while (sections.hasMore()) {
+    let section = sections.getNext();
+
+    if (section == "General") {
+      continue;
+    }
+
+    if (section.startsWith("Profile")) {
+      let isRelative = safeGet(ini, section, "IsRelative");
+      if (isRelative === null) {
+        break;
+      }
+      Assert.equal(
+        isRelative,
+        "1",
+        "Paths should always be relative in these tests."
+      );
+
+      let profile = {
+        name: safeGet(ini, section, "Name"),
+        path: safeGet(ini, section, "Path"),
+      };
+
+      try {
+        profile.default = ini.getString(section, "Default") == "1";
+        Assert.ok(
+          profile.default,
+          "The Default value is only written when true."
+        );
+      } catch (e) {
+        profile.default = false;
+      }
+
+      profileData.profiles.push(profile);
+    }
+
+    if (section.startsWith("Install")) {
+      Assert.ok(
+        profileData.installs,
+        "Should only see an install section if the ini version was correct."
+      );
+
+      profileData.installs[section.substring(7)] = {
+        default: safeGet(ini, section, "Default"),
+      };
+
+      let locked = safeGet(ini, section, "Locked");
+      if (locked !== null) {
+        profileData.installs[section.substring(7)].locked = locked;
+      }
+    }
+
+    if (section == "BackgroundTasksProfiles") {
+      profileData.backgroundTasksProfiles = [];
+      let backgroundTasksProfiles = ini.getKeys(section);
+      while (backgroundTasksProfiles.hasMore()) {
+        let name = backgroundTasksProfiles.getNext();
+        let path = ini.getString(section, name);
+        profileData.backgroundTasksProfiles.push({ name, path });
+      }
+      profileData.backgroundTasksProfiles.sort((a, b) =>
+        a.name.localeCompare(b.name)
+      );
+    }
+  }
+
+  profileData.profiles.sort((a, b) => a.name.localeCompare(b.name));
+
+  return profileData;
+}
+
+/**
+ * Writes an installs.ini based on the supplied data. Should be an object with
+ * keys for every installation hash each mapping to an object. Each object
+ * should have a default property for the relative path to the profile.
+ */
+function writeInstallsIni(installData) {
+  let target = gDataHome.clone();
+  target.append("installs.ini");
+
+  if (!installData) {
+    try {
+      target.remove(false);
+    } catch (e) {}
+    return;
+  }
+
+  const { installs = {} } = installData;
+
+  let factory = Cc["@mozilla.org/xpcom/ini-parser-factory;1"].getService(
+    Ci.nsIINIParserFactory
+  );
+  let ini = factory.createINIParser(null).QueryInterface(Ci.nsIINIParserWriter);
+
+  for (let hash of Object.keys(installs)) {
+    ini.setString(hash, "Default", installs[hash].default);
+    if ("locked" in installs[hash]) {
+      ini.setString(hash, "Locked", installs[hash].locked ? "1" : "0");
+    }
+  }
+
+  ini.writeFile(target);
+}
+
+/**
+ * Reads installs.ini into a structure like that used in the above function.
+ */
+function readInstallsIni() {
+  let target = gDataHome.clone();
+  target.append("installs.ini");
+
+  let installData = {
+    installs: {},
+  };
+
+  if (!target.exists()) {
+    return installData;
+  }
+
+  let factory = Cc["@mozilla.org/xpcom/ini-parser-factory;1"].getService(
+    Ci.nsIINIParserFactory
+  );
+  let ini = factory.createINIParser(target);
+
+  let sections = ini.getSections();
+  while (sections.hasMore()) {
+    let hash = sections.getNext();
+    if (hash != "General") {
+      installData.installs[hash] = {
+        default: safeGet(ini, hash, "Default"),
+      };
+
+      let locked = safeGet(ini, hash, "Locked");
+      if (locked !== null) {
+        installData.installs[hash].locked = locked;
+      }
+    }
+  }
+
+  return installData;
+}
+
+/**
+ * Check that the backup data in installs.ini matches the install data in
+ * profiles.ini.
+ */
+function checkBackup(
+  profileData = readProfilesIni(),
+  installData = readInstallsIni()
+) {
+  if (!profileData.installs) {
+    // If the profiles db isn't of the right version we wouldn't expect the
+    // backup to be accurate.
+    return;
+  }
+
+  Assert.deepEqual(
+    profileData.installs,
+    installData.installs,
+    "Backup installs.ini should match installs in profiles.ini"
+  );
+}
+
+/**
+ * Checks that the profile service seems to have the right data in it compared
+ * to profile and install data structured as in the above functions.
+ */
+function checkProfileService(
+  profileData = readProfilesIni(),
+  verifyBackup = true
+) {
+  let service = getProfileService();
+
+  let expectedStartWithLast = true;
+  if ("options" in profileData) {
+    expectedStartWithLast = profileData.options.startWithLastProfile;
+  }
+
+  Assert.equal(
+    service.startWithLastProfile,
+    expectedStartWithLast,
+    "Start with last profile should match."
+  );
+
+  let serviceProfiles = Array.from(service.profiles);
+
+  Assert.equal(
+    serviceProfiles.length,
+    profileData.profiles.length,
+    "Should be the same number of profiles."
+  );
+
+  // Sort to make matching easy.
+  serviceProfiles.sort((a, b) => a.name.localeCompare(b.name));
+  profileData.profiles.sort((a, b) => a.name.localeCompare(b.name));
+
+  let hash = xreDirProvider.getInstallHash();
+  let defaultPath =
+    profileData.installs && hash in profileData.installs
+      ? profileData.installs[hash].default
+      : null;
+  let dedicatedProfile = null;
+  let legacyProfile = null;
+
+  for (let i = 0; i < serviceProfiles.length; i++) {
+    let serviceProfile = serviceProfiles[i];
+    let expectedProfile = profileData.profiles[i];
+
+    Assert.equal(
+      serviceProfile.name,
+      expectedProfile.name,
+      "Should have the same name."
+    );
+
+    let expectedPath = Cc["@mozilla.org/file/local;1"].createInstance(
+      Ci.nsIFile
+    );
+    expectedPath.setRelativeDescriptor(gDataHome, expectedProfile.path);
+    Assert.equal(
+      serviceProfile.rootDir.path,
+      expectedPath.path,
+      "Should have the same path."
+    );
+
+    if (expectedProfile.path == defaultPath) {
+      dedicatedProfile = serviceProfile;
+    }
+
+    if (AppConstants.MOZ_DEV_EDITION) {
+      if (expectedProfile.name == PROFILE_DEFAULT) {
+        legacyProfile = serviceProfile;
+      }
+    } else if (expectedProfile.default) {
+      legacyProfile = serviceProfile;
+    }
+  }
+
+  if (gIsLegacy || Services.env.get("SNAP_NAME")) {
+    Assert.equal(
+      service.defaultProfile,
+      legacyProfile,
+      "Should have seen the right profile selected."
+    );
+  } else {
+    Assert.equal(
+      service.defaultProfile,
+      dedicatedProfile,
+      "Should have seen the right profile selected."
+    );
+  }
+
+  if (verifyBackup) {
+    checkBackup(profileData);
+  }
+}
+
+// Maps the interesting scalar IDs to simple names that can be used as JS variables.
+const SCALARS = {
+  selectionReason: "startup.profile_selection_reason",
+  databaseVersion: "startup.profile_database_version",
+  profileCount: "startup.profile_count",
+};
+
+function getTelemetryScalars() {
+  let scalars = TelemetryTestUtils.getProcessScalars("parent");
+
+  let results = {};
+  for (let [prop, scalarId] of Object.entries(SCALARS)) {
+    results[prop] = scalars[scalarId];
+  }
+
+  return results;
+}
+
+function checkStartupReason(expected = undefined) {
+  let { selectionReason } = getTelemetryScalars();
+
+  Assert.equal(
+    selectionReason,
+    expected,
+    "Should have seen the right startup reason."
+  );
+}
diff --git a/toolkit/profile/xpcshell/test_check_backup.js b/toolkit/profile/xpcshell/test_check_backup.js
new file mode 100644
index 0000000000..2f5a9dbf18
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_check_backup.js
@@ -0,0 +1,56 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that when the profiles DB is missing the install data we reload it.
+ */
+
+add_task(async () => {
+  let hash = xreDirProvider.getInstallHash();
+
+  let profileData = {
+    options: {
+      startWithLastProfile: true,
+    },
+    profiles: [
+      {
+        name: "Profile1",
+        path: "Path1",
+      },
+      {
+        name: "Profile2",
+        path: "Path2",
+      },
+    ],
+  };
+
+  let installs = {
+    [hash]: {
+      default: "Path2",
+    },
+  };
+
+  writeProfilesIni(profileData);
+  writeInstallsIni({ installs });
+
+  let { profile, didCreate } = selectStartupProfile();
+  checkStartupReason("default");
+  let { databaseVersion, profileCount } = getTelemetryScalars();
+  Assert.equal(
+    databaseVersion,
+    "1",
+    "Old database file was present at startup."
+  );
+  Assert.equal(profileCount, 2, "Should be two profiles.");
+
+  // Should have added the backup data to the service, check that is true.
+  profileData.installs = installs;
+  checkProfileService(profileData);
+
+  Assert.ok(!didCreate, "Should not have created a new profile.");
+  Assert.equal(
+    profile.name,
+    "Profile2",
+    "Should have selected the right profile"
+  );
+});
diff --git a/toolkit/profile/xpcshell/test_claim_locked.js b/toolkit/profile/xpcshell/test_claim_locked.js
new file mode 100644
index 0000000000..bffdea39dc
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_claim_locked.js
@@ -0,0 +1,68 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that an old-style default profile already locked to a different install
+ * isn't claimed by this install.
+ */
+
+add_task(async () => {
+  let defaultProfile = makeRandomProfileDir("default");
+
+  writeCompatibilityIni(defaultProfile);
+
+  writeProfilesIni({
+    profiles: [
+      {
+        name: "Foo",
+        path: defaultProfile.leafName,
+        default: true,
+      },
+    ],
+    installs: {
+      other: {
+        default: defaultProfile.leafName,
+        locked: true,
+      },
+    },
+  });
+
+  let { profile: selectedProfile, didCreate } = selectStartupProfile();
+
+  let profileData = readProfilesIni();
+
+  Assert.ok(
+    profileData.options.startWithLastProfile,
+    "Should be set to start with the last profile."
+  );
+  Assert.equal(
+    profileData.profiles.length,
+    2,
+    "Should have the right number of profiles."
+  );
+
+  let hash = xreDirProvider.getInstallHash();
+  Assert.equal(
+    Object.keys(profileData.installs).length,
+    2,
+    "Should be two known installs."
+  );
+  Assert.notEqual(
+    profileData.installs[hash].default,
+    defaultProfile.leafName,
+    "Should not have marked the original default profile as the default for this install."
+  );
+  Assert.ok(
+    profileData.installs[hash].locked,
+    "Should have locked as we created this profile for this install."
+  );
+
+  checkProfileService(profileData);
+
+  Assert.ok(didCreate, "Should have created a new profile.");
+  Assert.ok(
+    !selectedProfile.rootDir.equals(defaultProfile),
+    "Should be using a different directory."
+  );
+  Assert.equal(selectedProfile.name, DEDICATED_NAME);
+});
diff --git a/toolkit/profile/xpcshell/test_clean.js b/toolkit/profile/xpcshell/test_clean.js
new file mode 100644
index 0000000000..3132d5457d
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_clean.js
@@ -0,0 +1,165 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests from a clean state.
+ * Then does some testing that creating new profiles and marking them as
+ * selected works.
+ */
+
+add_task(async () => {
+  let service = getProfileService();
+
+  let target = gDataHome.clone();
+  target.append("profiles.ini");
+  Assert.ok(!target.exists(), "profiles.ini should not exist yet.");
+  target.leafName = "installs.ini";
+  Assert.ok(!target.exists(), "installs.ini should not exist yet.");
+
+  // Create a new profile to use.
+  let newProfile = service.createProfile(null, "dedicated");
+  service.flush();
+
+  let profileData = readProfilesIni();
+
+  Assert.equal(
+    profileData.profiles.length,
+    1,
+    "Should have the right number of profiles."
+  );
+
+  let profile = profileData.profiles[0];
+  Assert.equal(profile.name, "dedicated", "Should have the right name.");
+  Assert.ok(!profile.default, "Should not be marked as the old-style default.");
+
+  // The new profile hasn't been marked as the default yet!
+  Assert.equal(
+    Object.keys(profileData.installs).length,
+    0,
+    "Should be no defaults for installs yet."
+  );
+
+  checkProfileService(profileData);
+
+  Assert.ok(
+    service.startWithLastProfile,
+    "Should be set to start with the last profile."
+  );
+  service.startWithLastProfile = false;
+  Assert.ok(
+    !service.startWithLastProfile,
+    "Should be set to not start with the last profile."
