I made a Test where I send an invalid JSON, and it should catch me a JSONException.

When I run the test, it fails and shows me a JSONException, Why doesn't test catch it?

@Test (expected = JSONException.class)
public void testExtraFieldsJsonException() {
    String json = "wrong_data";
    fragment.decodeJson(json);
}

I use org.json.JSONException.

Test result.

org.json.JSONException: Value wrong_data of type java.lang.String cannot be converted to JSONObject
    at org.json.JSON.typeMismatch(JSON.java:111)
    at org.json.JSONObject.<init>(JSONObject.java:158)
    at org.json.JSONObject.<init>(JSONObject.java:171)
    at co.some.mainactivities.ProfileFragment.extraFields(ProfileFragment.java:154)
    at co.some.mainactivities.ProfileFragment.callExtraFields(ProfileFragment.java:243)
    at co.some.mainactivities.TestProfileFragment.testExtraFieldsJsonException(TestProfileFragment.java:41)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:50)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:12)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:47)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:17)
    at org.junit.internal.runners.statements.ExpectException.evaluate(ExpectException.java:19)
    at org.junit.internal.runners.statements.RunBefores.evaluate(RunBefores.java:26)
    at org.junit.internal.runners.statements.RunAfters.evaluate(RunAfters.java:27)
    at org.robolectric.RobolectricTestRunner$2.evaluate(RobolectricTestRunner.java:250)
    at org.junit.runners.ParentRunner.runLeaf(ParentRunner.java:325)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:78)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:57)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:290)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:71)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:288)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:58)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:268)
    at org.robolectric.RobolectricTestRunner$1.evaluate(RobolectricTestRunner.java:177)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:363)

it fails in the new JSONObject(json);

private void decodeJson(String json) {
    try {
     JSONObject json = new JSONObject(json);
     int fieldsQuantity = json.getJSONObject("extra_fields").length();
     //....
    }
    catch (JSONException e) {
        e.printStackTrace();
    }
}

You are catching the exception in decodeJSON, so it's not propagating up to the test.

If you want the exception to be thrown to callers of decodeJSON, such as your test, remove the try-catch and add throws JSONException to the function signature.

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