1 files changed, 230 insertions, 0 deletions
diff --git a/browser/modules/test/unit/test_ProfileCounter.js b/browser/modules/test/unit/test_ProfileCounter.js
new file mode 100644
index 0000000000..d2febe77a9
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+++ b/browser/modules/test/unit/test_ProfileCounter.js
@@ -0,0 +1,230 @@
+/* Any copyright is dedicated to the Public Domain.
+ * http://creativecommons.org/publicdomain/zero/1.0/
+ */
+"use strict";
+
+const { BrowserUsageTelemetry } = ChromeUtils.import(
+  "resource:///modules/BrowserUsageTelemetry.jsm"
+);
+const { TelemetryTestUtils } = ChromeUtils.importESModule(
+  "resource://testing-common/TelemetryTestUtils.sys.mjs"
+);
+
+const PROFILE_COUNT_SCALAR = "browser.engagement.profile_count";
+// Largest possible uint32_t value represents an error.
+const SCALAR_ERROR_VALUE = 0;
+
+const FILE_OPEN_OPERATION = "open";
+const ERROR_FILE_NOT_FOUND = "NotFoundError";
+const ERROR_ACCESS_DENIED = "NotAllowedError";
+
+// We will redirect I/O to/from the profile counter file to read/write this
+// variable instead. That makes it easier for us to:
+//   - avoid interference from any pre-existing file
+//   - read and change the values in the file.
+//   - clean up changes made to the file
+// We will translate a null value stored here to a File Not Found error.
+var gFakeProfileCounterFile = null;
+// We will use this to check that the profile counter code doesn't try to write
+// to multiple files (since this test will malfunction in that case due to
+// gFakeProfileCounterFile only being setup to accommodate a single file).
+var gProfileCounterFilePath = null;
+
+// Storing a value here lets us test the behavior when we encounter an error
+// reading or writing to the file. A null value means that no error will
+// be simulated (other than possibly a NotFoundError).
+var gNextReadExceptionReason = null;
+var gNextWriteExceptionReason = null;
+
+// Nothing will actually be stored in this directory, so it's not important that
+// it be valid, but the leafname should be unique to this test in order to be
+// sure of preventing name conflicts with the pref:
+// `browser.engagement.profileCounted.${hash}`
+function getDummyUpdateDirectory() {
+  const testName = "test_ProfileCounter";
+  let dir = Cc["@mozilla.org/file/local;1"].createInstance(Ci.nsIFile);
+  dir.initWithPath(`C:\\foo\\bar\\${testName}`);
+  return dir;
+}
+
+// We aren't going to bother generating anything looking like a real client ID
+// for this. The only real requirements for client ids is that they not repeat
+// and that they be strings. So we'll just return an integer as a string and
+// increment it when we want a new client id.
+var gDummyTelemetryClientId = 0;
+function getDummyTelemetryClientId() {
+  return gDummyTelemetryClientId.toString();
+}
+function setNewDummyTelemetryClientId() {
+  ++gDummyTelemetryClientId;
+}
+
+// Returns null if the (fake) profile count file hasn't been created yet.
+function getProfileCount() {
+  // Strict equality to ensure distinguish properly between a non-existent
+  // file and an empty one.
+  if (gFakeProfileCounterFile === null) {
+    return null;
+  }
+  let saveData = JSON.parse(gFakeProfileCounterFile);
+  return saveData.profileTelemetryIds.length;
+}
+
+// Resets the state to the original state, before the profile count file has
+// even been written.
+// If resetFile is specified as false, this will reset everything except for the
+// file itself. This allows us to sort of pretend that another installation
+// wrote the file.
+function reset(resetFile = true) {
+  if (resetFile) {
+    gFakeProfileCounterFile = null;
+  }
+  gNextReadExceptionReason = null;
+  gNextWriteExceptionReason = null;
+  setNewDummyTelemetryClientId();
+}
+
+function setup() {
+  reset();
+
+  BrowserUsageTelemetry.Policy.readProfileCountFile = async path => {
+    if (!gProfileCounterFilePath) {
+      gProfileCounterFilePath = path;
+    } else {
+      // We've only got one mock-file variable. Make sure we are always
+      // accessing the same file or this will cause problems.
+      Assert.equal(
+        gProfileCounterFilePath,
+        path,
+        "Only one file should be accessed"
+      );
+    }
+    // Strict equality to ensure distinguish properly between null and 0.
+    if (gNextReadExceptionReason !== null) {
+      let ex = new DOMException(FILE_OPEN_OPERATION, gNextReadExceptionReason);
+      gNextReadExceptionReason = null;
+      throw ex;
+    }
+    // Strict equality to ensure distinguish properly between a non-existent
+    // file and an empty one.