+  );
+
+  service.defaultProfile = newProfile;
+  service.flush();
+
+  profileData = readProfilesIni();
+
+  Assert.equal(
+    profileData.profiles.length,
+    1,
+    "Should have the right number of profiles."
+  );
+
+  profile = profileData.profiles[0];
+  Assert.equal(profile.name, "dedicated", "Should have the right name.");
+  Assert.ok(!profile.default, "Should not be marked as the old-style default.");
+
+  let hash = xreDirProvider.getInstallHash();
+  Assert.equal(
+    Object.keys(profileData.installs).length,
+    1,
+    "Should be only one known install."
+  );
+  Assert.equal(
+    profileData.installs[hash].default,
+    profileData.profiles[0].path,
+    "Should have marked the new profile as the default for this install."
+  );
+
+  checkProfileService(profileData);
+
+  let otherProfile = service.createProfile(null, "another");
+  service.defaultProfile = otherProfile;
+
+  service.flush();
+
+  profileData = readProfilesIni();
+
+  Assert.equal(
+    profileData.profiles.length,
+    2,
+    "Should have the right number of profiles."
+  );
+
+  profile = profileData.profiles[0];
+  Assert.equal(profile.name, "another", "Should have the right name.");
+  Assert.ok(!profile.default, "Should not be marked as the old-style default.");
+
+  profile = profileData.profiles[1];
+  Assert.equal(profile.name, "dedicated", "Should have the right name.");
+  Assert.ok(!profile.default, "Should not be marked as the old-style default.");
+
+  Assert.equal(
+    Object.keys(profileData.installs).length,
+    1,
+    "Should be only one known install."
+  );
+  Assert.equal(
+    profileData.installs[hash].default,
+    profileData.profiles[0].path,
+    "Should have marked the new profile as the default for this install."
+  );
+
+  checkProfileService(profileData);
+
+  newProfile.remove(true);
+  service.flush();
+
+  profileData = readProfilesIni();
+
+  Assert.equal(
+    profileData.profiles.length,
+    1,
+    "Should have the right number of profiles."
+  );
+
+  profile = profileData.profiles[0];
+  Assert.equal(profile.name, "another", "Should have the right name.");
+  Assert.ok(!profile.default, "Should not be marked as the old-style default.");
+
+  Assert.equal(
+    Object.keys(profileData.installs).length,
+    1,
+    "Should be only one known install."
+  );
+  Assert.equal(
+    profileData.installs[hash].default,
+    profileData.profiles[0].path,
+    "Should have marked the new profile as the default for this install."
+  );
+
+  checkProfileService(profileData);
+
+  otherProfile.remove(true);
+  service.flush();
+
+  profileData = readProfilesIni();
+
+  Assert.equal(
+    profileData.profiles.length,
+    0,
+    "Should have the right number of profiles."
+  );
+
+  // We leave a reference to the missing profile to stop us trying to steal the
+  // old-style default profile on next startup.
+  Assert.equal(
+    Object.keys(profileData.installs).length,
+    1,
+    "Should be only one known install."
+  );
+
+  checkProfileService(profileData);
+});
diff --git a/toolkit/profile/xpcshell/test_conflict_installs.js b/toolkit/profile/xpcshell/test_conflict_installs.js
new file mode 100644
index 0000000000..741e7ed70f
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_conflict_installs.js
@@ -0,0 +1,40 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that the profile service refuses to flush when the install.ini file
+ * has been modified.
+ */
+
+function check_unchanged(service) {
+  Assert.ok(
+    !service.isListOutdated,
+    "Should not have detected a modification."
+  );
+  try {
+    service.flush();
+    Assert.ok(true, "Should have flushed.");
+  } catch (e) {
+    Assert.ok(false, "Should have succeeded flushing.");
+  }
+}
+
+add_task(async () => {
+  let service = getProfileService();
+
+  Assert.ok(!service.isListOutdated, "Should not be modified yet.");
+
+  let installsini = gDataHome.clone();
+  installsini.append("installs.ini");
+
+  Assert.ok(!installsini.exists(), "File should not exist yet.");
+  installsini.create(Ci.nsIFile.NORMAL_FILE_TYPE, 0o644);
+
+  installsini.remove(false);
+  // We have to do profile selection to actually have any install data.
+  selectStartupProfile();
+  check_unchanged(service);
+
+  // We can't reset the modification time back to exactly what it was, so I
+  // guess we can't do much more here :(
+});
diff --git a/toolkit/profile/xpcshell/test_conflict_profiles.js b/toolkit/profile/xpcshell/test_conflict_profiles.js
new file mode 100644
index 0000000000..7028c1d5c2
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_conflict_profiles.js
@@ -0,0 +1,57 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that the profile service refuses to flush when the profiles.ini file
+ * has been modified.
+ */
+
+function check_unchanged(service) {
+  Assert.ok(
+    !service.isListOutdated,
+    "Should not have detected a modification."
+  );
+  try {
+    service.flush();
+    Assert.ok(true, "Should have flushed.");
+  } catch (e) {
+    Assert.ok(false, "Should have succeeded flushing.");
+  }
+}
+
+function check_outdated(service) {
+  Assert.ok(service.isListOutdated, "Should have detected a modification.");
+  try {
+    service.flush();
+    Assert.ok(false, "Should have failed to flush.");
+  } catch (e) {
+    Assert.equal(
+      e.result,
+      Cr.NS_ERROR_DATABASE_CHANGED,
+      "Should have refused to flush."
+    );
+  }
+}
+
+add_task(async () => {
+  let service = getProfileService();
+
+  Assert.ok(!service.isListOutdated, "Should not be modified yet.");
+
+  let profilesini = gDataHome.clone();
+  profilesini.append("profiles.ini");
+
+  Assert.ok(!profilesini.exists(), "File should not exist yet.");
+  profilesini.create(Ci.nsIFile.NORMAL_FILE_TYPE, 0o644);
+  check_outdated(service);
+
+  profilesini.remove(false);
+  check_unchanged(service);
+
+  let oldTime = profilesini.lastModifiedTime;
+  profilesini.lastModifiedTime = oldTime - 10000;
+  check_outdated(service);
+
+  // We can't reset the modification time back to exactly what it was, so I
+  // guess we can't do much more here :(
+});
diff --git a/toolkit/profile/xpcshell/test_create_default.js b/toolkit/profile/xpcshell/test_create_default.js
new file mode 100644
index 0000000000..cdac1832bf
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_create_default.js
@@ -0,0 +1,52 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that from an empty database a default profile is created.
+ */
+
+add_task(async () => {
+  let service = getProfileService();
+  let { profile, didCreate } = selectStartupProfile();
+
+  checkStartupReason("firstrun-created-default");
+
+  let profileData = readProfilesIni();
+  checkProfileService(profileData);
+
+  Assert.ok(didCreate, "Should have created a new profile.");
+  Assert.equal(
+    profile,
+    service.defaultProfile,
+    "Should now be the default profile."
+  );
+  Assert.equal(
+    profile.name,
+    DEDICATED_NAME,
+    "Should have created a new profile with the right name."
+  );
+
+  Assert.ok(
+    profileData.options.startWithLastProfile,
+    "Should be set to start with the last profile."
+  );
+  Assert.equal(
+    profileData.profiles.length,
+    2,
+    "Should have the right number of profiles."
+  );
+
+  profile = profileData.profiles[0];
+  Assert.equal(profile.name, "default", "Should have the right name.");
+  Assert.ok(profile.default, "Should be marked as the old-style default.");
+
+  profile = profileData.profiles[1];
+  Assert.equal(profile.name, DEDICATED_NAME, "Should have the right name.");
+  Assert.ok(!profile.default, "Should not be marked as the old-style default.");
+
+  let hash = xreDirProvider.getInstallHash();
+  Assert.ok(
+    profileData.installs[hash].locked,
+    "Should have locked the profile"
+  );
+});
diff --git a/toolkit/profile/xpcshell/test_fix_directory_case.js b/toolkit/profile/xpcshell/test_fix_directory_case.js
new file mode 100644
index 0000000000..60e3acbe4e
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_fix_directory_case.js
@@ -0,0 +1,113 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Tests the case where the user has an default profile set for the legacy
+ * install hash. This should be switched to the new hash and correctly used as
+ * the default.
+ */
+
+add_task(async () => {
+  let currentHash = xreDirProvider.getInstallHash();
+  let legacyHash = "F87E39E944FE466E";
+
+  let defaultProfile = makeRandomProfileDir("default");
+  let dedicatedProfile = makeRandomProfileDir("dedicated");
+  let devProfile = makeRandomProfileDir("devedition");
+
+  // Make sure we don't steal the old-style default.
+  writeCompatibilityIni(defaultProfile);
+
+  writeProfilesIni({
+    profiles: [
+      {
+        name: "default",
+        path: defaultProfile.leafName,
+        default: true,
+      },
+      {
+        name: "dedicated",
+        path: dedicatedProfile.leafName,
+      },
+      {
+        name: "dev-edition-default",
+        path: devProfile.leafName,
+      },
+    ],
+    installs: {
+      [legacyHash]: {
+        default: dedicatedProfile.leafName,
+      },
+      otherhash: {
+        default: "foobar",
+      },
+    },
+  });
+
+  let { profile: selectedProfile, didCreate } = selectStartupProfile(
+    [],
+    false,
+    legacyHash
+  );
+  checkStartupReason("default");
+
+  let profileData = readProfilesIni();
+
+  Assert.ok(
+    profileData.options.startWithLastProfile,
+    "Should be set to start with the last profile."
+  );
+  Assert.equal(
+    profileData.profiles.length,
+    3,
+    "Should have the right number of profiles."
+  );
+
+  let profile = profileData.profiles[0];
+  Assert.equal(profile.name, `dedicated`, "Should have the right name.");
+  Assert.equal(
+    profile.path,
+    dedicatedProfile.leafName,
+    "Should be the expected dedicated profile."
+  );
+  Assert.ok(!profile.default, "Should not be marked as the old-style default.");
+
+  profile = profileData.profiles[1];
+  Assert.equal(profile.name, "default", "Should have the right name.");
+  Assert.equal(
+    profile.path,
+    defaultProfile.leafName,
+    "Should be the original default profile."
+  );
+  Assert.ok(profile.default, "Should be marked as the old-style default.");
+
+  Assert.equal(
+    Object.keys(profileData.installs).length,
+    3,
+    "Should be three known installs."
+  );
+  Assert.equal(
+    profileData.installs[currentHash].default,
+    dedicatedProfile.leafName,
+    "Should have switched to the new install hash."
+  );
+  Assert.equal(
+    profileData.installs[legacyHash].default,
+    dedicatedProfile.leafName,
+    "Should have kept the old install hash."
+  );
+  Assert.equal(
+    profileData.installs.otherhash.default,
+    "foobar",
+    "Should have kept the default for the other install."
+  );
+
+  checkProfileService(profileData);
+
+  Assert.ok(!didCreate, "Should not have created a new profile.");
+  Assert.ok(
+    selectedProfile.rootDir.equals(dedicatedProfile),
+    "Should be using the right directory."
+  );
+  Assert.equal(selectedProfile.name, "dedicated");
+});
diff --git a/toolkit/profile/xpcshell/test_ignore_legacy_directory.js b/toolkit/profile/xpcshell/test_ignore_legacy_directory.js
new file mode 100644
index 0000000000..29b1601cc5
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_ignore_legacy_directory.js
@@ -0,0 +1,129 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Tests the case where the user has an default profile set for both the legacy
+ * and new install hash. This should just use the default for the new install
+ * hash.
+ */
+
+add_task(async () => {
+  let currentHash = xreDirProvider.getInstallHash();
+  let legacyHash = "F87E39E944FE466E";
+
+  let defaultProfile = makeRandomProfileDir("default");
+  let dedicatedProfile = makeRandomProfileDir("dedicated");
+  let devProfile = makeRandomProfileDir("devedition");
+
+  // Make sure we don't steal the old-style default.
+  writeCompatibilityIni(defaultProfile);
+
+  writeProfilesIni({
+    profiles: [
+      {
+        name: "default",
+        path: defaultProfile.leafName,
+        default: true,
+      },
+      {
+        name: "dedicated",
+        path: dedicatedProfile.leafName,
+      },
+      {
+        name: "dev-edition-default",
+        path: devProfile.leafName,
+      },
+    ],
+    installs: {
+      [legacyHash]: {
+        default: defaultProfile.leafName,
+      },
+      [currentHash]: {
+        default: dedicatedProfile.leafName,
+      },
+      otherhash: {
+        default: "foobar",
+      },
+    },
+  });
+
+  let { profile: selectedProfile, didCreate } = selectStartupProfile(
+    [],
+    false,
+    legacyHash
+  );
+  checkStartupReason("default");
+
+  let profileData = readProfilesIni();
+
+  Assert.ok(
+    profileData.options.startWithLastProfile,
+    "Should be set to start with the last profile."
+  );
+  Assert.equal(
+    profileData.profiles.length,
+    3,
+    "Should have the right number of profiles."
