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How to test element of custom sdk android unit test

I've started learning android unit tests, but it looks very hard to find some good guides or information. Every example have a stupid example about 2+2 = 4
Say I write a little SDK which has few functions
MySdk.Init(Context context)
MySdk.CallTask()
I create an androidTest file
How should I call my SDK functions to check how they work? Somewhere required parameters like int/string/context. I just really don't understand, please help me.
This is what I've tried
public class AndroidTest {
private Activity context;
//default test
#Test
public void addition_correct() throws Exception {
assertEquals(4, 2 + 2);
}
#Test
public void checkContext() {
context = getActivity();
assertNotNull(context);
}
#Test
public void testInitPhase() {
MySdk.Init(context, new SdkInitializationListener() {
#Override
public void onInitializationSuccessful(String adv_id) {
assert (adv_id != null);
}
#Override
public void onInitializationError() {
}
});
}
}
For context i was tried context = new mockContext();. It's passed as context = null and my SDK failed with initialization.

Unit tests are mainly about testing an individual class in isolation, so that you can check if individual public methods of a class behave as you intend them to, and continue to do so if you change that class' code in the future. Let's say you have a class like this:
public class UtilityFunctions {
public int double(int value) {
return value * 2;
}
public String mirror(String value) {
if (value == null) return "";
return value + new StringBuilder(value).reverse().toString();
}
}
You want to test these two methods with:
valid input values, and check the output is as expected
invalid values, and check that errors are handled accordingly (and the correct exceptions thrown if necessary)
So a test class for the above class may look like this
#RunWith(JUnit4.class)
public class UtilityFunctionsTest {
private UtilityFunctions utility;
#Before
public void setUp() {
// Initialises any conditions before each test
utility = new UtilityFunctions();
}
#Test
public void testDoubleFunction() {
assertEquals(2, utility.double(1));
assertEquals(8, utility.double(4));
assertEquals(-12, utility.double(-6));
assertEquals(0, utility.double(0));
}
#Test
public void testMirror() {
assertEquals("", utility.mirror(null));
assertEquals("", utility.mirror(""));
assertEquals("aa", utility.mirror("a"));
assertEquals("MirrorrorriM", utility.mirror("Mirror"));
}
}
These standard Java unit tests are run from the test directory. However, you'll need to run tests in the androidTest directory whenever you're using Android-specific classes such as Context. If you're creating a MockContext, you're simply creating an empty Context whose methods don't do anything.
Without me knowing anything about what your MySDK does, I think you may need to pass a fully-functioning Context into your class for your tests. The Android JUnit runner does provide this with InstrumentationRegistry.getTargetContext(), so for your example, you may need to add this #Before method:
#Before
public void setUp() {
context = InstrumentationRegistry.getTargetContext();
}
You'll also need to remove the context = getActivity(); line from your first test.

How to run unit test + Espresso repeatedly?

I need to collect some data on my current app in order to analyse performance speed by checking the average ellapsed time during Activity start up. I would like to run a test battery where the activity is started 10, 100, 1000 and 5000 times. For each test, it should remain open for at least 10 seconds (time needed to collect all data that happens asynchronously). What I want is exactly this behaviour without having to write these many methods:
#RunWith(AndroidJUnit4.class)
#LargeTest
public class TestStreamLoadingPerformance {
private static final long TIME_OUT = 2;
private static final long WAITING_TIME = 10000;
#Rule
public ActivityTestRule mActivityRule = new ActivityTestRule(HomepageActivity.class);
private ElapsedTimeIdlingResource mIdleRes = new ElapsedTimeIdlingResource(WAITING_TIME);
#Before
public void setUp() {
IdlingPolicies.setMasterPolicyTimeout(TIME_OUT, TimeUnit.HOURS);
IdlingPolicies.setIdlingResourceTimeout(TIME_OUT, TimeUnit.HOURS);
Espresso.registerIdlingResources(mIdleRes);
}
#After
public void tearDown() {
Espresso.unregisterIdlingResources(mIdleRes);
}
#Test
public void test01() {
}
#Test
public void test02() {
}
#Test
public void test03() {
}
#Test
public void test04() {
}
#Test
public void test05() {
}
#Test
public void test06() {
}
#Test
public void test07() {
}
#Test
public void test08() {
}
#Test
public void test09() {
}
}

