Make Android Clipboard Keep Track of Last Modified Time

ui/android/junit/src/org/chromium/ui/base/ClipboardTest.java

Index: ui/android/junit/src/org/chromium/ui/base/ClipboardTest.java
diff --git a/ui/android/junit/src/org/chromium/ui/base/ClipboardTest.java b/ui/android/junit/src/org/chromium/ui/base/ClipboardTest.java
new file mode 100644
index 0000000000000000000000000000000000000000..e4476ba473fd47b9ddc3efb4cf63012da3f30f3c
--- /dev/null
+++ b/ui/android/junit/src/org/chromium/ui/base/ClipboardTest.java
@@ -0,0 +1,32 @@
+// Copyright 2017 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package org.chromium.ui.base;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.robolectric.annotation.Config;
+
+import org.chromium.base.test.util.AdvancedMockContext;
+import org.chromium.testing.local.LocalRobolectricTestRunner;
+
+/**
+ * Tests logic in the Clipboard class.
+ */
+@RunWith(LocalRobolectricTestRunner.class)
+@Config(manifest = Config.NONE)
+public class ClipboardTest {
+    @Test
+    public void testGetClipboardContentChangeTimeInMillis() {
+        // Upon launch, the clipboard should be at start of epoch, i.e., ancient.
+        Clipboard clipboard = new Clipboard(new AdvancedMockContext());

[Ted C, 2017/03/23 20:59:31]

The AndvancedMockContext is more designed for instrumentation tests.  Here, much
of this is done for you by Robolectric.  You might be able to use
org.robolectric.RuntimeEnvironment.application here as the context.

I think a dummy implementation is already provided for you here:
https://cs.chromium.org/chromium/src/third_party/robolectric/robolectric/robo...

There is the concept of Shadows in Robolectric as well, which is likely how you
would need to mock it out.  But you simply might not need to, you could likely
just use the above context to getSystemService and then push clip data yourself
if you needed to test (things like the comment I wrote below, which I wrote
first :-P)

+        assertEquals(0, clipboard.getClipboardContentChangeTimeInMillis());
+        // After updating the clipboard, it should have a new time.
+        clipboard.onPrimaryClipChanged();
+        assertTrue(clipboard.getClipboardContentChangeTimeInMillis() > 0);
+    }

[Ted C, 2017/03/23 20:59:31]

Maybe we could add a test where we mock the ClipboardManager in your mock
context (we could overwrite getSystemService in a local AdvancedMockContext and
return our own manager that can provide getPrimaryClip to be mocked.  Then we
could add a test where we notify onPrimaryClipChanged without the text changing
and ensure the change time doesn't increase.

And now that i've written all of that, we could likely just duplicate the test
above and call onPrimaryClipChanged again.  It's not like the text will change
even if empty so it should work as is.

[Mark P, 2017/03/23 23:40:32]

Why would we want to test that the change time doesn't increase with
onPrimaryClipChanged changed without changing the text?  The code explicitly
updates the time in case, and already has a comment to this effect.

+}