+  );
+
+  let profile = profileData.profiles[0];
+  Assert.equal(profile.name, `dedicated`, "Should have the right name.");
+  Assert.equal(
+    profile.path,
+    dedicatedProfile.leafName,
+    "Should be the expected dedicated profile."
+  );
+  Assert.ok(!profile.default, "Should not be marked as the old-style default.");
+
+  profile = profileData.profiles[1];
+  Assert.equal(profile.name, "default", "Should have the right name.");
+  Assert.equal(
+    profile.path,
+    defaultProfile.leafName,
+    "Should be the original default profile."
+  );
+  Assert.ok(profile.default, "Should be marked as the old-style default.");
+
+  profile = profileData.profiles[2];
+  Assert.equal(
+    profile.name,
+    "dev-edition-default",
+    "Should have the right name."
+  );
+  Assert.equal(
+    profile.path,
+    devProfile.leafName,
+    "Should not be the original default profile."
+  );
+  Assert.ok(!profile.default, "Should not be marked as the old-style default.");
+
+  Assert.equal(
+    Object.keys(profileData.installs).length,
+    3,
+    "Should be three known installs."
+  );
+  Assert.equal(
+    profileData.installs[currentHash].default,
+    dedicatedProfile.leafName,
+    "Should have switched to the new install hash."
+  );
+  Assert.equal(
+    profileData.installs[legacyHash].default,
+    defaultProfile.leafName,
+    "Should have ignored old install hash."
+  );
+  Assert.equal(
+    profileData.installs.otherhash.default,
+    "foobar",
+    "Should have kept the default for the other install."
+  );
+
+  checkProfileService(profileData);
+
+  Assert.ok(!didCreate, "Should not have created a new profile.");
+  Assert.ok(
+    selectedProfile.rootDir.equals(dedicatedProfile),
+    "Should be using the right directory."
+  );
+  Assert.equal(selectedProfile.name, "dedicated");
+});
diff --git a/toolkit/profile/xpcshell/test_invalid_descriptor.js b/toolkit/profile/xpcshell/test_invalid_descriptor.js
new file mode 100644
index 0000000000..87638d301d
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_invalid_descriptor.js
@@ -0,0 +1,55 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * If a user has modified a relative profile path then there may be issues where
+ * the profile default setting doesn't match.
+ */
+
+add_task(async () => {
+  let hash = xreDirProvider.getInstallHash();
+
+  let profileData = {
+    options: {
+      startWithLastProfile: true,
+    },
+    profiles: [
+      {
+        name: "Profile1",
+        path: "../data/test",
+      },
+      {
+        name: "Profile2",
+        path: "Path2",
+      },
+    ],
+    installs: {
+      [hash]: {
+        default: "test",
+      },
+    },
+  };
+
+  writeProfilesIni(profileData);
+
+  let { profile, didCreate } = selectStartupProfile();
+  checkStartupReason("default");
+
+  let service = getProfileService();
+
+  Assert.ok(!didCreate, "Should not have created a new profile.");
+  Assert.equal(
+    profile.name,
+    "Profile1",
+    "Should have selected the expected profile"
+  );
+
+  Assert.equal(
+    profile.name,
+    service.defaultProfile.name,
+    "Should have selected the right default."
+  );
+
+  service.flush();
+  checkProfileService();
+});
diff --git a/toolkit/profile/xpcshell/test_legacy_empty.js b/toolkit/profile/xpcshell/test_legacy_empty.js
new file mode 100644
index 0000000000..7348006f8b
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_legacy_empty.js
@@ -0,0 +1,28 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that setting MOZ_LEGACY_PROFILES disables dedicated profiles.
+ */
+
+add_task(async () => {
+  enableLegacyProfiles();
+
+  let service = getProfileService();
+  let { profile, didCreate } = selectStartupProfile();
+  checkStartupReason("firstrun-created-default");
+
+  Assert.ok(didCreate, "Should have created a new profile.");
+  Assert.equal(
+    profile.name,
+    PROFILE_DEFAULT,
+    "Should have used the normal name."
+  );
+  if (AppConstants.MOZ_DEV_EDITION) {
+    Assert.equal(service.profileCount, 2, "Should be two profiles.");
+  } else {
+    Assert.equal(service.profileCount, 1, "Should be only one profile.");
+  }
+
+  checkProfileService();
+});
diff --git a/toolkit/profile/xpcshell/test_legacy_select.js b/toolkit/profile/xpcshell/test_legacy_select.js
new file mode 100644
index 0000000000..e919169d59
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_legacy_select.js
@@ -0,0 +1,67 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that an old-style default profile not previously used by this build
+ * gets selected when configured for legacy profiles.
+ */
+
+add_task(async () => {
+  let defaultProfile = makeRandomProfileDir("default");
+
+  // Just pretend this profile was last used by something in the profile dir.
+  let greDir = gProfD.clone();
+  greDir.append("app");
+  writeCompatibilityIni(defaultProfile, greDir, greDir);
+
+  writeProfilesIni({
+    profiles: [
+      {
+        name: PROFILE_DEFAULT,
+        path: defaultProfile.leafName,
+        default: true,
+      },
+    ],
+  });
+
+  enableLegacyProfiles();
+
+  let { profile: selectedProfile, didCreate } = selectStartupProfile();
+  checkStartupReason("default");
+
+  let profileData = readProfilesIni();
+  let installsINI = gDataHome.clone();
+  installsINI.append("installs.ini");
+  Assert.ok(
+    !installsINI.exists(),
+    "Installs database should not have been created."
+  );
+
+  Assert.ok(
+    profileData.options.startWithLastProfile,
+    "Should be set to start with the last profile."
+  );
+  Assert.equal(
+    profileData.profiles.length,
+    1,
+    "Should have the right number of profiles."
+  );
+
+  let profile = profileData.profiles[0];
+  Assert.equal(profile.name, PROFILE_DEFAULT, "Should have the right name.");
+  Assert.equal(
+    profile.path,
+    defaultProfile.leafName,
+    "Should be the original default profile."
+  );
+  Assert.ok(profile.default, "Should be marked as the old-style default.");
+
+  checkProfileService(profileData);
+
+  Assert.ok(!didCreate, "Should not have created a new profile.");
+  Assert.ok(
+    selectedProfile.rootDir.equals(defaultProfile),
+    "Should be using the right directory."
+  );
+  Assert.equal(selectedProfile.name, PROFILE_DEFAULT);
+});
diff --git a/toolkit/profile/xpcshell/test_lock.js b/toolkit/profile/xpcshell/test_lock.js
new file mode 100644
index 0000000000..7283406e00
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_lock.js
@@ -0,0 +1,72 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that when the default application claims the old-style default profile
+ * it locks it to itself.
+ */
+
+add_task(async () => {
+  gIsDefaultApp = true;
+  let defaultProfile = makeRandomProfileDir("default");
+
+  writeCompatibilityIni(defaultProfile);
+
+  writeProfilesIni({
+    profiles: [
+      {
+        name: PROFILE_DEFAULT,
+        path: defaultProfile.leafName,
+        default: true,
+      },
+    ],
+  });
+
+  let { profile: selectedProfile, didCreate } = selectStartupProfile();
+
+  let hash = xreDirProvider.getInstallHash();
+  let profileData = readProfilesIni();
+
+  Assert.ok(
+    profileData.options.startWithLastProfile,
+    "Should be set to start with the last profile."
+  );
+  Assert.equal(
+    profileData.profiles.length,
+    1,
+    "Should have the right number of profiles."
+  );
+
+  let profile = profileData.profiles[0];
+  Assert.equal(profile.name, PROFILE_DEFAULT, "Should have the right name.");
+  Assert.equal(
+    profile.path,
+    defaultProfile.leafName,
+    "Should be the original default profile."
+  );
+  Assert.ok(profile.default, "Should be marked as the old-style default.");
+
+  Assert.equal(
+    Object.keys(profileData.installs).length,
+    1,
+    "Should be only one known install."
+  );
+  Assert.equal(
+    profileData.installs[hash].default,
+    defaultProfile.leafName,
+    "Should have marked the original default profile as the default for this install."
+  );
+  Assert.ok(
+    profileData.installs[hash].locked,
+    "Should have locked as we're the default app."
+  );
+
+  checkProfileService(profileData);
+
+  Assert.ok(!didCreate, "Should not have created a new profile.");
+  Assert.ok(
+    selectedProfile.rootDir.equals(defaultProfile),
+    "Should be using the right directory."
+  );
+  Assert.equal(selectedProfile.name, PROFILE_DEFAULT);
+});
diff --git a/toolkit/profile/xpcshell/test_missing_profilesini.js b/toolkit/profile/xpcshell/test_missing_profilesini.js
new file mode 100644
index 0000000000..74ab7584fa
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_missing_profilesini.js
@@ -0,0 +1,67 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * When profiles.ini is missing there isn't any point in restoring from any
+ * installs.ini, the profiles it refers to are gone anyway.
+ */
+
+add_task(async () => {
+  let hash = xreDirProvider.getInstallHash();
+
+  let installs = {
+    [hash]: {
+      default: "Path2",
+    },
+    otherhash: {
+      default: "foo",
+    },
+    anotherhash: {
+      default: "bar",
+    },
+  };
+
+  writeInstallsIni({ installs });
+
+  let { profile, didCreate } = selectStartupProfile();
+  checkStartupReason("firstrun-created-default");
+
+  Assert.ok(didCreate, "Should have created a new profile.");
+  Assert.equal(
+    profile.name,
+    DEDICATED_NAME,
+    "Should have created the right profile"
+  );
+
+  let profilesData = readProfilesIni();
+  Assert.equal(
+    Object.keys(profilesData.installs).length,
+    1,
+    "Should be only one known install"
+  );
+  Assert.ok(hash in profilesData.installs, "Should be the expected install.");
+  Assert.notEqual(
+    profilesData.installs[hash].default,
+    "Path2",
+    "Didn't import the previous data."
+  );
+  Assert.equal(
+    profilesData.profiles.length,
+    2,
+    "Should be two profiles (old-style default and dedicated default)."
+  );
+
+  let { databaseVersion, profileCount } = getTelemetryScalars();
+  Assert.equal(
+    databaseVersion,
+    "0",
+    "Database file was not present at startup."
+  );
+  Assert.equal(
+    profileCount,
+    2,
+    "Should be two profiles (old-style default and dedicated default)."
+  );
+
+  checkProfileService(profilesData);
+});
diff --git a/toolkit/profile/xpcshell/test_new_default.js b/toolkit/profile/xpcshell/test_new_default.js
new file mode 100644
index 0000000000..552433ab95
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_new_default.js
@@ -0,0 +1,129 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that an old-style default profile previously used by this build gets
+ * updated to a dedicated profile for this build.
+ */
+
+add_task(async () => {
+  let mydefaultProfile = makeRandomProfileDir("mydefault");
+  let defaultProfile = makeRandomProfileDir("default");
+  let devDefaultProfile = makeRandomProfileDir("devedition");
+
+  writeCompatibilityIni(mydefaultProfile);
+  writeCompatibilityIni(devDefaultProfile);
+
+  writeProfilesIni({
+    profiles: [
+      {
+        name: "mydefault",
+        path: mydefaultProfile.leafName,
+        default: true,
+      },
+      {
+        name: "default",
+        path: defaultProfile.leafName,
+      },
+      {
+        name: "dev-edition-default",
+        path: devDefaultProfile.leafName,
+      },
+    ],
+  });
+
+  let { profile: selectedProfile, didCreate } = selectStartupProfile();
+  checkStartupReason("firstrun-claimed-default");
+  let { databaseVersion, profileCount } = getTelemetryScalars();
+  Assert.equal(
+    databaseVersion,
+    "1",
+    "Old database file was present at startup."
+  );
+  Assert.equal(profileCount, 3, "Should be three profiles.");
+
+  let hash = xreDirProvider.getInstallHash();
+  let profileData = readProfilesIni();
+
+  Assert.ok(
+    profileData.options.startWithLastProfile,
+    "Should be set to start with the last profile."
+  );
+  Assert.equal(
+    profileData.profiles.length,
+    3,
+    "Should have the right number of profiles."
+  );
+
+  let profile = profileData.profiles[0];
+  Assert.equal(profile.name, "default", "Should have the right name.");
+  Assert.equal(
+    profile.path,
+    defaultProfile.leafName,
+    "Should be the original non-default profile."
+  );
+  Assert.ok(!profile.default, "Should not be marked as the old-style default.");
+
+  profile = profileData.profiles[1];
+  Assert.equal(
+    profile.name,
+    "dev-edition-default",
+    "Should have the right name."
+  );
+  Assert.equal(
+    profile.path,
+    devDefaultProfile.leafName,
+    "Should be the original dev default profile."
+  );
+  Assert.ok(!profile.default, "Should not be marked as the old-style default.");
+
+  profile = profileData.profiles[2];
+  Assert.equal(profile.name, "mydefault", "Should have the right name.");
+  Assert.equal(
+    profile.path,
+    mydefaultProfile.leafName,
+    "Should be the original default profile."