With the help of #Be_negative comments, this blog post and this answer, I was able to solve the problem with the code below:
#RunWith(AndroidJUnit4.class)
#LargeTest
public class TestStreamLoadingPerformance {
#Rule
public ActivityTestRule mActivityRule = new ActivityTestRule(HomepageActivity.class, false, false);
#Rule
public RepeatRule mRepeatRule = new RepeatRule();
#After
public void tearDown() {
closeActivity();
}
private void closeActivity() {
final int N = 10;
try {
for (int i = 0; i < N; i++) {
Espresso.pressBack();
}
} catch (NoActivityResumedException e) {
Log.e(TestStreamLoadingPerformance.class.getSimpleName(), "Unable to close activities", e);
}
}
#Test
#RepeatRule.Repeat(times = 10)
public void collectData() {
mActivityRule.launchActivity(null);
}
}
import org.junit.rules.TestRule;
import org.junit.runner.Description;
import org.junit.runners.model.Statement;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
public class RepeatRule implements TestRule {
#Retention(RetentionPolicy.RUNTIME)
#Target({
java.lang.annotation.ElementType.METHOD
})
public #interface Repeat {
public abstract int times();
}
private static class RepeatStatement extends Statement {
private final int times;
private final Statement statement;
private RepeatStatement(int times, Statement statement) {
this.times = times;
this.statement = statement;
}
#Override
public void evaluate() throws Throwable {
for (int i = 0; i < times; i++) {
statement.evaluate();
}
}
}
#Override
public Statement apply(Statement statement, Description description) {
Statement result = statement;
Repeat repeat = description.getAnnotation(Repeat.class);
if (repeat != null) {
int times = repeat.times();
result = new RepeatStatement(times, statement);
}
return result;
}
}

The easiest (as in least amount of new code required) way to do this is to run the test as a parametrized test (annotate with an #RunWith(Parameterized.class) and add a method to provide 10 empty parameters). That way the framework will run the test 10 times.
This test would need to be the only test in the class, or better put all test methods should need to be run 10 times in the class.
Here is an example:
#RunWith(Parameterized.class)
public class RunTenTimes {
#Parameterized.Parameters
public static List<Object[]> data() {
return Arrays.asList(new Object[10][0]);
}
public RunTenTimes() {
}
#Test
public void runsTenTimes() {
System.out.println("run");
}
}
With the above, it is possible to even do it with a parameter-less constructor, but I'm not sure if the framework authors intended that, or if that will break in the future.
If you are implementing your own runner, then you could have the runner run the test 10 times. If you are using a third party runner, then with 4.7, you can use the new #Rule annotation and implement the MethodRule interface so that it takes the statement and executes it 10 times in a for loop. The current disadvantage of this approach is that #Before and #After get run only once. This will likely change in the next version of JUnit (the #Before will run after the #Rule), but regardless you will be acting on the same instance of the object (something that isn't true of the Parameterized runner). This assumes that whatever runner you are running the class with correctly recognizes the #Rule annotations. That is only the case if it is delegating to the JUnit runners.
If you are running with a custom runner that does not recognize the #Rule annotation, then you are really stuck with having to write your own runner that delegates appropriately to that Runner and runs it 10 times.
Note that there are other ways to potentially solve this (such as the Theories runner) but they all require a runner. Unfortunately JUnit does not currently support layers of runners. That is a runner that chains other runners.

I had a very similar issue and as a result I've created a library to run Android UI tests multiple times. Might be useful in your case: https://github.com/stepstone-tech/AndroidTestXRunner

Getting Dagger to inject mock objects when doing Espresso functional testing for Android

