First tests

Author: simonesestito

.idea/runConfigurations/Run_all_JUnit_tests.xml

@@ -91,6 +91,9 @@ dependencies {
 
     // Testing libs
     testImplementation "junit:junit:$versions.junit"
+    testImplementation "org.mockito:mockito-core:$versions.mockito"
+    testImplementation "org.powermock:powermock-module-junit4:$versions.powermock"
+    testImplementation "org.powermock:powermock-api-mockito2:$versions.powermock"
     androidTestImplementation "androidx.test.ext:junit:$versions.junitExt"
     androidTestImplementation "androidx.test.espresso:espresso-core:$versions.espresso"
 }

app/build.gradle

@@ -25,12 +25,14 @@
 import java.lang.reflect.Type;
 import java.util.Objects;
 
+import okhttp3.internal.annotations.EverythingIsNonNull;
 import retrofit2.Call;
 import retrofit2.CallAdapter;
 import retrofit2.Callback;
 import retrofit2.Response;
 import retrofit2.Retrofit;
 
+@EverythingIsNonNull
 public class ApiCallAdapter<T> implements CallAdapter<T, ApiResponse<T>> {
     private final Type responseType;
 

app/src/main/java/com/simonesestito/shopsqueue/api/ApiCallAdapter.java

@@ -0,0 +1,80 @@
+/*
+ * Copyright 2020 Simone Sestito
+ * This file is part of Shops Queue.
+ *
+ * Shops Queue is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Shops Queue is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Shops Queue.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.simonesestito.shopsqueue;
+
+import android.os.Handler;
+import android.os.Looper;
+
+import org.mockito.stubbing.Answer;
+import org.powermock.api.mockito.PowerMockito;
+
+import java.util.concurrent.Executors;
+import java.util.concurrent.ScheduledExecutorService;
+import java.util.concurrent.TimeUnit;
+
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyLong;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.when;
+
+/**
+ * Utility methods that unit tests can use to do common android library mocking that might be needed.
+ * <p>
+ * Credits: https://gist.github.com/dpmedeiros/7f7724fdf13fc5390bb05958448cdcad
+ */
+public class AndroidMockUtil {
+    private final static ScheduledExecutorService mainThread = Executors.newSingleThreadScheduledExecutor();
+
+    private AndroidMockUtil() {
+    }
+
+    /**
+     * Mocks main thread handler post() and postDelayed() for use in Android unit tests
+     * <p>
+     * To use this:
+     * <ol>
+     *     <li>Call this method in an {@literal @}Before method of your test.</li>
+     *     <li>Place Looper.class in the {@literal @}PrepareForTest annotation before your test class.</li>
+     *     <li>any class under test that needs to call {@code new Handler(Looper.getMainLooper())} should be placed
+     *     in the {@literal @}PrepareForTest annotation as well.</li>
+     * </ol>
+     */
+    public static void mockMainThreadHandler() throws Exception {
+        PowerMockito.mockStatic(Looper.class);
+        Looper mockMainThreadLooper = mock(Looper.class);
+        when(Looper.getMainLooper()).thenReturn(mockMainThreadLooper);
+        Handler mockMainThreadHandler = mock(Handler.class);
+
+        Answer<Boolean> handlerPostAnswer = invocation -> {
+            Runnable runnable = invocation.getArgument(0, Runnable.class);
+            Long delay = 0L;
+            if (invocation.getArguments().length > 1) {
+                delay = invocation.getArgument(1, Long.class);
+            }
+            if (runnable != null) {
+                mainThread.schedule(runnable, delay, TimeUnit.MILLISECONDS);
+            }
+            return true;
+        };
+
+        when(mockMainThreadHandler.post(any(Runnable.class))).then(handlerPostAnswer);
+        when(mockMainThreadHandler.postDelayed(any(Runnable.class), anyLong())).then(handlerPostAnswer);
+        PowerMockito.whenNew(Handler.class).withArguments(mockMainThreadLooper).thenReturn(mockMainThreadHandler);
+    }
+}

app/src/test/java/com/simonesestito/shopsqueue/AndroidMockUtil.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2020 Simone Sestito
+ * This file is part of Shops Queue.
+ *
+ * Shops Queue is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * Shops Queue is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with Shops Queue.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+package com.simonesestito.shopsqueue.api;
+
+import android.os.Looper;
+
+import com.simonesestito.shopsqueue.AndroidMockUtil;
+import com.simonesestito.shopsqueue.util.functional.Callback;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mock;
+import org.powermock.core.classloader.annotations.PrepareForTest;
+import org.powermock.modules.junit4.PowerMockRunner;
+
+import static org.mockito.Mockito.verify;
+
+@RunWith(PowerMockRunner.class)
+@PrepareForTest(Looper.class)
+public class ApiResponseTest {
+    @Mock
+    public Callback<Object> callback;
+
+    @Before
+    public void mockMainThread() throws Exception {
+        AndroidMockUtil.mockMainThreadHandler();
+    }
+
+    @Test
+    public void onResultHandlerIsCalled() {
+        ApiResponse<Object> apiResponse = new ApiResponse<>();
+        apiResponse.onResult(callback);
+
+        Object result = new Object();
+        apiResponse.emitResult(result);
+
+        verify(callback).onResult(result);
+    }
+}

app/src/test/java/com/simonesestito/shopsqueue/ExampleUnitTest.java

@@ -41,5 +41,7 @@ versions.licensesLib = '17.0.0'
 versions.junit = '4.12'
 versions.junitExt = '1.1.1'
 versions.espresso = '3.2.0'
+versions.mockito = '3.3.3'
+versions.powermock = '2.0.2'
 
 ext.versions = versions