+  );
+  Assert.ok(profile.default, "Should be marked as the old-style default.");
+
+  Assert.equal(
+    Object.keys(profileData.installs).length,
+    1,
+    "Should be only one known install."
+  );
+  if (AppConstants.MOZ_DEV_EDITION) {
+    Assert.equal(
+      profileData.installs[hash].default,
+      devDefaultProfile.leafName,
+      "Should have marked the original dev default profile as the default for this install."
+    );
+  } else {
+    Assert.equal(
+      profileData.installs[hash].default,
+      mydefaultProfile.leafName,
+      "Should have marked the original default profile as the default for this install."
+    );
+  }
+
+  Assert.ok(
+    !profileData.installs[hash].locked,
+    "Should not be locked as we're not the default app."
+  );
+
+  checkProfileService(profileData);
+
+  Assert.ok(!didCreate, "Should not have created a new profile.");
+  if (AppConstants.MOZ_DEV_EDITION) {
+    Assert.ok(
+      selectedProfile.rootDir.equals(devDefaultProfile),
+      "Should be using the right directory."
+    );
+    Assert.equal(selectedProfile.name, "dev-edition-default");
+  } else {
+    Assert.ok(
+      selectedProfile.rootDir.equals(mydefaultProfile),
+      "Should be using the right directory."
+    );
+    Assert.equal(selectedProfile.name, "mydefault");
+  }
+});
diff --git a/toolkit/profile/xpcshell/test_previous_dedicated.js b/toolkit/profile/xpcshell/test_previous_dedicated.js
new file mode 100644
index 0000000000..6dd80b4028
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_previous_dedicated.js
@@ -0,0 +1,62 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * If install.ini lists a default profile for this build but that profile no
+ * longer exists don't try to steal the old-style default even if it was used
+ * by this build. It means this install has previously used dedicated profiles.
+ */
+
+add_task(async () => {
+  let hash = xreDirProvider.getInstallHash();
+  let defaultProfile = makeRandomProfileDir("default");
+
+  writeCompatibilityIni(defaultProfile);
+
+  writeProfilesIni({
+    profiles: [
+      {
+        name: "default",
+        path: defaultProfile.leafName,
+        default: true,
+      },
+    ],
+    installs: {
+      [hash]: {
+        default: "foobar",
+      },
+    },
+  });
+
+  testStartsProfileManager();
+
+  let profileData = readProfilesIni();
+
+  Assert.ok(
+    profileData.options.startWithLastProfile,
+    "Should be set to start with the last profile."
+  );
+  Assert.equal(
+    profileData.profiles.length,
+    1,
+    "Should have the right number of profiles."
+  );
+
+  let profile = profileData.profiles[0];
+  Assert.equal(profile.name, "default", "Should have the right name.");
+  Assert.equal(
+    profile.path,
+    defaultProfile.leafName,
+    "Should be the original default profile."
+  );
+  Assert.ok(profile.default, "Should be marked as the old-style default.");
+
+  // We keep the data here so we don't steal on the next reboot...
+  Assert.equal(
+    Object.keys(profileData.installs).length,
+    1,
+    "Still list the broken reference."
+  );
+
+  checkProfileService(profileData);
+});
diff --git a/toolkit/profile/xpcshell/test_profile_reset.js b/toolkit/profile/xpcshell/test_profile_reset.js
new file mode 100644
index 0000000000..7cfb5ed3d1
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_profile_reset.js
@@ -0,0 +1,59 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that from an empty database with profile reset requested a new profile
+ * is still created.
+ */
+
+add_task(async () => {
+  let { profile: selectedProfile, didCreate } = selectStartupProfile([], true);
+  // With no profile we're just create a new profile and skip resetting it.
+  checkStartupReason("firstrun-created-default");
+  checkProfileService();
+
+  let hash = xreDirProvider.getInstallHash();
+  let profileData = readProfilesIni();
+
+  Assert.ok(
+    profileData.options.startWithLastProfile,
+    "Should be set to start with the last profile."
+  );
+  Assert.equal(
+    profileData.profiles.length,
+    2,
+    "Should have the right number of profiles, ours and the old-style default."
+  );
+
+  let profile = profileData.profiles[0];
+  Assert.equal(profile.name, "default", "Should have the right name.");
+  Assert.ok(profile.default, "Should be marked as the old-style default.");
+
+  profile = profileData.profiles[1];
+  Assert.equal(profile.name, DEDICATED_NAME, "Should have the right name.");
+  Assert.ok(!profile.default, "Should not be marked as the old-style default.");
+
+  Assert.equal(
+    Object.keys(profileData.installs).length,
+    1,
+    "Should only be one known installs."
+  );
+  Assert.equal(
+    profileData.installs[hash].default,
+    profile.path,
+    "Should have taken the new profile as the default for the current install."
+  );
+  Assert.ok(
+    profileData.installs[hash].locked,
+    "Should have locked as we created this profile."
+  );
+
+  checkProfileService(profileData);
+
+  Assert.ok(didCreate, "Should have created a new profile.");
+  Assert.equal(
+    selectedProfile.name,
+    profile.name,
+    "Should be using the right profile."
+  );
+});
diff --git a/toolkit/profile/xpcshell/test_remove.js b/toolkit/profile/xpcshell/test_remove.js
new file mode 100644
index 0000000000..8b5025d612
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_remove.js
@@ -0,0 +1,103 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests adding and removing functions correctly.
+ */
+
+function compareLists(service, knownProfiles) {
+  Assert.equal(
+    service.profileCount,
+    knownProfiles.length,
+    "profileCount should be correct."
+  );
+  let serviceProfiles = Array.from(service.profiles);
+  Assert.equal(
+    serviceProfiles.length,
+    knownProfiles.length,
+    "Enumerator length should be correct."
+  );
+
+  for (let i = 0; i < knownProfiles.length; i++) {
+    // Cannot use strictEqual here, it attempts to print out a string
+    // representation of the profile objects and on some platforms that recurses
+    // infinitely.
+    Assert.ok(
+      serviceProfiles[i] === knownProfiles[i],
+      `Should have the right profile in position ${i}.`
+    );
+  }
+}
+
+function removeProfile(profiles, position) {
+  dump(`Removing profile in position ${position}.`);
+  Assert.greaterOrEqual(position, 0, "Should be removing a valid position.");
+  Assert.less(
+    position,
+    profiles.length,
+    "Should be removing a valid position."
+  );
+
+  let last = profiles.pop();
+
+  if (profiles.length == position) {
+    // We were asked to remove the last profile.
+    last.remove(false);
+    return;
+  }
+
+  profiles[position].remove(false);
+  profiles[position] = last;
+}
+
+add_task(async () => {
+  let service = getProfileService();
+  let profiles = [];
+  compareLists(service, profiles);
+
+  profiles.push(service.createProfile(null, "profile1"));
+  profiles.push(service.createProfile(null, "profile2"));
+  profiles.push(service.createProfile(null, "profile3"));
+  profiles.push(service.createProfile(null, "profile4"));
+  profiles.push(service.createProfile(null, "profile5"));
+  profiles.push(service.createProfile(null, "profile6"));
+  profiles.push(service.createProfile(null, "profile7"));
+  profiles.push(service.createProfile(null, "profile8"));
+  profiles.push(service.createProfile(null, "profile9"));
+  compareLists(service, profiles);
+
+  // Test removing the first profile.
+  removeProfile(profiles, 0);
+  compareLists(service, profiles);
+
+  // And the last profile.
+  removeProfile(profiles, profiles.length - 1);
+  compareLists(service, profiles);
+
+  // Last but one...
+  removeProfile(profiles, profiles.length - 2);
+  compareLists(service, profiles);
+
+  // Second one...
+  removeProfile(profiles, 1);
+  compareLists(service, profiles);
+
+  // Something in the middle.
+  removeProfile(profiles, 2);
+  compareLists(service, profiles);
+
+  let expectedNames = ["profile9", "profile7", "profile5", "profile4"];
+
+  let serviceProfiles = Array.from(service.profiles);
+  for (let i = 0; i < expectedNames.length; i++) {
+    Assert.equal(serviceProfiles[i].name, expectedNames[i]);
+  }
+
+  removeProfile(profiles, 0);
+  removeProfile(profiles, 0);
+  removeProfile(profiles, 0);
+  removeProfile(profiles, 0);
+
+  Assert.equal(Array.from(service.profiles).length, 0, "All profiles gone.");
+  Assert.equal(service.profileCount, 0, "All profiles gone.");
+});
diff --git a/toolkit/profile/xpcshell/test_remove_default.js b/toolkit/profile/xpcshell/test_remove_default.js
new file mode 100644
index 0000000000..f77f2d87d9
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_remove_default.js
@@ -0,0 +1,79 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Tests that calling nsIToolkitProfile.remove on the default profile correctly
+ * removes the profile.
+ */
+
+add_task(async () => {
+  let hash = xreDirProvider.getInstallHash();
+  let defaultProfile = makeRandomProfileDir("default");
+
+  let profilesIni = {
+    profiles: [
+      {
+        name: "default",
+        path: defaultProfile.leafName,
+        default: true,
+      },
+    ],
+    installs: {
+      [hash]: {
+        default: defaultProfile.leafName,
+      },
+    },
+  };
+  writeProfilesIni(profilesIni);
+
+  let service = getProfileService();
+  checkProfileService(profilesIni);
+
+  let { profile, didCreate } = selectStartupProfile();
+  Assert.ok(!didCreate, "Should have not created a new profile.");
+  Assert.equal(
+    profile.name,
+    "default",
+    "Should have selected the default profile."
+  );
+  Assert.equal(
+    profile,
+    service.defaultProfile,
+    "Should have selected the default profile."
+  );
+
+  checkProfileService(profilesIni);
+
+  // In an actual run of Firefox we wouldn't be able to delete the profile in
+  // use because it would be locked. But we don't actually lock the profile in
+  // tests.
+  profile.remove(false);
+
+  Assert.ok(!service.defaultProfile, "Should no longer be a default profile.");
+  Assert.equal(
+    profile,
+    service.currentProfile,
+    "Should still be the profile in use."
+  );
+
+  // These are the modifications that should have been made.
+  profilesIni.profiles.pop();
+  profilesIni.installs[hash].default = "";
+
+  // The data isn't flushed to disk so don't check the backup here.
+  checkProfileService(profilesIni, false);
+
+  service.flush();
+
+  // And that should have flushed to disk correctly.
+  checkProfileService();
+
+  // checkProfileService doesn't differentiate between a blank default profile
+  // for the install and a missing install.
+  profilesIni = readProfilesIni();
+  Assert.equal(
+    profilesIni.installs[hash].default,
+    "",
+    "Should be a blank default profile."
+  );
+});
diff --git a/toolkit/profile/xpcshell/test_select_backgroundtasks_ephemeral.js b/toolkit/profile/xpcshell/test_select_backgroundtasks_ephemeral.js
new file mode 100644
index 0000000000..982df276db
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_select_backgroundtasks_ephemeral.js
@@ -0,0 +1,30 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Verify that background tasks don't touch `profiles.ini` for ephemeral profile
+ * tasks.
+ */
+
+let condition = {
+  skip_if: () => !AppConstants.MOZ_BACKGROUNDTASKS,
+};
+
+add_task(condition, async () => {
+  writeProfilesIni(BACKGROUNDTASKS_PROFILE_DATA);
+
+  // Pretend that this is a background task.  For a task that uses an ephemeral
+  // profile, `profiles.ini` is untouched.
+  const bts = Cc["@mozilla.org/backgroundtasks;1"].getService(
+    Ci.nsIBackgroundTasks
+  );
+  bts.overrideBackgroundTaskNameForTesting("ephemeral_profile");
+
+  let { didCreate } = selectStartupProfile();
+  checkStartupReason("backgroundtask-ephemeral");
+
+  Assert.equal(didCreate, true, "Created new ephemeral profile");
+
+  let profileData = readProfilesIni();
+  Assert.deepEqual(BACKGROUNDTASKS_PROFILE_DATA, profileData);
+});
diff --git a/toolkit/profile/xpcshell/test_select_backgroundtasks_not_ephemeral_create.js b/toolkit/profile/xpcshell/test_select_backgroundtasks_not_ephemeral_create.js
new file mode 100644
index 0000000000..ebed889360
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_select_backgroundtasks_not_ephemeral_create.js
@@ -0,0 +1,78 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Verify that background tasks that create non-ephemeral profiles update
+ * `profiles.ini` with a salted profile location.
+ */
+
+let condition = {
+  skip_if: () => !AppConstants.MOZ_BACKGROUNDTASKS,
+};
+
+// MOZ_APP_VENDOR is empty on Thunderbird.
