Why is my JSONObject related unit test failing?

Question

I'm running my tests using gradle testFlavorType

JSONObject jsonObject1 = new JSONObject(); JSONObject jsonObject2 = new JSONObject(); jsonObject1.put("test", "test"); jsonObject2.put("test", "test"); assertEquals(jsonObject1.get("test"), jsonObject2.get("test")); 

The above test succeeds.

jsonObject = new SlackMessageRequest(channel, message).buildBody(); String channelAssertion = jsonObject.getString(SlackMessageRequest.JSON_KEY_CHANNEL); String messageAssertion = jsonObject.getString(SlackMessageRequest.JSON_KEY_TEXT); assertEquals(channel, channelAssertion); assertEquals(message, messageAssertion); 

But the above two requests fail. The stack trace says that channelAssertion and messageAssertion are null, but not sure why. My question is: Why are the above two asserts failing?

Below is the SlackMessageRequest.

public class SlackMessageRequest         extends BaseRequest {     // region Variables      public static final String JSON_KEY_TEXT = "text";     public static final String JSON_KEY_CHANNEL = "channel";      private String mChannel;     private String mMessage;      // endregion      // region Constructors      public SlackMessageRequest(String channel, String message) {         mChannel = channel;         mMessage = message;     }      // endregion      // region Methods      @Override     public MethodType getMethodType() {         return MethodType.POST;     }          @Override     public JSONObject buildBody() throws JSONException {         JSONObject body = new JSONObject();         body.put(JSON_KEY_TEXT, getMessage());         body.put(JSON_KEY_CHANNEL, getChannel());         return body;     }      @Override     public String getUrl() {         return "http://localhost:1337";     }      public String getMessage() {         return mMessage;     }      public String getChannel() {         return mChannel;     }  // endregion } 

Below is the stacktrace:

junit.framework.ComparisonFailure: expected:<@tk> but was:<null>     at junit.framework.Assert.assertEquals(Assert.java:100)     at junit.framework.Assert.assertEquals(Assert.java:107)     at junit.framework.TestCase.assertEquals(TestCase.java:269)     at com.example.app.http.request.SlackMessageRequestTest.testBuildBody(SlackMessageRequestTest.java:30)     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)     at java.lang.reflect.Method.invoke(Method.java:483)     at junit.framework.TestCase.runTest(TestCase.java:176)     at junit.framework.TestCase.runBare(TestCase.java:141)     at junit.framework.TestResult$1.protect(TestResult.java:122)     at junit.framework.TestResult.runProtected(TestResult.java:142)     at junit.framework.TestResult.run(TestResult.java:125)     at junit.framework.TestCase.run(TestCase.java:129)     at junit.framework.TestSuite.runTest(TestSuite.java:252)     at junit.framework.TestSuite.run(TestSuite.java:247)     at org.junit.internal.runners.JUnit38ClassRunner.run(JUnit38ClassRunner.java:86)     at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecuter.runTestClass(JUnitTestClassExecuter.java:86)     at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassExecuter.execute(JUnitTestClassExecuter.java:49)     at org.gradle.api.internal.tasks.testing.junit.JUnitTestClassProcessor.processTestClass(JUnitTestClassProcessor.java:64)     at org.gradle.api.internal.tasks.testing.SuiteTestClassProcessor.processTestClass(SuiteTestClassProcessor.java:50)     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)     at java.lang.reflect.Method.invoke(Method.java:483)     at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35)     at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)     at org.gradle.messaging.dispatch.ContextClassLoaderDispatch.dispatch(ContextClassLoaderDispatch.java:32)     at org.gradle.messaging.dispatch.ProxyDispatchAdapter$DispatchingInvocationHandler.invoke(ProxyDispatchAdapter.java:93)     at com.sun.proxy.$Proxy2.processTestClass(Unknown Source)     at org.gradle.api.internal.tasks.testing.worker.TestWorker.processTestClass(TestWorker.java:106)     at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)     at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)     at java.lang.reflect.Method.invoke(Method.java:483)     at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:35)     at org.gradle.messaging.dispatch.ReflectionDispatch.dispatch(ReflectionDispatch.java:24)     at org.gradle.messaging.remote.internal.hub.MessageHub$Handler.run(MessageHub.java:360)     at org.gradle.internal.concurrent.DefaultExecutorFactory$StoppableExecutorImpl$1.run(DefaultExecutorFactory.java:64)     at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)     at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)     at java.lang.Thread.run(Thread.java:745) 

EDIT 5:55PM EST

I've figured out that I can log with System.out.println("") and then see the results by running gradle testFlavorType --debug and by trial and error I've discovered the following weird situation:

@Override public JSONObject buildBody() throws JSONException {     System.out.println("buildBody mChannel = " + mChannel);     System.out.println("buildBody mMessage = " + mMessage);     JSONObject body = new JSONObject();     body.put(JSON_KEY_TEXT, getMessage());     body.put(JSON_KEY_CHANNEL, getChannel());      if (body.length() != 0) {         Iterator<String> keys = body.keys();          if (keys.hasNext()) {             do {                 String key = keys.next();                 System.out.println("keys: " + key);             } while (keys.hasNext());         }     } else {         System.out.println("There are no keys????");     }      return body; } 

For some reason, "There are no keys????" is printing out?!?!?!?! Why?!

EDIT 6:20PM EST

I've figured out how to debug unit tests. According to the debugger, the assigned JSONObject is returning "null". I have no clue what this means (see below). Since I think this is relevant, my gradle file includes the following:

testOptions {     unitTests.returnDefaultValues = true } 

It's especially strange because if I construct a JSONObject inside the test, then everything works fine. But if it is part of the original application's code, then it doesn't work and does the above.

Answer 1

As Lucas says, JSON is bundled up with the Android SDK, so you are working with a stub.

The current solution is to pull JSON from Maven Central like this:

dependencies {     ...     testImplementation 'org.json:json:20210307' } 

You can replace the version 20210307 with the the latest one depending on the Android API. It is not known which version of the maven artefact corresponds exactly/most closely to what ships with Android.

Alternatively, you can download and include the jar:

dependencies {     ...     testImplementation files('libs/json.jar') } 

Note that you also need to use Android Studio 1.1 or higher and at least build tools version 22.0.0 or above for this to work.

Related issue: #179461

Answer 2

The class JSONObject is part of the android SDK. That means that is not available for unit testing by default.

From http://tools.android.com/tech-docs/unit-testing-support

The android.jar file that is used to run unit tests does not contain any actual code - that is provided by the Android system image on real devices. Instead, all methods throw exceptions (by default). This is to make sure your unit tests only test your code and do not depend on any particular behaviour of the Android platform (that you have not explicitly mocked e.g. using Mockito).

When you set the test options to

testOptions {     unitTests.returnDefaultValues = true } 

you are fixing the "Method ... not mocked." problem, but the outcome is that when your code uses new JSONObject() you are not using the real method, you are using a mock method that doesn't do anything, it just returns a default value. That's the reason the object is null.

You can find different ways of solving the problem in this question: Android methods are not mocked when using Mockito