Android Instrumentation Testing - UI Thread Issues

Question

I am trying to write an Instrumentation Test for my Android app.

I\'m running into some weird threading issues and I can\'t seem to find a solution.

My

Answer 1

You can run portion of your test on the main UI thread with the help of UiThreadTestRule.runOnUiThread(Runnable):

@Rule
public UiThreadTestRule uiThreadTestRule = new UiThreadTestRule();

@Test
public void loadWorkOrder_displaysCorrectly() throws Exception {
    final WorkOrderDetails activity = activityRule.getActivity();

    uiThreadTestRule.runOnUiThread(new Runnable() {
        @Override
        public void run() {
            WorkOrder workOrder = new WorkOrder();
            activity.updateDetails(workOrder);
        }
    });

    //Verify customer info is displayed
    onView(withId(R.id.customer_name))
            .check(matches(withText("John Smith")));
}

In most cases it is simpler to annotate the test method with UiThreadTest, however, it may incur other errors such as java.lang.IllegalStateException: Method cannot be called on the main application thread (on: main).

FYR, here is a quote from UiThreadTest's Javadoc:

Note, due to current JUnit limitation, methods annotated with Before and After will also be executed on the UI Thread. Consider using runOnUiThread(Runnable) if this is an issue.

Please note UiThreadTest (package android.support.test.annotation) mentioned above is different from (UiThreadTest (package android.test)).