+let vendor = AppConstants.MOZ_APP_NAME == "thunderbird" ? "" : "Mozilla";
+
+add_task(condition, async () => {
+  let hash = xreDirProvider.getInstallHash();
+
+  writeProfilesIni(BACKGROUNDTASKS_PROFILE_DATA);
+
+  // Pretend that this is a background task.  For a task that does *not* use an
+  // ephemeral profile, i.e., that uses a persistent profile, `profiles.ini` is
+  // updated with a new entry in section `BackgroundTaskProfiles`.
+  const bts = Cc["@mozilla.org/backgroundtasks;1"].getService(
+    Ci.nsIBackgroundTasks
+  );
+  // "not_ephemeral_profile" is a special name recognized by the
+  // background task system.
+  bts.overrideBackgroundTaskNameForTesting("not_ephemeral_profile");
+
+  let { didCreate, rootDir } = selectStartupProfile();
+  checkStartupReason("backgroundtask-not-ephemeral");
+
+  Assert.equal(didCreate, true, "Created new non-ephemeral profile");
+
+  let profileData = readProfilesIni();
+
+  // Profile names are lexicographically ordered, and `not_ephemeral_profile`
+  // sorts before `unrelated_task`.
+  Assert.equal(profileData.backgroundTasksProfiles.length, 2);
+  Assert.deepEqual(
+    [profileData.backgroundTasksProfiles[1]],
+    BACKGROUNDTASKS_PROFILE_DATA.backgroundTasksProfiles
+  );
+
+  let saltedPath = profileData.backgroundTasksProfiles[0].path;
+  Assert.ok(
+    saltedPath.endsWith(
+      `.${vendor}BackgroundTask-${hash}-not_ephemeral_profile`
+    ),
+    `${saltedPath} ends with ".${vendor}BackgroundTask-${hash}-not_ephemeral_profile"`
+  );
+  Assert.ok(
+    !saltedPath.startsWith(
+      `.${vendor}BackgroundTask-${hash}-not_ephemeral_profile`
+    ),
+    `${saltedPath} is really salted`
+  );
+  Assert.deepEqual(profileData.backgroundTasksProfiles[0], {
+    name: `${vendor}BackgroundTask-${hash}-not_ephemeral_profile`,
+    path: saltedPath,
+  });
+
+  Assert.ok(
+    rootDir.path.endsWith(saltedPath),
+    `rootDir "${rootDir.path}" ends with salted path "${saltedPath}"`
+  );
+
+  // Really, "UAppData", but this is xpcshell.
+  let backgroundTasksProfilesPath = gDataHome;
+  if (!AppConstants.XP_UNIX || AppConstants.platform === "macosx") {
+    backgroundTasksProfilesPath.append("Background Tasks Profiles");
+  }
+  Assert.ok(
+    rootDir.path.startsWith(backgroundTasksProfilesPath.path),
+    `rootDir "${rootDir.path}" is sibling to user profiles directory ${backgroundTasksProfilesPath}`
+  );
+});
diff --git a/toolkit/profile/xpcshell/test_select_backgroundtasks_not_ephemeral_exists.js b/toolkit/profile/xpcshell/test_select_backgroundtasks_not_ephemeral_exists.js
new file mode 100644
index 0000000000..6fa3ec5882
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_select_backgroundtasks_not_ephemeral_exists.js
@@ -0,0 +1,66 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Verify that background tasks that use non-ephemeral profiles re-use existing
+ * salted profile locations from `profiles.ini`.
+ */
+
+let condition = {
+  skip_if: () => !AppConstants.MOZ_BACKGROUNDTASKS,
+};
+
+// MOZ_APP_VENDOR is empty on Thunderbird.
+let vendor = AppConstants.MOZ_APP_NAME == "thunderbird" ? "" : "Mozilla";
+
+add_task(condition, async () => {
+  let hash = xreDirProvider.getInstallHash();
+
+  let saltedPath = `saltSALT.${vendor}BackgroundTask-${hash}-not_ephemeral_profile`;
+
+  // See note about ordering below.
+  BACKGROUNDTASKS_PROFILE_DATA.backgroundTasksProfiles.splice(0, 0, {
+    name: `${vendor}BackgroundTask-${hash}-not_ephemeral_profile`,
+    path: saltedPath,
+  });
+
+  writeProfilesIni(BACKGROUNDTASKS_PROFILE_DATA);
+
+  // Pretend that this is a background task.  For a task that does *not* use an
+  // ephemeral profile, i.e., that uses a persistent profile, when
+  // `profiles.ini` section `BackgroundTasksProfiles` contains the relevant
+  // entry, that profile path is re-used.
+  const bts = Cc["@mozilla.org/backgroundtasks;1"].getService(
+    Ci.nsIBackgroundTasks
+  );
+  // "not_ephemeral_profile" is a special name recognized by the
+  // background task system.
+  bts.overrideBackgroundTaskNameForTesting("not_ephemeral_profile");
+
+  let { didCreate, rootDir } = selectStartupProfile();
+  checkStartupReason("backgroundtask-not-ephemeral");
+
+  Assert.equal(didCreate, false, "Re-used existing non-ephemeral profile");
+
+  let profileData = readProfilesIni();
+
+  // Profile names are lexicographically ordered, and `not_ephemeral_profile`
+  // sorts before `unrelated_task`.
+  Assert.equal(profileData.backgroundTasksProfiles.length, 2);
+  Assert.deepEqual(profileData, BACKGROUNDTASKS_PROFILE_DATA);
+
+  Assert.ok(
+    rootDir.path.endsWith(saltedPath),
+    `rootDir "${rootDir.path}" ends with salted path "${saltedPath}"`
+  );
+
+  // Really, "UAppData", but this is xpcshell.
+  let backgroundTasksProfilesPath = gDataHome;
+  if (!AppConstants.XP_UNIX || AppConstants.platform === "macosx") {
+    backgroundTasksProfilesPath.append("Background Tasks Profiles");
+  }
+  Assert.ok(
+    rootDir.path.startsWith(backgroundTasksProfilesPath.path),
+    `rootDir "${rootDir.path}" is sibling to user profiles directory ${backgroundTasksProfilesPath}`
+  );
+});
diff --git a/toolkit/profile/xpcshell/test_select_default.js b/toolkit/profile/xpcshell/test_select_default.js
new file mode 100644
index 0000000000..df4b27df7e
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_select_default.js
@@ -0,0 +1,71 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that from a database of profiles the default profile is selected.
+ */
+
+add_task(async () => {
+  let hash = xreDirProvider.getInstallHash();
+
+  let profileData = {
+    options: {
+      startWithLastProfile: true,
+    },
+    profiles: [
+      {
+        name: "Profile1",
+        path: "Path1",
+      },
+      {
+        name: "Profile3",
+        path: "Path3",
+      },
+    ],
+    installs: {
+      [hash]: {
+        default: "Path2",
+      },
+    },
+  };
+
+  if (AppConstants.MOZ_DEV_EDITION) {
+    profileData.profiles.push(
+      {
+        name: "default",
+        path: "Path2",
+        default: true,
+      },
+      {
+        name: PROFILE_DEFAULT,
+        path: "Path4",
+      }
+    );
+  } else {
+    profileData.profiles.push({
+      name: PROFILE_DEFAULT,
+      path: "Path2",
+      default: true,
+    });
+  }
+
+  writeProfilesIni(profileData);
+
+  let { profile, didCreate } = selectStartupProfile();
+  checkStartupReason("default");
+
+  let service = getProfileService();
+  checkProfileService(profileData);
+
+  Assert.ok(!didCreate, "Should not have created a new profile.");
+  Assert.equal(
+    profile,
+    service.defaultProfile,
+    "Should have returned the default profile."
+  );
+  Assert.equal(
+    profile.name,
+    "default",
+    "Should have selected the right profile"
+  );
+});
diff --git a/toolkit/profile/xpcshell/test_select_environment.js b/toolkit/profile/xpcshell/test_select_environment.js
new file mode 100644
index 0000000000..f7e3138191
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_select_environment.js
@@ -0,0 +1,45 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that the environment variables are used to select a profile.
+ */
+
+add_task(async () => {
+  let dir = makeRandomProfileDir("foo");
+
+  let profileData = {
+    options: {
+      startWithLastProfile: true,
+    },
+    profiles: [
+      {
+        name: "Profile1",
+        path: dir.leafName,
+      },
+      {
+        name: "Profile2",
+        path: "Path2",
+        default: true,
+      },
+      {
+        name: "Profile3",
+        path: "Path3",
+      },
+    ],
+  };
+
+  writeProfilesIni(profileData);
+  checkProfileService(profileData);
+
+  Services.env.set("XRE_PROFILE_PATH", dir.path);
+  Services.env.set("XRE_PROFILE_LOCAL_PATH", dir.path);
+
+  let { rootDir, localDir, profile, didCreate } = selectStartupProfile();
+  checkStartupReason("restart");
+
+  Assert.ok(!didCreate, "Should not have created a new profile.");
+  Assert.ok(rootDir.equals(dir), "Should have selected the right root dir.");
+  Assert.ok(localDir.equals(dir), "Should have selected the right local dir.");
+  Assert.ok(!profile, "No named profile matches this.");
+});
diff --git a/toolkit/profile/xpcshell/test_select_environment_named.js b/toolkit/profile/xpcshell/test_select_environment_named.js
new file mode 100644
index 0000000000..348ce0ff0a
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_select_environment_named.js
@@ -0,0 +1,61 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that the environment variables are used to select a profile.
+ */
+
+add_task(async () => {
+  let root = makeRandomProfileDir("foo");
+  let local = gDataHomeLocal.clone();
+  local.append("foo");
+
+  let profileData = {
+    options: {
+      startWithLastProfile: true,
+    },
+    profiles: [
+      {
+        name: "Profile1",
+        path: root.leafName,
+      },
+      {
+        name: "Profile2",
+        path: "Path2",
+        default: true,
+      },
+      {
+        name: "Profile3",
+        path: "Path3",
+      },
+    ],
+  };
+
+  writeProfilesIni(profileData);
+  checkProfileService(profileData);
+
+  Services.env.set("XRE_PROFILE_PATH", root.path);
+  Services.env.set("XRE_PROFILE_LOCAL_PATH", local.path);
+
+  let { rootDir, localDir, profile, didCreate } = selectStartupProfile([
+    "-P",
+    "Profile3",
+  ]);
+  checkStartupReason("restart");
+
+  Assert.ok(!didCreate, "Should not have created a new profile.");
+  Assert.ok(rootDir.equals(root), "Should have selected the right root dir.");
+  Assert.ok(
+    localDir.equals(local),
+    "Should have selected the right local dir."
+  );
+  Assert.ok(profile, "A named profile matches this.");
+  Assert.equal(profile.name, "Profile1", "The right profile was matched.");
+
+  let service = getProfileService();
+  Assert.notEqual(
+    service.defaultProfile,
+    profile,
+    "Should not be the default profile."
+  );
+});
diff --git a/toolkit/profile/xpcshell/test_select_missing.js b/toolkit/profile/xpcshell/test_select_missing.js
new file mode 100644
index 0000000000..97da6d76b3
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_select_missing.js
@@ -0,0 +1,34 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that when choosing an unknown profile the profile manager is shown.
+ */
+
+add_task(async () => {
+  let profileData = {
+    options: {
+      startWithLastProfile: true,
+    },
+    profiles: [
+      {
+        name: "Profile1",
+        path: "Path1",
+      },
+      {
+        name: "Profile2",
+        path: "Path2",
+        default: true,
+      },
+      {
+        name: "Profile3",
+        path: "Path3",
+      },
+    ],
+  };
+
+  writeProfilesIni(profileData);
+  checkProfileService(profileData);
+
+  testStartsProfileManager(["-P", "foo"]);
+});
diff --git a/toolkit/profile/xpcshell/test_select_named.js b/toolkit/profile/xpcshell/test_select_named.js
new file mode 100644
index 0000000000..abecba1f4d
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_select_named.js
@@ -0,0 +1,43 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that from a database of profiles the correct profile is selected.
+ */
+
+add_task(async () => {
+  let profileData = {
+    options: {
+      startWithLastProfile: true,
+    },
+    profiles: [
+      {
+        name: "Profile1",
+        path: "Path1",
+      },
+      {
+        name: "Profile2",
+        path: "Path2",
+        default: true,
+      },
+      {
+        name: "Profile3",
+        path: "Path3",
+      },
+    ],
+  };
+
+  writeProfilesIni(profileData);
+
+  checkProfileService(profileData);
+
+  let { profile, didCreate } = selectStartupProfile(["-P", "Profile1"]);
+  checkStartupReason("argument-p");
+
+  Assert.ok(!didCreate, "Should not have created a new profile.");
+  Assert.equal(
+    profile.name,
+    "Profile1",
+    "Should have chosen the right profile"
+  );
+});
diff --git a/toolkit/profile/xpcshell/test_select_noname.js b/toolkit/profile/xpcshell/test_select_noname.js
new file mode 100644
index 0000000000..278b38089c
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_select_noname.js
@@ -0,0 +1,35 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that when passing the -P command line argument and not passing a
+ * profile name the profile manager is opened.