I've recently gone whole-hog with Dagger because the concept of DI makes complete sense. One of the nicer "by-products" of DI (as Jake Wharton put in one of his presentations) is easier testability.
So now I'm basically using Espresso to do some functional testing, and I want to be able to inject dummy/mock data to the application and have the activity show them up. I'm guessing since, this is one of the biggest advantages of DI, this should be a relatively simple ask. For some reason though, I can't seem to wrap my head around it. Any help would be much appreciated. Here's what I have so far (I've written up an example that reflects my current setup):
public class MyActivity
extends MyBaseActivity {
#Inject Navigator _navigator;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
MyApplication.get(this).inject(this);
// ...
setupViews();
}
private void setupViews() {
myTextView.setText(getMyLabel());
}
public String getMyLabel() {
return _navigator.getSpecialText(); // "Special Text"
}
}
These are my dagger modules:
// Navigation Module
#Module(library = true)
public class NavigationModule {
private Navigator _nav;
#Provides
#Singleton
Navigator provideANavigator() {
if (_nav == null) {
_nav = new Navigator();
}
return _nav;
}
}
// App level module
#Module(
includes = { SessionModule.class, NavigationModule.class },
injects = { MyApplication.class,
MyActivity.class,
// ...
})
public class App {
private final Context _appContext;
AppModule(Context appContext) {
_appContext = appContext;
}
// ...
}
In my Espresso Test, I'm trying to insert a mock module like so:
public class MyActivityTest
extends ActivityInstrumentationTestCase2<MyActivity> {
public MyActivityTest() {
super(MyActivity.class);
}
#Override
public void setUp() throws Exception {
super.setUp();
ObjectGraph og = ((MyApplication) getActivity().getApplication()).getObjectGraph().plus(new TestNavigationModule());
og.inject(getActivity());
}
public void test_SeeSpecialText() {
onView(withId(R.id.my_text_view)).check(matches(withText(
"Special Dummy Text")));
}
#Module(includes = NavigationModule.class,
injects = { MyActivityTest.class, MyActivity.class },
overrides = true,
library = true)
static class TestNavigationModule {
#Provides
#Singleton
Navigator provideANavigator() {
return new DummyNavigator(); // that returns "Special Dummy Text"
}
}
}
This is not working at all. My Espresso tests run, but the TestNavigationModule is completely ignored... arr... :(
What am I doing wrong? Is there a better approach to mocking modules out with Espresso? I've searched and seen examples of Robolectric, Mockito etc. being used. But I just want pure Espresso tests and need to swap out a module with my mock one. How should i be doing this?
EDIT:
So I went with #user3399328 approach of having a static test module list definition, checking for null and then adding it in my Application class. I'm still not getting my Test injected version of the class though. I have a feeling though, its probably something wrong with dagger test module definition, and not my espresso lifecycle. The reason I'm making the assumption is that I add debug statements and find that the static test module is non-empty at time of injection in the application class. Could you point me to a direction of what I could possibly be doing wrong. Here are code snippets of my definitions:
MyApplication:
#Override
public void onCreate() {
// ...
mObjectGraph = ObjectGraph.create(Modules.list(this));
// ...
}
Modules:
public class Modules {
public static List<Object> _testModules = null;
public static Object[] list(MyApplication app) {
// return new Object[]{ new AppModule(app) };
List<Object> modules = new ArrayList<Object>();
modules.add(new AppModule(app));
if (_testModules == null) {
Log.d("No test modules");
} else {
Log.d("Test modules found");
}
if (_testModules != null) {
modules.addAll(_testModules);
}
return modules.toArray();
}
}
Modified test module within my test class:
#Module(overrides = true, library = true)
public static class TestNavigationModule {
#Provides
#Singleton
Navigator provideANavigator()() {
Navigator navigator = new Navigator();
navigator.setSpecialText("Dummy Text");
return navigator;
}
}

With Dagger 2 and Espresso 2 things have indeed improved. This is how a test case could look like now. Notice that ContributorsModel is provided by Dagger. The full demo available here: https://github.com/pmellaaho/RxApp
#RunWith(AndroidJUnit4.class)
public class MainActivityTest {
ContributorsModel mModel;
#Singleton
#Component(modules = MockNetworkModule.class)
public interface MockNetworkComponent extends RxApp.NetworkComponent {
}
#Rule
public ActivityTestRule<MainActivity> mActivityRule = new ActivityTestRule<>(
MainActivity.class,
true, // initialTouchMode
false); // launchActivity.
#Before
public void setUp() {
Instrumentation instrumentation = InstrumentationRegistry.getInstrumentation();
RxApp app = (RxApp) instrumentation.getTargetContext()
.getApplicationContext();
MockNetworkComponent testComponent = DaggerMainActivityTest_MockNetworkComponent.builder()
.mockNetworkModule(new MockNetworkModule())
.build();
app.setComponent(testComponent);
mModel = testComponent.contributorsModel();
}
#Test
public void listWithTwoContributors() {
// GIVEN
List<Contributor> tmpList = new ArrayList<>();
tmpList.add(new Contributor("Jesse", 600));
tmpList.add(new Contributor("Jake", 200));
Observable<List<Contributor>> testObservable = Observable.just(tmpList);
Mockito.when(mModel.getContributors(anyString(), anyString()))
.thenReturn(testObservable);
// WHEN
mActivityRule.launchActivity(new Intent());
onView(withId(R.id.startBtn)).perform(click());
// THEN
onView(ViewMatchers.nthChildOf(withId(R.id.recyclerView), 0))
.check(matches(hasDescendant(withText("Jesse"))));
onView(ViewMatchers.nthChildOf(withId(R.id.recyclerView), 0))
.check(matches(hasDescendant(withText("600"))));
onView(ViewMatchers.nthChildOf(withId(R.id.recyclerView), 1))
.check(matches(hasDescendant(withText("Jake"))));
onView(ViewMatchers.nthChildOf(withId(R.id.recyclerView), 1))
.check(matches(hasDescendant(withText("200"))));
}

