1 files changed, 33 insertions, 0 deletions
diff --git a/devtools/client/shared/sourceeditor/test/browser_codemirror.js b/devtools/client/shared/sourceeditor/test/browser_codemirror.js
new file mode 100644
index 0000000000..ca19c20d9f
--- /dev/null
+++ b/devtools/client/shared/sourceeditor/test/browser_codemirror.js
@@ -0,0 +1,33 @@
+/* Any copyright is dedicated to the Public Domain.
+   http://creativecommons.org/publicdomain/zero/1.0/ */
+
+"use strict";
+
+const URI =
+  "chrome://mochitests/content/browser/devtools/client/shared/sourceeditor/" +
+  "test/codemirror/codemirror.html";
+
+add_task(async function test() {
+  requestLongerTimeout(3);
+
+  /*
+   * In devtools/client/shared/sourceeditor/test/codemirror/search_test.js there is a test
+   * multilineInsensitiveSlow which assumes an operation takes less than 100ms.
+   * With a precision of 100ms, if we get unlikely and begin execution towards the
+   * end of one spot (e.g. at 95 ms) we will clamp down, take (e.g.) 10ms to execute
+   * and it will appear to take 100ms.
+   *
+   * To avoid this, we hardcode to 2ms of precision.
+   *
+   * In theory we don't need to set the pref for all of CodeMirror, in practice
+   * it seems very difficult to set a pref for just one of the tests.
+   */
+  await SpecialPowers.pushPrefEnv({
+    set: [
+      ["privacy.reduceTimerPrecision", true],
+      ["privacy.resistFingerprinting.reduceTimerPrecision.microseconds", 2000],
+    ],
+  });
+
+  await runCodeMirrorTest(URI);
+});