MockWebServer 示例

如果你的活動，片段和 UI 需要一些後臺處理，那麼使用的好東西是 MockWebServer，它在 Android 裝置上執行 localy，為你的 UI 帶來封閉且可測試的環境。

https://github.com/square/okhttp/tree/master/mockwebserver

第一步是包括 gradle 依賴：

testCompile 'com.squareup.okhttp3:mockwebserver:(insert latest version)'

現在執行和使用模擬伺服器的步驟是：

• 建立模擬伺服器物件
• 在特定地址和埠啟動它（通常是 localhost：portnumber）
• 將特定請求的響應排入佇列
• 開始測試

在 mockwebserver 的 github 頁面中很好地解釋了這一點，但在我們的例子中，我們希望所有測試都有更好的和可重用的東西，JUnit 規則將在這裡很好地發揮作用：

/**
 *JUnit  rule that starts and stops a mock web server for test runner
*/
 public class MockServerRule extends UiThreadTestRule {

 private MockWebServer mServer;

 public static final int MOCK_WEBSERVER_PORT = 8000;

    @Override
    public Statement apply(final Statement base, Description description) {
        return new Statement() {
            @Override
            public void evaluate() throws Throwable {
                startServer();
                try {
                    base.evaluate();
                } finally {
                    stopServer();
                }
            }
        };
    }

    /**
     * Returns the started web server instance
     *
     * @return mock server
     */
    public MockWebServer server() {
        return mServer;
    }

    public void startServer() throws IOException, NoSuchAlgorithmException {
        mServer = new MockWebServer();
        try {
            mServer(MOCK_WEBSERVER_PORT);
        } catch (IOException e) {
            throw new IllegalStateException(e,"mock server start issue");
        }
    }

    public void stopServer() {
        try {
            mServer.shutdown();
        } catch (IOException e) {
            Timber.e(e, "mock server shutdown error”);
        }
    }
}

現在讓我們假設我們擁有與之前示例完全相同的活動，就在這種情況下，當我們按下按鈕時，應用程式將從網路中獲取某些內容，例如： https ： //someapi.com/name

這將返回一些文字字串，這些文字字串將在快餐欄文字中連線，例如你鍵入的 NAME +文字。

/**
* Testing of the snackbar activity with networking.
**/
@RunWith(AndroidJUnit4.class)
@LargeTest
public class SnackbarActivityTest{
    //espresso rule which tells which activity to start
    @Rule
    public final ActivityTestRule<SnackbarActivity> mActivityRule = 
        new ActivityTestRule<>(SnackbarActivity.class, true, false);

    //start mock web server
    @Rule
    public final MockServerRule mMockServerRule = new MockServerRule();

    @Override
    public void tearDown() throws Exception {
       //same as previous example
    }
    
    @Override
    public void setUp() throws Exception {
       //same as previous example

       **//IMPORTANT:** point your application to your mockwebserver endpoint e.g.
       MyAppConfig.setEndpointURL("http://localhost:8000");
    }
    
    /**
    *Test methods should always start with "testXYZ" and it is a good idea to 
    *name them after the intent what you want to test
    **/
    @Test
    public void testSnackbarIsShown() {
        //setup mockweb server
        mMockServerRule.server().setDispatcher(getDispatcher());

        mActivityRule.launchActivity(null);
        //check is our text entry displayed and enter some text to it
        String textToType="new snackbar text";
        onView(withId(R.id.textEntry)).check(matches(isDisplayed()));
        //we check is our snackbar showing text from mock webserver plus the one we typed
        onView(withId(R.id.textEntry)).perform(typeText("JazzJackTheRabbit" + textToType));
        //click the button to show the snackbar
        onView(withId(R.id.shownSnackbarBtn)).perform(click());
        //assert that a view with snackbar_id with text which we typed and is displayed
        onView(allOf(withId(android.support.design.R.id.snackbar_text), 
        withText(textToType))) .check(matches(isDisplayed()));
    }
    
     /**
     *creates a mock web server dispatcher with prerecorded requests and responses
     **/
    private Dispatcher getDispatcher() {
        final Dispatcher dispatcher = new Dispatcher() {
            @Override
            public MockResponse dispatch(RecordedRequest request) throws InterruptedException {
                if (request.getPath().equals("/name")){
                    return new MockResponse().setResponseCode(200)
                            .setBody("JazzJackTheRabbit");
                }
                throw new IllegalStateException("no mock set up for " + request.getPath());
            }
        };
        return dispatcher;
    }

我建議將排程程式包裝在某種型別的 Builder 中，這樣你就可以輕鬆地為你的螢幕連結並新增新的響應。例如

 return newDispatcherBuilder()
            .withSerializedJSONBody("/authenticate", Mocks.getAuthenticationResponse())
            .withSerializedJSONBody("/getUserInfo", Mocks.getUserInfo())
            .withSerializedJSONBody("/checkNotBot", Mocks.checkNotBot());