Add unit tests for AppOpenAdManager behavior

app/src/test/java/com/d4rk/androidtutorials/java/ads/managers/AppOpenAdManagerTest.java

@@ -0,0 +1,170 @@
+package com.d4rk.androidtutorials.java.ads.managers;
+
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyString;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.mockStatic;
+import static org.mockito.Mockito.times;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import android.app.Activity;
+import android.app.Application;
+import android.content.Context;
+
+import com.d4rk.androidtutorials.java.ads.AdUtils;
+import com.d4rk.androidtutorials.java.ads.managers.AppOpenAd.OnShowAdCompleteListener;
+import com.google.android.gms.ads.AdRequest;
+import com.google.android.gms.ads.FullScreenContentCallback;
+import com.google.android.gms.ads.appopen.AppOpenAd.AppOpenAdLoadCallback;
+
+import org.junit.Before;
+import org.junit.Test;
+import org.mockito.ArgumentCaptor;
+import org.mockito.MockedStatic;
+
+import java.lang.reflect.Constructor;
+import java.lang.reflect.Field;
+import java.lang.reflect.Method;
+import java.util.concurrent.TimeUnit;
+
+/**
+ * Unit tests for {@link AppOpenAd.AppOpenAdManager}.
+ */
+public class AppOpenAdManagerTest {
+
+    private Class<?> managerClass;
+    private Object manager;
+    private Application application;
+
+    @Before
+    public void setUp() throws Exception {
+        application = mock(Application.class);
+        when(application.getApplicationContext()).thenReturn(application);
+
+        managerClass = findManagerClass();
+        Constructor<?> constructor = managerClass.getDeclaredConstructor(Application.class);
+        constructor.setAccessible(true);
+        manager = constructor.newInstance(application);
+    }
+
+    @Test
+    public void isAdAvailable_returnsFalseWhenAdIsNull() throws Exception {
+        setField("appOpenAd", null);
+        setLongField("loadTime", System.currentTimeMillis());
+
+        assertFalse(invokeIsAdAvailable());
+    }
+
+    @Test
+    public void isAdAvailable_returnsFalseWhenLoadTimeTooOld() throws Exception {
+        com.google.android.gms.ads.appopen.AppOpenAd ad = mock(com.google.android.gms.ads.appopen.AppOpenAd.class);
+        setField("appOpenAd", ad);
+        long staleTime = System.currentTimeMillis() - TimeUnit.HOURS.toMillis(5);
+        setLongField("loadTime", staleTime);
+
+        assertFalse(invokeIsAdAvailable());
+    }
+
+    @Test
+    public void isAdAvailable_returnsTrueWhenAdFresh() throws Exception {
+        com.google.android.gms.ads.appopen.AppOpenAd ad = mock(com.google.android.gms.ads.appopen.AppOpenAd.class);
+        setField("appOpenAd", ad);
+        long recentTime = System.currentTimeMillis() - TimeUnit.HOURS.toMillis(1);
+        setLongField("loadTime", recentTime);
+
+        assertTrue(invokeIsAdAvailable());
+    }
+
+    @Test
+    public void showAdIfAvailable_withoutAd_loadsNewAd() throws Exception {
+        Activity activity = mock(Activity.class);
+        OnShowAdCompleteListener listener = mock(OnShowAdCompleteListener.class);
+
+        try (MockedStatic<AdUtils> adUtils = mockStatic(AdUtils.class);
+             MockedStatic<com.google.android.gms.ads.appopen.AppOpenAd> appOpenAdStatic =
+                     mockStatic(com.google.android.gms.ads.appopen.AppOpenAd.class)) {
+            com.google.android.gms.ads.appopen.AppOpenAd loadedAd = mock(com.google.android.gms.ads.appopen.AppOpenAd.class);
+
+            appOpenAdStatic
+                    .when(() -> com.google.android.gms.ads.appopen.AppOpenAd.load(
+                            any(Context.class),
+                            anyString(),
+                            any(AdRequest.class),
+                            any(AppOpenAdLoadCallback.class)))
+                    .thenAnswer(invocation -> {
+                        AppOpenAdLoadCallback callback = invocation.getArgument(3);
+                        callback.onAdLoaded(loadedAd);
+                        return null;
+                    });
+
+            invokeShowAdIfAvailable(activity, listener);
+
+            adUtils.verify(() -> AdUtils.initialize(any(Context.class)));
+            appOpenAdStatic.verify(() -> com.google.android.gms.ads.appopen.AppOpenAd.load(
+                    any(Context.class),
+                    anyString(),
+                    any(AdRequest.class),
+                    any(AppOpenAdLoadCallback.class)));
+        }
+
+        verify(listener, times(1)).onShowAdComplete();
+    }
+
+    @Test
+    public void showAdIfAvailable_withAd_doesNotShowTwiceWhileShowing() throws Exception {
+        Activity activity = mock(Activity.class);
+        OnShowAdCompleteListener listener = mock(OnShowAdCompleteListener.class);
+        com.google.android.gms.ads.appopen.AppOpenAd ad = mock(com.google.android.gms.ads.appopen.AppOpenAd.class);
+
+        setField("appOpenAd", ad);
+        setLongField("loadTime", System.currentTimeMillis());
+
+        invokeShowAdIfAvailable(activity, listener);
+        invokeShowAdIfAvailable(activity, listener);
+
+        ArgumentCaptor<FullScreenContentCallback> callbackCaptor =
+                ArgumentCaptor.forClass(FullScreenContentCallback.class);
+        verify(ad, times(1)).setFullScreenContentCallback(callbackCaptor.capture());
+        verify(ad, times(1)).show(activity);
+    }
+
+    private Class<?> findManagerClass() {
+        for (Class<?> clazz : AppOpenAd.class.getDeclaredClasses()) {
+            if ("AppOpenAdManager".equals(clazz.getSimpleName())) {
+                return clazz;
+            }
+        }
+        throw new IllegalStateException("AppOpenAdManager class not found");
+    }
+
+    private boolean invokeIsAdAvailable() throws Exception {
+        Method method = managerClass.getDeclaredMethod("isAdAvailable");
+        method.setAccessible(true);
+        return (boolean) method.invoke(manager);
+    }
+
+    private void invokeShowAdIfAvailable(Activity activity, OnShowAdCompleteListener listener)
+            throws Exception {
+        Method method = managerClass.getDeclaredMethod(
+                "showAdIfAvailable",
+                Activity.class,
+                OnShowAdCompleteListener.class);
+        method.setAccessible(true);
+        method.invoke(manager, activity, listener);
+    }
+
+    private void setField(String fieldName, Object value) throws Exception {
+        Field field = managerClass.getDeclaredField(fieldName);
+        field.setAccessible(true);
+        field.set(manager, value);
+    }
+
+    private void setLongField(String fieldName, long value) throws Exception {
+        Field field = managerClass.getDeclaredField(fieldName);
+        field.setAccessible(true);
+        field.setLong(manager, value);
+    }
+}