1 files changed, 103 insertions, 0 deletions
diff --git a/dom/media/test/gUM_support.js b/dom/media/test/gUM_support.js
new file mode 100644
index 0000000000..80d218cae7
--- /dev/null
+++ b/dom/media/test/gUM_support.js
@@ -0,0 +1,103 @@
+// Support script for test that use getUserMedia. This allows explicit
+// configuration of prefs which affect gUM. See also
+// `testing/mochitest/runtests.py` for how the harness configures values.
+
+// Setup preconditions for tests using getUserMedia. This functions helps
+// manage different prefs that affect gUM calls in tests and makes explicit
+// the expected state before test runs.
+async function pushGetUserMediaTestPrefs({
+  fakeAudio = false,
+  fakeVideo = false,
+  loopbackAudio = false,
+  loopbackVideo = false,
+}) {
+  // Make sure we have sensical arguments
+  if (!fakeAudio && !loopbackAudio) {
+    throw new Error(
+      "pushGetUserMediaTestPrefs: Should have fake or loopback audio!"
+    );
+  } else if (fakeAudio && loopbackAudio) {
+    throw new Error(
+      "pushGetUserMediaTestPrefs: Should not have both fake and loopback audio!"
+    );
+  }
+  if (!fakeVideo && !loopbackVideo) {
+    throw new Error(
+      "pushGetUserMediaTestPrefs: Should have fake or loopback video!"
+    );
+  } else if (fakeVideo && loopbackVideo) {
+    throw new Error(
+      "pushGetUserMediaTestPrefs: Should not have both fake and loopback video!"
+    );
+  }
+
+  let testPrefs = [];
+  if (fakeAudio) {
+    // Unset the loopback device so it doesn't take precedence
+    testPrefs.push(["media.audio_loopback_dev", ""]);
+    // Setup fake streams pref
+    testPrefs.push(["media.navigator.streams.fake", true]);
+  }
+  if (loopbackAudio) {
+    // If audio loopback is requested we expect the test harness to have set
+    // the loopback device pref, make sure it's set
+    let audioLoopDev = SpecialPowers.getCharPref(
+      "media.audio_loopback_dev",
+      ""
+    );
+    if (!audioLoopDev) {
+      throw new Error(
+        "pushGetUserMediaTestPrefs: Loopback audio requested but " +
+          "media.audio_loopback_dev does not appear to be set!"
+      );
+    }
+  }
+  if (fakeVideo) {
+    // Unset the loopback device so it doesn't take precedence
+    testPrefs.push(["media.video_loopback_dev", ""]);
+    // Setup fake streams pref
+    testPrefs.push(["media.navigator.streams.fake", true]);
+  }
+  if (loopbackVideo) {
+    // If video loopback is requested we expect the test harness to have set
+    // the loopback device pref, make sure it's set
+    let videoLoopDev = SpecialPowers.getCharPref(
+      "media.video_loopback_dev",
+      ""
+    );
+    if (!videoLoopDev) {
+      throw new Error(
+        "pushGetUserMediaTestPrefs: Loopback video requested but " +
+          "media.video_loopback_dev does not appear to be set!"
+      );
+    }
+  }
+  // Prevent presentation of the gUM permission prompt.
+  testPrefs.push(["media.navigator.permission.disabled", true]);
+  return SpecialPowers.pushPrefEnv({ set: testPrefs });
+}
+
+// Setup preconditions for tests using getUserMedia. This function will
+// configure prefs to select loopback device(s) if it can find loopback device
+// names already set in the prefs. If no loopback device name can be found then
+// prefs are setup such that a fake device is used.
+async function setupGetUserMediaTestPrefs() {
+  let prefRequests = {};
+  let audioLoopDev = SpecialPowers.getCharPref("media.audio_loopback_dev", "");
+  if (audioLoopDev) {
+    prefRequests.fakeAudio = false;
+    prefRequests.loopbackAudio = true;
+  } else {
+    prefRequests.fakeAudio = true;
+    prefRequests.loopbackAudio = false;
+  }
+  let videoLoopDev = SpecialPowers.getCharPref("media.video_loopback_dev", "");
+  if (videoLoopDev) {
+    prefRequests.fakeVideo = false;
+    prefRequests.loopbackVideo = true;
+  } else {
+    prefRequests.fakeVideo = true;
+    prefRequests.loopbackVideo = false;
+  }
+  return pushGetUserMediaTestPrefs(prefRequests);
+}