+ */
+
+add_task(async () => {
+  let profileData = {
+    options: {
+      startWithLastProfile: true,
+    },
+    profiles: [
+      {
+        name: "Profile1",
+        path: "Path1",
+      },
+      {
+        name: "Profile2",
+        path: "Path2",
+        default: true,
+      },
+      {
+        name: "Profile3",
+        path: "Path3",
+      },
+    ],
+  };
+
+  writeProfilesIni(profileData);
+  checkProfileService(profileData);
+
+  testStartsProfileManager(["-P"]);
+});
diff --git a/toolkit/profile/xpcshell/test_select_profile_argument.js b/toolkit/profile/xpcshell/test_select_profile_argument.js
new file mode 100644
index 0000000000..70be506538
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_select_profile_argument.js
@@ -0,0 +1,50 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that selecting a profile directory with the "profile" argument finds
+ * the matching profile.
+ */
+
+add_task(async () => {
+  let root = makeRandomProfileDir("foo");
+  let local = gDataHomeLocal.clone();
+  local.append("foo");
+
+  let profileData = {
+    options: {
+      startWithLastProfile: true,
+    },
+    profiles: [
+      {
+        name: "Profile1",
+        path: root.leafName,
+      },
+    ],
+  };
+
+  writeProfilesIni(profileData);
+  checkProfileService(profileData);
+
+  let { rootDir, localDir, profile, didCreate } = selectStartupProfile([
+    "-profile",
+    root.path,
+  ]);
+  checkStartupReason("argument-profile");
+
+  Assert.ok(!didCreate, "Should not have created a new profile.");
+  Assert.ok(rootDir.equals(root), "Should have selected the right root dir.");
+  Assert.ok(
+    localDir.equals(local),
+    "Should have selected the right local dir."
+  );
+  Assert.ok(profile, "A named profile matches this.");
+  Assert.equal(profile.name, "Profile1", "The right profile was matched.");
+
+  let service = getProfileService();
+  Assert.notEqual(
+    service.defaultProfile,
+    profile,
+    "Should not be the default profile."
+  );
+});
diff --git a/toolkit/profile/xpcshell/test_select_profile_argument_new.js b/toolkit/profile/xpcshell/test_select_profile_argument_new.js
new file mode 100644
index 0000000000..570abbd19f
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_select_profile_argument_new.js
@@ -0,0 +1,43 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that selecting a profile directory with the "profile" argument finds
+ * doesn't match the incorrect profile.
+ */
+
+add_task(async () => {
+  let root = makeRandomProfileDir("foo");
+  let local = gDataHomeLocal.clone();
+  local.append("foo");
+  let empty = makeRandomProfileDir("empty");
+
+  let profileData = {
+    options: {
+      startWithLastProfile: true,
+    },
+    profiles: [
+      {
+        name: "Profile1",
+        path: root.leafName,
+      },
+    ],
+  };
+
+  writeProfilesIni(profileData);
+  checkProfileService(profileData);
+
+  let { rootDir, localDir, profile, didCreate } = selectStartupProfile([
+    "-profile",
+    empty.path,
+  ]);
+  checkStartupReason("argument-profile");
+
+  Assert.ok(!didCreate, "Should not have created a new profile.");
+  Assert.ok(rootDir.equals(empty), "Should have selected the right root dir.");
+  Assert.ok(
+    localDir.equals(empty),
+    "Should have selected the right local dir."
+  );
+  Assert.ok(!profile, "No named profile matches this.");
+});
diff --git a/toolkit/profile/xpcshell/test_select_profilemanager.js b/toolkit/profile/xpcshell/test_select_profilemanager.js
new file mode 100644
index 0000000000..7c8bdd820e
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_select_profilemanager.js
@@ -0,0 +1,34 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that when requested the profile manager is shown.
+ */
+
+add_task(async () => {
+  let profileData = {
+    options: {
+      startWithLastProfile: true,
+    },
+    profiles: [
+      {
+        name: "Profile1",
+        path: "Path1",
+      },
+      {
+        name: "Profile2",
+        path: "Path2",
+        default: true,
+      },
+      {
+        name: "Profile3",
+        path: "Path3",
+      },
+    ],
+  };
+
+  writeProfilesIni(profileData);
+  checkProfileService(profileData);
+
+  testStartsProfileManager(["-profilemanager"]);
+});
diff --git a/toolkit/profile/xpcshell/test_single_profile_selected.js b/toolkit/profile/xpcshell/test_single_profile_selected.js
new file mode 100644
index 0000000000..1dc1f5c872
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_single_profile_selected.js
@@ -0,0 +1,73 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Previous versions of Firefox automatically used a single profile even if it
+ * wasn't marked as the default. So we should try to upgrade that one if it was
+ * last used by this build. This test checks the case where it was.
+ */
+
+add_task(async () => {
+  let defaultProfile = makeRandomProfileDir("default");
+
+  writeCompatibilityIni(defaultProfile);
+
+  writeProfilesIni({
+    profiles: [
+      {
+        name: "default",
+        path: defaultProfile.leafName,
+        default: false,
+      },
+    ],
+  });
+
+  let { profile: selectedProfile, didCreate } = selectStartupProfile();
+  checkStartupReason("firstrun-claimed-default");
+
+  let hash = xreDirProvider.getInstallHash();
+  let profileData = readProfilesIni();
+
+  Assert.ok(
+    profileData.options.startWithLastProfile,
+    "Should be set to start with the last profile."
+  );
+  Assert.equal(
+    profileData.profiles.length,
+    1,
+    "Should have the right number of profiles."
+  );
+
+  let profile = profileData.profiles[0];
+  Assert.equal(profile.name, "default", "Should have the right name.");
+  Assert.equal(
+    profile.path,
+    defaultProfile.leafName,
+    "Should be the original default profile."
+  );
+  Assert.ok(profile.default, "Should be marked as the old-style default.");
+
+  Assert.equal(
+    Object.keys(profileData.installs).length,
+    1,
+    "Should be only one known install."
+  );
+  Assert.equal(
+    profileData.installs[hash].default,
+    defaultProfile.leafName,
+    "Should have marked the original default profile as the default for this install."
+  );
+  Assert.ok(
+    !profileData.installs[hash].locked,
+    "Should not have locked as we're not the default app."
+  );
+
+  checkProfileService(profileData);
+
+  Assert.ok(!didCreate, "Should not have created a new profile.");
+  Assert.ok(
+    selectedProfile.rootDir.equals(defaultProfile),
+    "Should be using the right directory."
+  );
+  Assert.equal(selectedProfile.name, "default");
+});
diff --git a/toolkit/profile/xpcshell/test_single_profile_unselected.js b/toolkit/profile/xpcshell/test_single_profile_unselected.js
new file mode 100644
index 0000000000..3ad36de387
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_single_profile_unselected.js
@@ -0,0 +1,74 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Previous versions of Firefox automatically used a single profile even if it
+ * wasn't marked as the default. So we should try to upgrade that one if it was
+ * last used by this build. This test checks the case where it wasn't.
+ */
+
+add_task(async () => {
+  let defaultProfile = makeRandomProfileDir("default");
+
+  // Just pretend this profile was last used by something in the profile dir.
+  let greDir = gProfD.clone();
+  greDir.append("app");
+  writeCompatibilityIni(defaultProfile, greDir, greDir);
+
+  writeProfilesIni({
+    profiles: [
+      {
+        name: "default",
+        path: defaultProfile.leafName,
+        default: false,
+      },
+    ],
+  });
+
+  let profileData = readProfilesIni();
+
+  Assert.ok(
+    profileData.options.startWithLastProfile,
+    "Should be set to start with the last profile."
+  );
+  Assert.equal(
+    profileData.profiles.length,
+    1,
+    "Should have the right number of profiles."
+  );
+
+  let profile = profileData.profiles[0];
+  Assert.equal(profile.name, "default", "Should have the right name.");
+  Assert.equal(
+    profile.path,
+    defaultProfile.leafName,
+    "Should be the original default profile."
+  );
+  Assert.ok(!profile.default, "Should not be marked as the old-style default.");
+
+  Assert.ok(!profileData.installs, "Should be no defaults for installs yet.");
+
+  checkProfileService(profileData);
+
+  let { profile: selectedProfile, didCreate } = selectStartupProfile();
+  checkStartupReason("firstrun-skipped-default");
+  Assert.ok(didCreate, "Should have created a new profile.");
+  Assert.ok(
+    !selectedProfile.rootDir.equals(defaultProfile),
+    "Should be using the right directory."
+  );
+  Assert.equal(selectedProfile.name, DEDICATED_NAME);
+
+  profileData = readProfilesIni();
+
+  profile = profileData.profiles[0];
+  Assert.equal(profile.name, "default", "Should have the right name.");
+  Assert.equal(
+    profile.path,
+    defaultProfile.leafName,
+    "Should be the original default profile."
+  );
+  Assert.ok(profile.default, "Should now be marked as the old-style default.");
+
+  checkProfileService(profileData);
+});
diff --git a/toolkit/profile/xpcshell/test_skip_locked_environment.js b/toolkit/profile/xpcshell/test_skip_locked_environment.js
new file mode 100644
index 0000000000..f98f6dd88f
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_skip_locked_environment.js
@@ -0,0 +1,131 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that the environment variables are used to select a profile and that
+ * on the first run of a dedicated profile build we don't snatch it if it is
+ * locked by another install.
+ */
+
+add_task(async () => {
+  let root = makeRandomProfileDir("foo");
+  let local = gDataHomeLocal.clone();
+  local.append("foo");
+
+  writeCompatibilityIni(root);
+
+  let profileData = {
+    options: {
+      startWithLastProfile: true,
+    },
+    profiles: [
+      {
+        name: PROFILE_DEFAULT,
+        path: root.leafName,
+        default: true,
+      },
+      {
+        name: "Profile2",
+        path: "Path2",
+      },
+      {
+        name: "Profile3",
+        path: "Path3",
+      },
+    ],
+    // Another install is using the profile and it is locked.
+    installs: {
+      otherinstall: {
+        default: root.leafName,
+        locked: true,
+      },
+    },
+  };
+
+  writeProfilesIni(profileData);
+  checkProfileService(profileData);
+
+  Services.env.set("XRE_PROFILE_PATH", root.path);
+  Services.env.set("XRE_PROFILE_LOCAL_PATH", local.path);
+
+  let { rootDir, localDir, profile, didCreate } = selectStartupProfile();
+  checkStartupReason("restart-skipped-default");
+
+  // Since there is already a profile with the desired name on dev-edition, a
+  // unique version will be used.
+  let expectedName = AppConstants.MOZ_DEV_EDITION
+    ? `${DEDICATED_NAME}-1`
+    : DEDICATED_NAME;
+
+  Assert.ok(didCreate, "Should have created a new profile.");
+  Assert.ok(!rootDir.equals(root), "Should have selected the right root dir.");
+  Assert.ok(
+    !localDir.equals(local),
+    "Should have selected the right local dir."
+  );
+  Assert.ok(profile, "A named profile was returned.");
+  Assert.equal(profile.name, expectedName, "The right profile name was used.");
+
+  let service = getProfileService();
+  Assert.equal(
+    service.defaultProfile,
+    profile,
+    "Should be the default profile."
+  );
+  Assert.equal(
+    service.currentProfile,
+    profile,
+    "Should be the current profile."
+  );
+
+  profileData = readProfilesIni();
+
+  Assert.equal(
+    profileData.profiles[0].name,
+    PROFILE_DEFAULT,
+    "Should be the right profile."
+  );
+  Assert.ok(
+    profileData.profiles[0].default,
+    "Should be the old default profile."
+  );
+  Assert.equal(
+    profileData.profiles[0].path,
+    root.leafName,
+    "Should be the correct path."
+  );
+  Assert.equal(
+    profileData.profiles[1].name,
+    expectedName,
+    "Should be the right profile."
+  );
+  Assert.ok(
+    !profileData.profiles[1].default,
+    "Should not be the old default profile."
+  );
+
+  let hash = xreDirProvider.getInstallHash();
+  Assert.equal(
+    Object.keys(profileData.installs).length,
+    2,
+    "Should be one known install."
+  );
+  Assert.notEqual(
+    profileData.installs[hash].default,
+    root.leafName,
+    "Should have marked the original default profile as the default for this install."
+  );
+  Assert.ok(
+    profileData.installs[hash].locked,
+    "Should have locked as we created the profile for this install."
+  );
+  Assert.equal(
+    profileData.installs.otherinstall.default,
+    root.leafName,
+    "Should have left the other profile as the default for the other install."
+  );
+  Assert.ok(
+    profileData.installs[hash].locked,
+    "Should still be locked to the other install."
+  );
+});
diff --git a/toolkit/profile/xpcshell/test_snap.js b/toolkit/profile/xpcshell/test_snap.js
new file mode 100644
index 0000000000..c29c85089e
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_snap.js
@@ -0,0 +1,65 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that an old-style default profile not previously used by this build gets
+ * used in a snap environment.
