Android Local unit test/Instrumentation Test

reference 1
reference for unit test

basic:

differences between Local unit test and Instrumentation Test:
Local unit test: can just run on JVM, doesn't need Android framework
Instrumentation Test: can test Android component(Activity, Service...) and UI

create Class for testing(both local unit test and instrumentation test) in app/src/androidTest/java/<package_name>

set build.gradle:
dependencies {
    androidTestCompile 'junit:junit:4.12'
    androidTestCompile 'com.android.support.test:runner:0.4'
    // Set this dependency to use JUnit 4 rules
    androidTestCompile 'com.android.support.test:rules:0.4'
    androidTestCompile 'com.android.support:support-annotations:23.1.1'
}

mokito for mocking context seems useless if we use the sample code snippet here (the Context is null and MockitoAnnotations.initMocks can't work

sample Local unit test

import org.junit.Test;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertThat;
import static org.junit.Assert.assertTrue;
public class MyUnitTest {
    @Test
    public void testOne() {

        assertTrue("123".equals("123"));
    }
}

sample Instrumentation test

import android.test.ActivityInstrumentationTestCase2;
import android.test.UiThreadTest;
import android.widget.Toast;

//JUnit4
public class ActivityFunctionTest extends ActivityInstrumentationTestCase2 {
    public ActivityFunctionTest(Class activityClass) {
        super(activityClass);
    }

    public ActivityFunctionTest(){
        super(MainMenuAcitivity.class);
    }

    public void testSetText() throws Exception {

        // set text
        getActivity().runOnUiThread(new Runnable() {

            @Override
            public void run() {
                MainMenuAcitivity activity = getActivity();
                Toast.makeText(activity, "test toast 2", Toast.LENGTH_SHORT).show();
            }
        });

        getInstrumentation().waitForIdleSync();

    }

    @UiThreadTest
    public void testSetTextWithAnnotation() throws Exception {

        MainMenuAcitivity activity = getActivity();
        Toast.makeText(activity, "test toast", Toast.LENGTH_SHORT).show();

    }
}

monkey command:
adb shell monkey -p <package_name> -v <number_of_events>