2 files changed, 142 insertions, 0 deletions
diff --git a/dom/media/mediasession/test/gtest/TestPositionState.cpp b/dom/media/mediasession/test/gtest/TestPositionState.cpp
new file mode 100644
index 0000000000..5fa38d0294
--- /dev/null
+++ b/dom/media/mediasession/test/gtest/TestPositionState.cpp
@@ -0,0 +1,127 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "gtest/gtest.h"
+#include "MediaSession.h"
+
+using namespace mozilla;
+using namespace mozilla::dom;
+
+struct CurrentPlaybackPositionFixture {
+  double mDuration = 0.0;
+  double mPlaybackRate = 0.0;
+  double mLastReportedTime = 0.0;
+
+  TimeDuration mDelta;
+  double mExpectedPosition = -1;
+};
+
+class CurrentPlaybackPositionTest
+    : public testing::TestWithParam<CurrentPlaybackPositionFixture> {};
+
+static const std::initializer_list<CurrentPlaybackPositionFixture> kFixtures = {
+    // position must be positive
+    {
+        10.0,
+        1.0,
+        0.0,
+        TimeDuration::FromSeconds(-1.0),
+        0.0,
+    },
+    // no time elapsed
+    {
+        10.0,
+        1.0,
+        0.0,
+        TimeDuration::FromSeconds(0.0),
+        0.0,
+    },
+    {
+        10.0,
+        1.0,
+        0.0,
+        TimeDuration::FromSeconds(3.0),
+        3.0,
+    },
+    {
+        10.0,
+        1.0,
+        0.0,
+        TimeDuration::FromSeconds(10.0),
+        10.0,
+    },
+    // position is clamped to the duration
+    {
+        10.0,
+        1.0,
+        0.0,
+        TimeDuration::FromSeconds(20.0),
+        10.0,
+    },
+    {
+        10.0,
+        1.0,
+        5.0,
+        TimeDuration::FromSeconds(-1.0),
+        4.0,
+    },
+    {
+        10.0,
+        1.0,
+        5.0,
+        TimeDuration::FromSeconds(-6.0),
+        0.0,
+    },
+    {
+        10.0,
+        1.0,
+        5.0,
+        TimeDuration::FromSeconds(6.0),
+        10.0,
+    },
+    // expected: 5s + 2 * 2s
+    {
+        10.0,
+        2.0,
+        5.0,
+        TimeDuration::FromSeconds(2.0),
+        9.0,
+    },
+    // expected: 5s + 0.5 * 2s
+    {
+        10.0,
+        0.5,
+        5.0,
+        TimeDuration::FromSeconds(2.0),
+        6.0,
+    },
+    {
+        5.0,
+        4.0,
+        10.0,
+        TimeDuration::FromSeconds(20.0),
+        5.0,
+    },
+    // empty media (0s)
+    {
+        0.0,
+        4.0,
+        5.0,
+        TimeDuration::FromSeconds(20.0),
+        0.0,
+    },
+};
+
+TEST_P(CurrentPlaybackPositionTest, Run) {
+  const auto& fixture = GetParam();
+  PositionState state(fixture.mDuration, fixture.mPlaybackRate,
+                      fixture.mLastReportedTime, TimeStamp::Now());
+
+  ASSERT_DOUBLE_EQ(state.CurrentPlaybackPosition(state.mPositionUpdatedTime +
+                                                 fixture.mDelta),
+                   fixture.mExpectedPosition);
+}
+
+INSTANTIATE_TEST_SUITE_P(PositionState, CurrentPlaybackPositionTest,
+                         testing::ValuesIn(kFixtures));
diff --git a/dom/media/mediasession/test/gtest/moz.build b/dom/media/mediasession/test/gtest/moz.build
new file mode 100644
index 0000000000..fd2a9a6e30
--- /dev/null
+++ b/dom/media/mediasession/test/gtest/moz.build
@@ -0,0 +1,15 @@
+# -*- Mode: python; indent-tabs-mode: nil; tab-width: 40 -*-
+# vim: set filetype=python:
+# This Source Code Form is subject to the terms of the Mozilla Public
+# License, v. 2.0. If a copy of the MPL was not distributed with this
+# file, You can obtain one at http://mozilla.org/MPL/2.0/.
+
+UNIFIED_SOURCES += [
+    "TestPositionState.cpp",
+]
+
+LOCAL_INCLUDES += [
+    "/dom/media/mediasession",
+]
+
+FINAL_LIBRARY = "xul-gtest"