Your approach doesn't work because it only happens once, and as Matt mentioned, when the activity's real injection code runs, it will wipe out any variables injected by your special object graph.
There are two ways to get this to work.
The quick way: make a public static variable in your activity so a test can assign an override module and have the actual activity code always include this module if it's not null (which will only happen in tests). It's similar to my answer here just for your activity base class instead of application.
The longer, probably better way: refactor your code so that all activity injection (and more importantly graph creation) happens in one class, something like ActivityInjectHelper. In your test package, create another class named ActivityInjectHelper with the exact same package path that implements the same methods, except also plusses your test modules. Because test classes are loaded first, your application will execute with the testing ActivityInjectHelper. Again it's similar to my answer here just for a different class.
UPDATE:
I see you've posted more code and it's close to working, but no cigar. For both activities and applications, the test module needs to be snuck in before onCreate() runs. When dealing with activity object graphs, anytime before the test's getActivity() is fine. When dealing with applications, it's a bit harder because onCreate() has already been called by the time setUp() runs. Luckily, doing it in the test's constructor works - the application hasn't been created at that point. I briefly mention this in my first link.

The call to getActivity will actually start your activity calling onCreate in the process which means you won't be getting your test modules added to the graph in time to be used. Using activityInstrumentationTestcase2 you can't really inject properly at the activity scope. I've worked around this by using my application to provide dependencies to my activities and then inject mock objects into it which the activities will use. It's not ideal but it works. You can use an event bus like Otto to help provide dependencies.

EDIT: the below in post form http://systemdotrun.blogspot.co.uk/2014/11/android-testing-with-dagger-retrofit.html
To test an Activity using Espresso + Dagger I have done the below
Inspired by the answer from #user3399328 I have a DaggerHelper class inside my Application class, which allows the test case to override the #Providers using Test #Modules which supply mocks. As long as
1) This is done before the testCases getActivity() call is made (as my inject call happens in my activity inside Activity.onCreate)
2) tearDown removes the test modules from the object graph.
Examples below.
Note: this is not ideal as this is subject to similar pitfalls of using factory methods for IoC but at least this way its only ever a single call in tearDown() to bring the system under test back to normal.
The DaggerHelper inside my Application class
public static class DaggerHelper
{
private static ObjectGraph sObjectGraph;
private static final List<Object> productionModules;
static
{
productionModules = new ArrayList<Object>();
productionModules.add(new DefaultModule());
}
/**
* Init the dagger object graph with production modules
*/
public static void initProductionModules()
{
initWithModules(productionModules);
}
/**
* If passing in test modules make sure to override = true in the #Module annotation
*/
public static void initWithTestModules(Object... testModules)
{
initWithModules(getModulesAsList(testModules));
}
private static void initWithModules(List<Object> modules)
{
sObjectGraph = ObjectGraph.create(modules.toArray());
}
private static List<Object> getModulesAsList(Object... extraModules)
{
List<Object> allModules = new ArrayList<Object>();
allModules.addAll(productionModules);
allModules.addAll(Arrays.asList(extraModules));
return allModules;
}
/**
* Dagger convenience method - will inject the fields of the passed in object
*/
public static void inject(Object object) {
sObjectGraph.inject(object);
}
}
My Test module inside my test class
#Module (
overrides = true,
injects = ActivityUnderTest.class
)
static class TestDataPersisterModule {
#Provides
#Singleton
DataPersister provideMockDataPersister() {
return new DataPersister(){
#Override
public void persistDose()
{
throw new RuntimeException("Mock DI!"); //just a test to see if being called
}
};
}
}
Test method
public void testSomething()
{
MyApp.DaggerHelper.initWithTestModules(new TestDataPersisterModule());
getActivity();
...
}
Tear down
#Override
public void tearDown() throws Exception
{
super.tearDown();
//reset
MyApp.DaggerHelper.initProductionModules();
}

How to determine if Android Application is started with JUnit testing instrumentation?

I need to determine in runtime from code if the application is run under TestInstrumentation.
I could initialize the test environment with some env/system variable, but Eclipse ADK launch configuration would not allow me to do that.
Default Android system properties and environment do not to have any data about it. Moreover, they are identically same, whether the application is started regularly or under test.
This one could be a solution: Is it possible to find out if an Android application runs as part of an instrumentation test but since I do not test activities, all proposed methods there won't work. The ActivityManager.isRunningInTestHarness() method uses this under the hood:
SystemProperties.getBoolean("ro.test_harness")
which always returns false in my case. (To work with the hidden android.os.SystemProperties class I use reflection).
What else can I do to try to determine from inside the application if it's under test?

