View assertions

The assertions introduced earlier handle a variety of types as parameters, but they are only intended to test simple conditions or simple objects.

For example, we have asertEquals(short expected, short actual) to test short values, assertEquals(int expected, int actual) to test integer values, assertEquals(Object expected, Object expected) to test any Object instance, and so on.

Usually, while testing user interfaces in Android, you will face the problem of more sophisticated methods, which are mainly related with Views. In this respect, Android provides a class with plenty of assertions in android.test.ViewAsserts (see http://developer.android.com/reference/android/test/ViewAsserts.html for more details), which test relationships between Views and their absolute and relative positions on the screen.

These methods are also overloaded to provide different conditions. Among the assertions, we can find the following:

The following example shows how you can use ViewAssertions to test the user interface layout:

  public void testUserInterfaceLayout() {
    int margin = 0;
    View origin = mActivity.getWindow().getDecorView();
    assertOnScreen(origin, editText);
    assertOnScreen(origin, button);
    assertRightAligned(editText, button, margin);
  }

The assertOnScreen method uses an origin to start looking for the requested Views. In this case, we are using the top-level window decor View. If, for some reason, you don't need to go that high in the hierarchy, or if this approach is not suitable for your test, you may use another root View in the hierarchy, for example View.getRootView(), which, in our concrete example, would be editText.getRootView().