如何为使用 AndroidSchedulers.mainThread() 的函数编写测试；来自 RxAndroid答案

【问题标题】：How to write a test for a function that uses AndroidSchedulers.mainThread(); from RxAndroid如何为使用 AndroidSchedulers.mainThread() 的函数编写测试；来自 RxAndroid
【发布时间】：2015-09-02 02:24:25
【问题描述】：

我在测试方法shouldFetchMachineSettings() 中得到一个NullPointerException。通过调试，我意识到控件没有进入可观察对象的成功回调，并且没有启动意图。因此例外。我意识到问题在于使用AndroidSchedulers.mainThread();，但无法找到解决方案。

MachineSettings.java

public class MachineSettings {

    public static void fetch(final FragmentActivity activity, 
                             MachineService machineService, 
                             final ProgressDialog progressDialog) {
        Observable zippedCalls = Observable.zip(
            machineService.getSettings(), 
            machineService.getInfoAsObservable(), 
            machineService.getSupportedLanguages(), 
            new Func3() {


            @Override
            public Object call(final Object response1, 
                               final Object response2, 
                               final Object response3) {
                return new HashMap<String, Object>() {{
                    put(MACHINE_SETTINGS, response1);
                    put(MACHINE_SETTINGS_INFO, response2);
                    put(MACHINE_SETTINGS_LANGUAGES, response3);
                }};
            }

        });

        zippedCalls.subscribeOn(getNewThread())
                .observeOn(getAndroidSchedulerMainThread())
                .subscribe(onSuccess(activity, progressDialog)
                        , onError(activity, progressDialog));

    }

    public static Scheduler getAndroidSchedulerMainThread() {
        return AndroidSchedulers.mainThread();
    }

    public static Scheduler getNewThread() {
        return Schedulers.newThread();
    }

    private static Action1 onSuccess(final FragmentActivity activity, 
                                     final ProgressDialog progressDialog) {
        return new Action1() {

            @Override
            public void call(Object o) {
                Intent intent = new Intent(activity, MachineSettingsActivity_.class);
            // do some action using object o
            activity.startActivity(intent);
            }
        };
    }

    private static Action1<Throwable> onError(final FragmentActivity activity, 
                                              final ProgressDialog progressDialog) {
        return new Action1<Throwable>() {
            @Override
            public void call(Throwable error) {
                // do some action
            }
        };
    }
}

来自 MachineDetailsFragment.java 的调用

if (item.getItemId() == R.id.action_machine_settings) {
    setupProgressDialog();
    MachineSettings.fetch(getActivity(), machineService, progressDialog);
}

在 MachineDetailsFragmentTest.java 中测试

@Test
public void shouldFetchMachineSettings() {

    MenuItem mockMenuItem = mock(MenuItem.class);
    when(mockMenuItem.getItemId()).thenReturn(R.id.action_machine_settings);

    Map<String, Integer> settings = new HashMap() {{put("privacy", 0);}};
    Map<String, Integer> languages = new HashMap() {{put("index_0", 2);}} ;
    Map<String, String> info = new HashMap()  {{put("version", "1");}};
    Observable<Map<String, Integer>> mockSupportedLanguages = Observable.just(languages);
    Observable<Map<String, Integer>> mockSettings = Observable.just(settings);
    Observable<Map<String, String>> mockInfo = Observable.just(info);

    when(machineService.getSupportedLanguages()).thenReturn(mockSupportedLanguages);
    when(machineService.getSettings()).thenReturn(mockSettings);
    when(machineService.getInfoAsObservable()).thenReturn(mockInfo);

    machineDetailFragment.onOptionsItemSelected(mockMenuItem);

    Intent intent = Shadows.shadowOf(activity).peekNextStartedActivity();
    assertThat(intent.getComponent().getClassName(), 
        is(MachineSettingsActivity_.class.getCanonicalName()));

【问题讨论】：

你查看TestSubscriber了吗？
@Maha 你找到解决办法了吗？

标签： java android rx-java rx-android

【解决方案1】：

修改您的类，使其不使用static 方法，并创建一个接受您要使用的两个Schedulers 的构造函数。然后，在您的测试中，您可以使用不同的调度程序，例如 TestScheduler 或 Schedulers.immediate()。

作为一般经验法则：调用其他静态方法（或使用全局状态、单例）的静态方法很难测试。

【讨论】：