+    if (gFakeProfileCounterFile === null) {
+      throw new DOMException(FILE_OPEN_OPERATION, ERROR_FILE_NOT_FOUND);
+    }
+    return gFakeProfileCounterFile;
+  };
+  BrowserUsageTelemetry.Policy.writeProfileCountFile = async (path, data) => {
+    if (!gProfileCounterFilePath) {
+      gProfileCounterFilePath = path;
+    } else {
+      // We've only got one mock-file variable. Make sure we are always
+      // accessing the same file or this will cause problems.
+      Assert.equal(
+        gProfileCounterFilePath,
+        path,
+        "Only one file should be accessed"
+      );
+    }
+    // Strict equality to ensure distinguish properly between null and 0.
+    if (gNextWriteExceptionReason !== null) {
+      let ex = new DOMException(FILE_OPEN_OPERATION, gNextWriteExceptionReason);
+      gNextWriteExceptionReason = null;
+      throw ex;
+    }
+    gFakeProfileCounterFile = data;
+  };
+  BrowserUsageTelemetry.Policy.getUpdateDirectory = getDummyUpdateDirectory;
+  BrowserUsageTelemetry.Policy.getTelemetryClientId = getDummyTelemetryClientId;
+}
+
+// Checks that the number of profiles reported is the number expected. Because
+// of bucketing, the raw count may be different than the reported count.
+function checkSuccess(profilesReported, rawCount = profilesReported) {
+  Assert.equal(rawCount, getProfileCount());
+  const scalars = TelemetryTestUtils.getProcessScalars("parent");
+  TelemetryTestUtils.assertScalar(
+    scalars,
+    PROFILE_COUNT_SCALAR,
+    profilesReported,
+    "The value reported to telemetry should be the expected profile count"
+  );
+}
+
+function checkError() {
+  const scalars = TelemetryTestUtils.getProcessScalars("parent");
+  TelemetryTestUtils.assertScalar(
+    scalars,
+    PROFILE_COUNT_SCALAR,
+    SCALAR_ERROR_VALUE,
+    "The value reported to telemetry should be the error value"
+  );
+}
+
+add_task(async function testProfileCounter() {
+  setup();
+
+  info("Testing basic functionality, single install");
+  await BrowserUsageTelemetry.reportProfileCount();
+  checkSuccess(1);
+  await BrowserUsageTelemetry.reportProfileCount();
+  checkSuccess(1);
+
+  // Fake another installation by resetting everything except for the profile
+  // count file.
+  reset(false);
+
+  info("Testing basic functionality, faking a second install");
+  await BrowserUsageTelemetry.reportProfileCount();
+  checkSuccess(2);
+
+  // Check if we properly handle the case where we cannot read from the file
+  // and we have already set its contents. This should report an error.
+  info("Testing read error after successful write");
+  gNextReadExceptionReason = ERROR_ACCESS_DENIED;
+  await BrowserUsageTelemetry.reportProfileCount();
+  checkError();
+
+  reset();
+
+  // A read error should cause an error to be reported, but should also write
+  // to the file in an attempt to fix it. So the next (successful) read should
+  // result in the correct telemetry.
+  info("Testing read error self-correction");
+  gNextReadExceptionReason = ERROR_ACCESS_DENIED;
+  await BrowserUsageTelemetry.reportProfileCount();
+  checkError();
+
+  await BrowserUsageTelemetry.reportProfileCount();
+  checkSuccess(1);
+
+  reset();
+
+  // If the file is malformed. We should report an error and fix it, then report
+  // the correct profile count next time.
+  info("Testing with malformed profile count file");
+  gFakeProfileCounterFile = "<malformed file data>";
+  await BrowserUsageTelemetry.reportProfileCount();
+  checkError();
+
+  await BrowserUsageTelemetry.reportProfileCount();
+  checkSuccess(1);
+
+  reset();
+
+  // If we haven't yet written to the file, a write error should cause an error
+  // to be reported.
+  info("Testing write error before the first write");
+  gNextWriteExceptionReason = ERROR_ACCESS_DENIED;
+  await BrowserUsageTelemetry.reportProfileCount();
+  checkError();
+
+  reset();
+
+  info("Testing bucketing");
+  // Fake 15 installations to drive the raw profile count up to 15.
+  for (let i = 0; i < 15; i++) {
+    reset(false);
+    await BrowserUsageTelemetry.reportProfileCount();
+  }
+  // With bucketing, values from 10-99 should all be reported as 10.
+  checkSuccess(10, 15);
+});