+ */
+
+add_task(async () => {
+  let defaultProfile = makeRandomProfileDir("default");
+
+  // Just pretend this profile was last used by something in the profile dir.
+  let greDir = gProfD.clone();
+  greDir.append("app");
+  writeCompatibilityIni(defaultProfile, greDir, greDir);
+
+  writeProfilesIni({
+    profiles: [
+      {
+        name: PROFILE_DEFAULT,
+        path: defaultProfile.leafName,
+        default: true,
+      },
+    ],
+  });
+
+  let { profile: selectedProfile, didCreate } = selectStartupProfile();
+  checkStartupReason("default");
+
+  let profileData = readProfilesIni();
+  let installsINI = gDataHome.clone();
+  installsINI.append("installs.ini");
+  Assert.ok(
+    !installsINI.exists(),
+    "Installs database should not have been created."
+  );
+
+  Assert.ok(
+    profileData.options.startWithLastProfile,
+    "Should be set to start with the last profile."
+  );
+  Assert.equal(
+    profileData.profiles.length,
+    1,
+    "Should have the right number of profiles."
+  );
+
+  let profile = profileData.profiles[0];
+  Assert.equal(profile.name, PROFILE_DEFAULT, "Should have the right name.");
+  Assert.equal(
+    profile.path,
+    defaultProfile.leafName,
+    "Should be the original default profile."
+  );
+  Assert.ok(profile.default, "Should be marked as the old-style default.");
+
+  checkProfileService(profileData);
+
+  Assert.ok(!didCreate, "Should not have created a new profile.");
+  Assert.ok(
+    selectedProfile.rootDir.equals(defaultProfile),
+    "Should be using the right directory."
+  );
+  Assert.equal(selectedProfile.name, PROFILE_DEFAULT);
+});
diff --git a/toolkit/profile/xpcshell/test_snap_empty.js b/toolkit/profile/xpcshell/test_snap_empty.js
new file mode 100644
index 0000000000..80b1de9569
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_snap_empty.js
@@ -0,0 +1,26 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that from a clean slate snap builds create an appropriate profile.
+ */
+
+add_task(async () => {
+  let service = getProfileService();
+  let { profile, didCreate } = selectStartupProfile();
+  checkStartupReason("firstrun-created-default");
+
+  Assert.ok(didCreate, "Should have created a new profile.");
+  Assert.equal(
+    profile.name,
+    PROFILE_DEFAULT,
+    "Should have used the normal name."
+  );
+  if (AppConstants.MOZ_DEV_EDITION) {
+    Assert.equal(service.profileCount, 2, "Should be two profiles.");
+  } else {
+    Assert.equal(service.profileCount, 1, "Should be only one profile.");
+  }
+
+  checkProfileService();
+});
diff --git a/toolkit/profile/xpcshell/test_snatch_environment.js b/toolkit/profile/xpcshell/test_snatch_environment.js
new file mode 100644
index 0000000000..2241fb691c
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_snatch_environment.js
@@ -0,0 +1,101 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that the environment variables are used to select a profile and that
+ * on the first run of a dedicated profile build we snatch it if it was the
+ * default profile.
+ */
+
+add_task(async () => {
+  let root = makeRandomProfileDir("foo");
+  let local = gDataHomeLocal.clone();
+  local.append("foo");
+
+  writeCompatibilityIni(root);
+
+  let profileData = {
+    options: {
+      startWithLastProfile: true,
+    },
+    profiles: [
+      {
+        name: PROFILE_DEFAULT,
+        path: root.leafName,
+        default: true,
+      },
+      {
+        name: "Profile2",
+        path: "Path2",
+      },
+      {
+        name: "Profile3",
+        path: "Path3",
+      },
+    ],
+    // Another install is using the profile but it isn't locked.
+    installs: {
+      otherinstall: {
+        default: root.leafName,
+      },
+    },
+  };
+
+  writeProfilesIni(profileData);
+  checkProfileService(profileData);
+
+  Services.env.set("XRE_PROFILE_PATH", root.path);
+  Services.env.set("XRE_PROFILE_LOCAL_PATH", local.path);
+
+  let { rootDir, localDir, profile, didCreate } = selectStartupProfile();
+  checkStartupReason("restart-claimed-default");
+
+  Assert.ok(!didCreate, "Should not have created a new profile.");
+  Assert.ok(rootDir.equals(root), "Should have selected the right root dir.");
+  Assert.ok(
+    localDir.equals(local),
+    "Should have selected the right local dir."
+  );
+  Assert.ok(profile, "A named profile matches this.");
+  Assert.equal(profile.name, PROFILE_DEFAULT, "The right profile was matched.");
+
+  let service = getProfileService();
+  Assert.equal(
+    service.defaultProfile,
+    profile,
+    "Should be the default profile."
+  );
+  Assert.equal(
+    service.currentProfile,
+    profile,
+    "Should be the current profile."
+  );
+
+  profileData = readProfilesIni();
+  Assert.equal(
+    profileData.profiles[0].name,
+    PROFILE_DEFAULT,
+    "Should be the right profile."
+  );
+  Assert.ok(
+    profileData.profiles[0].default,
+    "Should still be the old default profile."
+  );
+
+  let hash = xreDirProvider.getInstallHash();
+  // The info about the other install will have been removed so it goes through first run on next startup.
+  Assert.equal(
+    Object.keys(profileData.installs).length,
+    1,
+    "Should be one known install."
+  );
+  Assert.equal(
+    profileData.installs[hash].default,
+    root.leafName,
+    "Should have marked the original default profile as the default for this install."
+  );
+  Assert.ok(
+    !profileData.installs[hash].locked,
+    "Should not have locked as we're not the default app."
+  );
+});
diff --git a/toolkit/profile/xpcshell/test_snatch_environment_default.js b/toolkit/profile/xpcshell/test_snatch_environment_default.js
new file mode 100644
index 0000000000..d93a0cfc12
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_snatch_environment_default.js
@@ -0,0 +1,101 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that the environment variables are used to select a profile and that
+ * on the first run of a dedicated profile build we snatch it if it was the
+ * default profile and lock it when we're the default app.
+ */
+
+add_task(async () => {
+  gIsDefaultApp = true;
+
+  let root = makeRandomProfileDir("foo");
+  let local = gDataHomeLocal.clone();
+  local.append("foo");
+
+  writeCompatibilityIni(root);
+
+  let profileData = {
+    options: {
+      startWithLastProfile: true,
+    },
+    profiles: [
+      {
+        name: PROFILE_DEFAULT,
+        path: root.leafName,
+        default: true,
+      },
+      {
+        name: "Profile2",
+        path: "Path2",
+      },
+      {
+        name: "Profile3",
+        path: "Path3",
+      },
+    ],
+    // Another install is using the profile but it isn't locked.
+    installs: {
+      otherinstall: {
+        default: root.leafName,
+      },
+    },
+  };
+
+  writeProfilesIni(profileData);
+  checkProfileService(profileData);
+
+  Services.env.set("XRE_PROFILE_PATH", root.path);
+  Services.env.set("XRE_PROFILE_LOCAL_PATH", local.path);
+
+  let { rootDir, localDir, profile, didCreate } = selectStartupProfile();
+  checkStartupReason("restart-claimed-default");
+
+  Assert.ok(!didCreate, "Should not have created a new profile.");
+  Assert.ok(rootDir.equals(root), "Should have selected the right root dir.");
+  Assert.ok(
+    localDir.equals(local),
+    "Should have selected the right local dir."
+  );
+  Assert.ok(!!profile, "A named profile matches this.");
+  Assert.equal(profile.name, PROFILE_DEFAULT, "The right profile was matched.");
+
+  let service = getProfileService();
+  Assert.ok(
+    service.defaultProfile === profile,
+    "Should be the default profile."
+  );
+  Assert.ok(
+    service.currentProfile === profile,
+    "Should be the current profile."
+  );
+
+  profileData = readProfilesIni();
+  Assert.equal(
+    profileData.profiles[0].name,
+    PROFILE_DEFAULT,
+    "Should be the right profile."
+  );
+  Assert.ok(
+    profileData.profiles[0].default,
+    "Should still be the old default profile."
+  );
+
+  let hash = xreDirProvider.getInstallHash();
+  // The info about the other install will have been removed so it goes through first run on next startup.
+  Assert.equal(
+    Object.keys(profileData.installs).length,
+    1,
+    "Should be one known install."
+  );
+  Assert.equal(
+    profileData.installs[hash].default,
+    root.leafName,
+    "Should have marked the original default profile as the default for this install."
+  );
+  Assert.ok(
+    profileData.installs[hash].locked,
+    "Should have locked as we're the default app."
+  );
+});
diff --git a/toolkit/profile/xpcshell/test_startswithlast.js b/toolkit/profile/xpcshell/test_startswithlast.js
new file mode 100644
index 0000000000..1b1fef4415
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_startswithlast.js
@@ -0,0 +1,28 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that if profiles.ini is set to not start with the last profile then
+ * we show the profile manager in preference to assigning the old default.
+ */
+
+add_task(async () => {
+  let defaultProfile = makeRandomProfileDir("default");
+
+  writeCompatibilityIni(defaultProfile);
+
+  writeProfilesIni({
+    options: {
+      startWithLastProfile: false,
+    },
+    profiles: [
+      {
+        name: PROFILE_DEFAULT,
+        path: defaultProfile.leafName,
+        default: true,
+      },
+    ],
+  });
+
+  testStartsProfileManager();
+});
diff --git a/toolkit/profile/xpcshell/test_steal_inuse.js b/toolkit/profile/xpcshell/test_steal_inuse.js
new file mode 100644
index 0000000000..68263ceae1
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_steal_inuse.js
@@ -0,0 +1,77 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that an old-style default profile previously used by this build but
+ * that has already been claimed by a different build gets stolen by this build.
+ */
+
+add_task(async () => {
+  let defaultProfile = makeRandomProfileDir("default");
+
+  writeCompatibilityIni(defaultProfile);
+
+  writeProfilesIni({
+    profiles: [
+      {
+        name: PROFILE_DEFAULT,
+        path: defaultProfile.leafName,
+        default: true,
+      },
+    ],
+    installs: {
+      otherhash: {
+        default: defaultProfile.leafName,
+      },
+    },
+  });
+
+  let { profile: selectedProfile, didCreate } = selectStartupProfile();
+  checkStartupReason("firstrun-claimed-default");
+
+  let hash = xreDirProvider.getInstallHash();
+  let profileData = readProfilesIni();
+
+  Assert.ok(
+    profileData.options.startWithLastProfile,
+    "Should be set to start with the last profile."
+  );
+  Assert.equal(
+    profileData.profiles.length,
+    1,
+    "Should have the right number of profiles."
+  );
+
+  let profile = profileData.profiles[0];
+  Assert.equal(profile.name, PROFILE_DEFAULT, "Should have the right name.");
+  Assert.equal(
+    profile.path,
+    defaultProfile.leafName,
+    "Should be the original default profile."
+  );
+  Assert.ok(profile.default, "Should be marked as the old-style default.");
+
+  Assert.equal(
+    Object.keys(profileData.installs).length,
+    1,
+    "Should only be one known installs."
+  );
+  Assert.equal(
+    profileData.installs[hash].default,
+    defaultProfile.leafName,
+    "Should have taken the original default profile as the default for the current install."
+  );
+  Assert.ok(
+    !profileData.installs[hash].locked,
+    "Should not have locked as we're not the default app."
+  );
+
+  checkProfileService(profileData);
+
+  Assert.ok(!didCreate, "Should not have created a new profile.");
+  Assert.ok(
+    selectedProfile.rootDir.equals(defaultProfile),
+    "Should be using the right directory."
+  );
+  Assert.equal(selectedProfile.name, PROFILE_DEFAULT);
+});
diff --git a/toolkit/profile/xpcshell/test_update_selected_dedicated.js b/toolkit/profile/xpcshell/test_update_selected_dedicated.js
new file mode 100644
index 0000000000..5a7c734e90
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_update_selected_dedicated.js
@@ -0,0 +1,80 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that an old-style default profile previously used by this build gets
+ * updated to a dedicated profile for this build.
+ */
+
+add_task(async () => {
+  let defaultProfile = makeRandomProfileDir("default");
+
+  writeCompatibilityIni(defaultProfile);
+
+  writeProfilesIni({
+    profiles: [
+      {
+        name: PROFILE_DEFAULT,
+        path: defaultProfile.leafName,
+        default: true,
+      },
+    ],
+  });
+
+  let { profile: selectedProfile, didCreate } = selectStartupProfile();
+  checkStartupReason("firstrun-claimed-default");
+
+  let { databaseVersion, profileCount } = getTelemetryScalars();
+  Assert.equal(
+    databaseVersion,
+    "1",
+    "Old database file was present at startup."
