1 files changed, 63 insertions, 0 deletions
diff --git a/toolkit/components/osfile/tests/xpcshell/test_telemetry.js b/toolkit/components/osfile/tests/xpcshell/test_telemetry.js
new file mode 100644
index 000000000..dc5104443
--- /dev/null
+++ b/toolkit/components/osfile/tests/xpcshell/test_telemetry.js
@@ -0,0 +1,63 @@
+"use strict";
+
+var {OS: {File, Path, Constants}} = Components.utils.import("resource://gre/modules/osfile.jsm", {});
+var {Services} = Components.utils.import("resource://gre/modules/Services.jsm", {});
+
+// Ensure that we have a profile but that the OS.File worker is not launched
+add_task(function* init() {
+  do_get_profile();
+  yield File.resetWorker();
+});
+
+function getCount(histogram) {
+  if (histogram == null) {
+    return 0;
+  }
+
+  let total = 0;
+  for (let i of histogram.counts) {
+    total += i;
+  }
+  return total;
+}
+
+// Ensure that launching the OS.File worker adds data to the relevant
+// histograms
+add_task(function* test_startup() {
+  let LAUNCH = "OSFILE_WORKER_LAUNCH_MS";
+  let READY = "OSFILE_WORKER_READY_MS";
+
+  let before = Services.telemetry.histogramSnapshots;
+
+  // Launch the OS.File worker
+  yield File.getCurrentDirectory();
+
+  let after = Services.telemetry.histogramSnapshots;
+
+
+  do_print("Ensuring that we have recorded measures for histograms");
+  do_check_eq(getCount(after[LAUNCH]), getCount(before[LAUNCH]) + 1);
+  do_check_eq(getCount(after[READY]), getCount(before[READY]) + 1);
+
+  do_print("Ensuring that launh <= ready");
+  do_check_true(after[LAUNCH].sum <= after[READY].sum);
+});
+
+// Ensure that calling writeAtomic adds data to the relevant histograms
+add_task(function* test_writeAtomic() {
+  let LABEL = "OSFILE_WRITEATOMIC_JANK_MS";
+
+  let before = Services.telemetry.histogramSnapshots;
+
+  // Perform a write.
+  let path = Path.join(Constants.Path.profileDir, "test_osfile_telemetry.tmp");
+  yield File.writeAtomic(path, LABEL, { tmpPath: path + ".tmp" } );
+
+  let after = Services.telemetry.histogramSnapshots;
+
+  do_check_eq(getCount(after[LABEL]), getCount(before[LABEL]) + 1);
+});
+
+function run_test() {
+  run_next_test();
+}