shell/platform/android/test/io/flutter/plugin/platform/SingleViewPresentationTest.java

package io.flutter.plugin.platform;

import static junit.framework.Assert.assertEquals;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.spy;
import static org.mockito.Mockito.when;

import android.annotation.TargetApi;
import android.content.Context;
import android.hardware.display.DisplayManager;
import android.view.Display;
import android.view.inputmethod.InputMethodManager;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.robolectric.RobolectricTestRunner;
import org.robolectric.RuntimeEnvironment;
import org.robolectric.annotation.Config;
import org.robolectric.shadows.ShadowDisplay;
import org.robolectric.shadows.ShadowDisplayManager;
import org.robolectric.shadows.ShadowInputMethodManager;

@Config(
    manifest = Config.NONE,
    shadows = {ShadowInputMethodManager.class, ShadowDisplayManager.class, ShadowDisplay.class})
@RunWith(RobolectricTestRunner.class)
@TargetApi(28)
public class SingleViewPresentationTest {
  @Test
  public void returnsOuterContextInputMethodManager() {
    // There's a bug in Android Q caused by the IMM being instanced per display.
    // https://github.com/flutter/flutter/issues/38375. We need the context returned by
    // SingleViewPresentation to be consistent from its instantiation instead of defaulting to
    // what the system would have returned at call time.

    // It's not possible to set up the exact same conditions as the unit test in the bug here,
    // but we can make sure that we're wrapping the Context passed in at instantiation time and
    // returning the same InputMethodManager from it. This test passes in a Spy context instance
    // that initially returns a mock. Without the bugfix this test falls back to Robolectric's
    // system service instead of the spy's and fails.

    // Create an SVP under test with a Context that returns a local IMM mock.
    Context context = spy(RuntimeEnvironment.application);
    InputMethodManager expected = mock(InputMethodManager.class);
    when(context.getSystemService(Context.INPUT_METHOD_SERVICE)).thenReturn(expected);
    DisplayManager dm = (DisplayManager) context.getSystemService(Context.DISPLAY_SERVICE);
    SingleViewPresentation svp =
        new SingleViewPresentation(context, dm.getDisplay(0), null, null, null, false);

    // Get the IMM from the SVP's context.
    InputMethodManager actual =
        (InputMethodManager) svp.getContext().getSystemService(Context.INPUT_METHOD_SERVICE);

    // This should be the mocked instance from construction, not the IMM from the greater
    // Android OS (or Robolectric's shadow, in this case).
    assertEquals(expected, actual);
  }

  @Test
  public void returnsOuterContextInputMethodManager_createDisplayContext() {
    // The IMM should also persist across display contexts created from the base context.

    // Create an SVP under test with a Context that returns a local IMM mock.
    Context context = spy(RuntimeEnvironment.application);
    InputMethodManager expected = mock(InputMethodManager.class);
    when(context.getSystemService(Context.INPUT_METHOD_SERVICE)).thenReturn(expected);
    Display display =
        ((DisplayManager) context.getSystemService(Context.DISPLAY_SERVICE)).getDisplay(0);
    SingleViewPresentation svp =
        new SingleViewPresentation(context, display, null, null, null, false);

    // Get the IMM from the SVP's context.
    InputMethodManager actual =
        (InputMethodManager)
            svp.getContext()
                .createDisplayContext(display)
                .getSystemService(Context.INPUT_METHOD_SERVICE);

    // This should be the mocked instance from construction, not the IMM from the greater
    // Android OS (or Robolectric's shadow, in this case).
    assertEquals(expected, actual);
  }
}