I have found one hacky solution: out of the application one can try to load a class from the testing package. The appication classloader surprisingly can load classes by name from the testing project if it was run under test. In other case the class is not found.
private static boolean isTestMode() {
boolean result;
try {
application.getClassLoader().loadClass("foo.bar.test.SomeTest");
// alternatively (see the comment below):
// Class.forName("foo.bar.test.SomeTest");
result = true;
} catch (final Exception e) {
result = false;
}
return result;
}
I admit this is not elegant but it works. Will be grateful for the proper solution.

The isTestMode() solution did not work for me on Android Studio 1.2.1.1. Almighty Krzysztof from our company tweaked your method by using:
Class.forName("foo.bar.test.SomeTest");
instead of getClassLoader(). Thanks for Krzysztof!

We created a solution to pass parameters to the MainActivity and use it inside the onCreate method, enabling you to define how the Activity will be created.
In MainActivity class, we created some constants, which could also be an enum. We created a static attribute too.
public class MainActivity {
public static final int APPLICATION_MODE = 5;
public static final int UNIT_TEST_MODE = 10;
public static final int OTHER_MODE = 15;
public static int activityMode = APPLICATION_MODE;
(...)
#Override
protected void onCreate(Bundle icicle) {
super.onCreate(icicle);
switch (activityMode) {
case OTHER_MODE:
(...)
break;
case UNIT_TEST_MODE:
Log.d(TAG, "Is in Test Mode!");
break;
case APPLICATION_MODE:
(...)
break;
}
(...)
}
(...)
}
We made MainActivityTest class abstract, created a setApplicationMode and called this method inside the setUp() method, before calling the super.setUp() method.
public abstract class MainActivityTest extends ActivityInstrumentationTestCase2<MainActivity> {
protected void setUp() throws Exception {
setApplicationMode(); // <=====
super.setUp();
getActivity();
(...)
}
(...)
public void setApplicationMode() {
MainActivity.activityMode = MainActivity.UNIT_TEST_MODE;
}
}
All other test classes inherit from MainActivityTest, if we want it to have another behaviour, we can simply override the setApplicationMode method.
public class OtherMainActivityTest extends MainActivityTest {
(...)
#Override
public void setApplicationMode() {
MainActivity.activityMode = MainActivity.OTHER_MODE;
}
}
The user nathan-almeida is the friend that is co-author of this solution.

How to test just one line source in Android?

I have to make a Android Junit Test.
And the source just like this way:
public class A extends Activity{
private classB mB;
private int mType = 2;
somebutton.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
mB.showDialog(
new DialogInterface.OnClickListener() {
public void onClick(DialogInterface dialog, int which) {
//next line is the modified and I have to make test file
mB.setType(mType);
}
}
)
}
}
}
And I could let the test click button and prepare all other needed things, but I want to how to assertTrue? And there is no "getType()" and the "Type" in "mB" is private.
Thank you for your time.

Unit-Testing is diffucult on android because all the SDK classes are stubbed out and are good only for compiling agains them, and running unit tests on device or emulator is PITA
Alternative is mocking. [Most] Suitable mock framework is JMockit ( it can mock final private static - also everything you can dream of)
Here is small example showcasing using of jmockit against android classes:
/**
* shall inject assignable views into
*/
#Test
public void testSimpleInjection(#Mocked final WithInjectableViews injectable,
#Mocked final TextView textView,
#Mocked final Button button) {
new Expectations() {
{
injectable.findViewById(239);
returns(textView);
injectable.findViewById(555);
returns(button);
}
};
ViewInjector.startActivity(injectable);
assertEquals(textView, Deencapsulation.getField(injectable, "asView"));
assertEquals(button, Deencapsulation.getField(injectable, "button"));
assertNull(Deencapsulation.getField(injectable, "notInjected"));
}
class WithInjectableViews extends Activity {
// shall be injected
#InjectView(id = 239)
private android.view.View asView;
#InjectView(id = 555)
private Button button;
// shall be left alone
private View notInjected = null;
}
(full source: https://github.com/ko5tik/andject/blob/master/src/test/java/de/pribluda/android/andject/ViewInjectionTest.java)
However, it is diffucult to mock up anonymous inner classes, so you may have to refactor somehow. As to access to provate fields and mewthods - jmockit provides untility class Deencalsulation - it ignores almost all access constraints.