+  );
+  Assert.equal(profileCount, 1, "Should be one profile.");
+
+  let hash = xreDirProvider.getInstallHash();
+  let profileData = readProfilesIni();
+
+  Assert.ok(
+    profileData.options.startWithLastProfile,
+    "Should be set to start with the last profile."
+  );
+  Assert.equal(
+    profileData.profiles.length,
+    1,
+    "Should have the right number of profiles."
+  );
+
+  let profile = profileData.profiles[0];
+  Assert.equal(profile.name, PROFILE_DEFAULT, "Should have the right name.");
+  Assert.equal(
+    profile.path,
+    defaultProfile.leafName,
+    "Should be the original default profile."
+  );
+  Assert.ok(profile.default, "Should be marked as the old-style default.");
+
+  Assert.equal(
+    Object.keys(profileData.installs).length,
+    1,
+    "Should be only one known install."
+  );
+  Assert.equal(
+    profileData.installs[hash].default,
+    defaultProfile.leafName,
+    "Should have marked the original default profile as the default for this install."
+  );
+  Assert.ok(
+    !profileData.installs[hash].locked,
+    "Should not have locked as we're not the default app."
+  );
+
+  checkProfileService(profileData);
+
+  Assert.ok(!didCreate, "Should not have created a new profile.");
+  Assert.ok(
+    selectedProfile.rootDir.equals(defaultProfile),
+    "Should be using the right directory."
+  );
+  Assert.equal(selectedProfile.name, PROFILE_DEFAULT);
+});
diff --git a/toolkit/profile/xpcshell/test_update_unknown_dedicated.js b/toolkit/profile/xpcshell/test_update_unknown_dedicated.js
new file mode 100644
index 0000000000..1fd8c30fbf
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_update_unknown_dedicated.js
@@ -0,0 +1,85 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that an old-style default profile not previously used by any build
+ * doesn't get updated to a dedicated profile for this build and we don't set
+ * the flag to show the user info about dedicated profiles.
+ */
+
+add_task(async () => {
+  let hash = xreDirProvider.getInstallHash();
+  let defaultProfile = makeRandomProfileDir("default");
+
+  writeProfilesIni({
+    profiles: [
+      {
+        name: PROFILE_DEFAULT,
+        path: defaultProfile.leafName,
+        default: true,
+      },
+    ],
+  });
+
+  let { profile: selectedProfile, didCreate } = selectStartupProfile();
+  checkStartupReason("firstrun-created-default");
+
+  let profileData = readProfilesIni();
+
+  Assert.ok(
+    profileData.options.startWithLastProfile,
+    "Should be set to start with the last profile."
+  );
+  Assert.equal(
+    profileData.profiles.length,
+    2,
+    "Should have the right number of profiles."
+  );
+
+  // Since there is already a profile with the desired name on dev-edition, a
+  // unique version will be used.
+  let expectedName = AppConstants.MOZ_DEV_EDITION
+    ? `${DEDICATED_NAME}-1`
+    : DEDICATED_NAME;
+
+  let profile = profileData.profiles[0];
+  Assert.equal(profile.name, PROFILE_DEFAULT, "Should have the right name.");
+  Assert.equal(
+    profile.path,
+    defaultProfile.leafName,
+    "Should be the original default profile."
+  );
+  Assert.ok(profile.default, "Should be marked as the old-style default.");
+  profile = profileData.profiles[1];
+  Assert.equal(profile.name, expectedName, "Should have the right name.");
+  Assert.notEqual(
+    profile.path,
+    defaultProfile.leafName,
+    "Should not be the original default profile."
+  );
+  Assert.ok(!profile.default, "Should not be marked as the old-style default.");
+
+  Assert.equal(
+    Object.keys(profileData.installs).length,
+    1,
+    "Should be a default for installs."
+  );
+  Assert.equal(
+    profileData.installs[hash].default,
+    profile.path,
+    "Should have the right default profile."
+  );
+  Assert.ok(
+    profileData.installs[hash].locked,
+    "Should have locked as we created this profile for this install."
+  );
+
+  checkProfileService(profileData);
+
+  Assert.ok(didCreate, "Should have created a new profile.");
+  Assert.ok(
+    !selectedProfile.rootDir.equals(defaultProfile),
+    "Should not be using the old directory."
+  );
+  Assert.equal(selectedProfile.name, expectedName);
+});
diff --git a/toolkit/profile/xpcshell/test_update_unselected_dedicated.js b/toolkit/profile/xpcshell/test_update_unselected_dedicated.js
new file mode 100644
index 0000000000..4aa56eaaac
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_update_unselected_dedicated.js
@@ -0,0 +1,89 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/*
+ * Tests that an old-style default profile not previously used by this build gets
+ * ignored.
+ */
+
+add_task(async () => {
+  let hash = xreDirProvider.getInstallHash();
+  let defaultProfile = makeRandomProfileDir("default");
+
+  // Just pretend this profile was last used by something in the profile dir.
+  let greDir = gProfD.clone();
+  greDir.append("app");
+  writeCompatibilityIni(defaultProfile, greDir, greDir);
+
+  writeProfilesIni({
+    profiles: [
+      {
+        name: PROFILE_DEFAULT,
+        path: defaultProfile.leafName,
+        default: true,
+      },
+    ],
+  });
+
+  let { profile: selectedProfile, didCreate } = selectStartupProfile();
+  checkStartupReason("firstrun-skipped-default");
+
+  let profileData = readProfilesIni();
+
+  Assert.ok(
+    profileData.options.startWithLastProfile,
+    "Should be set to start with the last profile."
+  );
+  Assert.equal(
+    profileData.profiles.length,
+    2,
+    "Should have the right number of profiles."
+  );
+
+  // Since there is already a profile with the desired name on dev-edition, a
+  // unique version will be used.
+  let expectedName = AppConstants.MOZ_DEV_EDITION
+    ? `${DEDICATED_NAME}-1`
+    : DEDICATED_NAME;
+
+  let profile = profileData.profiles[0];
+  Assert.equal(profile.name, PROFILE_DEFAULT, "Should have the right name.");
+  Assert.equal(
+    profile.path,
+    defaultProfile.leafName,
+    "Should be the original default profile."
+  );
+  Assert.ok(profile.default, "Should be marked as the old-style default.");
+  profile = profileData.profiles[1];
+  Assert.equal(profile.name, expectedName, "Should have the right name.");
+  Assert.notEqual(
+    profile.path,
+    defaultProfile.leafName,
+    "Should not be the original default profile."
+  );
+  Assert.ok(!profile.default, "Should not be marked as the old-style default.");
+
+  Assert.equal(
+    Object.keys(profileData.installs).length,
+    1,
+    "Should be a default for this install."
+  );
+  Assert.equal(
+    profileData.installs[hash].default,
+    profile.path,
+    "Should have marked the new profile as the default for this install."
+  );
+  Assert.ok(
+    profileData.installs[hash].locked,
+    "Should have locked as we created this profile for this install."
+  );
+
+  checkProfileService(profileData);
+
+  Assert.ok(didCreate, "Should have created a new profile.");
+  Assert.ok(
+    !selectedProfile.rootDir.equals(defaultProfile),
+    "Should be using the right directory."
+  );
+  Assert.equal(selectedProfile.name, expectedName);
+});
diff --git a/toolkit/profile/xpcshell/test_use_dedicated.js b/toolkit/profile/xpcshell/test_use_dedicated.js
new file mode 100644
index 0000000000..d83b6fc3a7
--- /dev/null
+++ b/toolkit/profile/xpcshell/test_use_dedicated.js
@@ -0,0 +1,107 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+/**
+ * Tests that if installs.ini lists a profile we use it as the default.
+ */
+
+add_task(async () => {
+  let hash = xreDirProvider.getInstallHash();
+  let defaultProfile = makeRandomProfileDir("default");
+  let dedicatedProfile = makeRandomProfileDir("dedicated");
+  let devProfile = makeRandomProfileDir("devedition");
+
+  // Make sure we don't steal the old-style default.
+  writeCompatibilityIni(defaultProfile);
+
+  writeProfilesIni({
+    profiles: [
+      {
+        name: "default",
+        path: defaultProfile.leafName,
+        default: true,
+      },
+      {
+        name: "dedicated",
+        path: dedicatedProfile.leafName,
+      },
+      {
+        name: "dev-edition-default",
+        path: devProfile.leafName,
+      },
+    ],
+    installs: {
+      [hash]: {
+        default: dedicatedProfile.leafName,
+      },
+      otherhash: {
+        default: "foobar",
+      },
+    },
+  });
+
+  let { profile: selectedProfile, didCreate } = selectStartupProfile();
+  checkStartupReason("default");
+  let { databaseVersion, profileCount } = getTelemetryScalars();
+  Assert.equal(
+    databaseVersion,
+    "2",
+    "New database file was present at startup."
+  );
+  Assert.equal(profileCount, 3, "Should be three profiles present.");
+
+  let profileData = readProfilesIni();
+
+  Assert.ok(
+    profileData.options.startWithLastProfile,
+    "Should be set to start with the last profile."
+  );
+  Assert.equal(
+    profileData.profiles.length,
+    3,
+    "Should have the right number of profiles."
+  );
+
+  let profile = profileData.profiles[0];
+  Assert.equal(profile.name, `dedicated`, "Should have the right name.");
+  Assert.equal(
+    profile.path,
+    dedicatedProfile.leafName,
+    "Should be the expected dedicated profile."
+  );
+  Assert.ok(!profile.default, "Should not be marked as the old-style default.");
+
+  profile = profileData.profiles[1];
+  Assert.equal(profile.name, "default", "Should have the right name.");
+  Assert.equal(
+    profile.path,
+    defaultProfile.leafName,
+    "Should be the original default profile."
+  );
+  Assert.ok(profile.default, "Should be marked as the old-style default.");
+
+  Assert.equal(
+    Object.keys(profileData.installs).length,
+    2,
+    "Should be two known installs."
+  );
+  Assert.equal(
+    profileData.installs[hash].default,
+    dedicatedProfile.leafName,
+    "Should have kept the default for this install."
+  );
+  Assert.equal(
+    profileData.installs.otherhash.default,
+    "foobar",
+    "Should have kept the default for the other install."
+  );
+
+  checkProfileService(profileData);
+
+  Assert.ok(!didCreate, "Should not have created a new profile.");
+  Assert.ok(
+    selectedProfile.rootDir.equals(dedicatedProfile),
+    "Should be using the right directory."
+  );
+  Assert.equal(selectedProfile.name, "dedicated");
+});
diff --git a/toolkit/profile/xpcshell/xpcshell.toml b/toolkit/profile/xpcshell/xpcshell.toml
new file mode 100644
index 0000000000..00c00cc6c4
--- /dev/null
+++ b/toolkit/profile/xpcshell/xpcshell.toml
@@ -0,0 +1,97 @@
+[DEFAULT]
+head = "head.js"
+skip-if = ["os == 'android'"]
+
+["test_check_backup.js"]
+
+["test_claim_locked.js"]
+
+["test_clean.js"]
+
+["test_conflict_installs.js"]
+
+["test_conflict_profiles.js"]
+
+["test_create_default.js"]
+
+["test_fix_directory_case.js"]
+
+["test_ignore_legacy_directory.js"]
+
+["test_invalid_descriptor.js"]
+
+["test_legacy_empty.js"]
+
+["test_legacy_select.js"]
+
+["test_lock.js"]
+
+["test_missing_profilesini.js"]
+
+["test_new_default.js"]
+
+["test_previous_dedicated.js"]
+
+["test_profile_reset.js"]
+
+["test_remove.js"]
+
+["test_remove_default.js"]
+
+["test_select_backgroundtasks_ephemeral.js"]
+
+["test_select_backgroundtasks_not_ephemeral_create.js"]
+
+["test_select_backgroundtasks_not_ephemeral_exists.js"]
+
+["test_select_default.js"]
+
+["test_select_environment.js"]
+
+["test_select_environment_named.js"]
+
+["test_select_missing.js"]
+
+["test_select_named.js"]
+
+["test_select_noname.js"]
+
+["test_select_profile_argument.js"]
+
+["test_select_profile_argument_new.js"]
+
+["test_select_profilemanager.js"]
+
+["test_single_profile_selected.js"]
+skip-if = ["devedition"]
+
+["test_single_profile_unselected.js"]
+skip-if = ["devedition"]
+
+["test_skip_locked_environment.js"]
+
+["test_snap.js"]
+snap = true
+run-if = ["os == 'linux'"]
+skip-if = ["appname == 'thunderbird'"]
+
+["test_snap_empty.js"]
+snap = true
+run-if = ["os == 'linux'"]
+skip-if = ["appname == 'thunderbird'"]
+
+["test_snatch_environment.js"]
+
+["test_snatch_environment_default.js"]
+
+["test_startswithlast.js"]
+
+["test_steal_inuse.js"]
+
+["test_update_selected_dedicated.js"]
+
+["test_update_unknown_dedicated.js"]
+
+["test_update_unselected_dedicated.js"]
+
+["test_use_dedicated.js"]