Add Basic Junit Tests to some plugins

packages/google_sign_in/google_sign_in/android/build.gradle

@@ -36,4 +36,6 @@ android {
 dependencies {
     implementation 'com.google.android.gms:play-services-auth:16.0.1'
     implementation 'com.google.guava:guava:20.0'
+    testImplementation 'junit:junit:4.12'
+    testImplementation 'org.mockito:mockito-inline:3.9.0'
 }

packages/google_sign_in/google_sign_in/android/src/test/java/io/flutter/plugins/googlesignin/GoogleSignInTest.java

@@ -0,0 +1,23 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package io.flutter.plugins.googlesignin;
+
+import static org.mockito.Mockito.mock;
+
+import android.content.Context;
+import io.flutter.plugin.common.BinaryMessenger;
+import io.flutter.plugin.common.MethodCall;
+import org.junit.Test;
+
+public class GoogleSignInTest {
+  @Test(expected = IllegalStateException.class)
+  public void signInThrowsWithoutActivity() {
+    final GoogleSignInPlugin plugin = new GoogleSignInPlugin();
+    plugin.initInstance(
+        mock(BinaryMessenger.class), mock(Context.class), mock(GoogleSignInWrapper.class));
+
+    plugin.onMethodCall(new MethodCall("signIn", null), null);
+  }
+}

packages/local_auth/android/build.gradle

@@ -37,6 +37,8 @@ dependencies {
     api "androidx.core:core:1.3.2"
     api "androidx.biometric:biometric:1.1.0"
     api "androidx.fragment:fragment:1.3.2"
+    testImplementation 'junit:junit:4.12'
+    testImplementation 'org.mockito:mockito-inline:3.9.0'
     androidTestImplementation 'androidx.test:runner:1.2.0'
     androidTestImplementation 'androidx.test:rules:1.2.0'
     androidTestImplementation 'androidx.test.espresso:espresso-core:3.2.0'

packages/local_auth/android/src/test/java/io/flutter/plugins/localauth/LocalAuthTest.java

@@ -0,0 +1,22 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package io.flutter.plugins.localauth;
+
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+
+import io.flutter.plugin.common.MethodCall;
+import io.flutter.plugin.common.MethodChannel;
+import org.junit.Test;
+
+public class LocalAuthTest {
+  @Test
+  public void isDeviceSupportedReturnsFalse() {
+    final LocalAuthPlugin plugin = new LocalAuthPlugin();
+    final MethodChannel.Result mockResult = mock(MethodChannel.Result.class);
+    plugin.onMethodCall(new MethodCall("isDeviceSupported", null), mockResult);
+    verify(mockResult).success(false);
+  }
+}

packages/shared_preferences/shared_preferences/android/build.gradle

@@ -39,4 +39,8 @@ android {
     lintOptions {
         disable 'InvalidPackage'
     }
+    dependencies {
+        testImplementation 'junit:junit:4.12'
+        testImplementation 'org.mockito:mockito-inline:3.9.0'
+    }
 }

packages/shared_preferences/shared_preferences/android/src/test/java/io/flutter/plugins/sharedpreferences/SharedPreferencesTest.java

@@ -0,0 +1,15 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package io.flutter.plugins.sharedpreferences;
+
+import org.junit.Test;
+
+public class SharedPreferencesTest {
+  // This is only a placeholder test and doesn't actually initialize the plugin.
+  @Test
+  public void initPluginDoesNotThrow() {
+    final SharedPreferencesPlugin plugin = new SharedPreferencesPlugin();
+  }
+}

packages/video_player/video_player/android/build.gradle

@@ -54,5 +54,7 @@ android {
         implementation 'com.google.android.exoplayer:exoplayer-hls:2.12.1'
         implementation 'com.google.android.exoplayer:exoplayer-dash:2.12.1'
         implementation 'com.google.android.exoplayer:exoplayer-smoothstreaming:2.12.1'
+        testImplementation 'junit:junit:4.12'
+        testImplementation 'org.mockito:mockito-inline:3.9.0'
     }
 }

packages/video_player/video_player/android/src/test/java/io/flutter/plugins/videoplayer/VideoPlayerTest.java

@@ -0,0 +1,15 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package io.flutter.plugins.videoplayer;
+
+import org.junit.Test;
+
+public class VideoPlayerTest {
+  // This is only a placeholder test and doesn't actually initialize the plugin.
+  @Test
+  public void initPluginDoesNotThrow() {
+    final VideoPlayerPlugin plugin = new VideoPlayerPlugin();
+  }
+}

packages/webview_flutter/android/build.gradle

@@ -36,5 +36,6 @@ android {
     dependencies {
         implementation 'androidx.annotation:annotation:1.0.0'
         implementation 'androidx.webkit:webkit:1.0.0'
+        testImplementation 'junit:junit:4.12'
     }
 }

packages/webview_flutter/android/src/main/java/io/flutter/plugins/webviewflutter/FlutterWebViewClient.java

@@ -36,7 +36,7 @@ class FlutterWebViewClient {
     this.methodChannel = methodChannel;
   }
 
-  private static String errorCodeToString(int errorCode) {
+  static String errorCodeToString(int errorCode) {
     switch (errorCode) {
       case WebViewClient.ERROR_AUTHENTICATION:
         return "authentication";

packages/webview_flutter/android/src/test/java/io/flutter/plugins/webviewflutter/WebViewTest.java

@@ -0,0 +1,49 @@
+// Copyright 2013 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package io.flutter.plugins.webviewflutter;
+
+import static org.junit.Assert.assertEquals;
+
+import android.webkit.WebViewClient;
+import org.junit.Test;
+
+public class WebViewTest {
+  @Test
+  public void errorCodes() {
+    assertEquals(
+        FlutterWebViewClient.errorCodeToString(WebViewClient.ERROR_AUTHENTICATION),
+        "authentication");
+    assertEquals(FlutterWebViewClient.errorCodeToString(WebViewClient.ERROR_BAD_URL), "badUrl");
+    assertEquals(FlutterWebViewClient.errorCodeToString(WebViewClient.ERROR_CONNECT), "connect");
+    assertEquals(
+        FlutterWebViewClient.errorCodeToString(WebViewClient.ERROR_FAILED_SSL_HANDSHAKE),
+        "failedSslHandshake");
+    assertEquals(FlutterWebViewClient.errorCodeToString(WebViewClient.ERROR_FILE), "file");
+    assertEquals(
+        FlutterWebViewClient.errorCodeToString(WebViewClient.ERROR_FILE_NOT_FOUND), "fileNotFound");
+    assertEquals(
+        FlutterWebViewClient.errorCodeToString(WebViewClient.ERROR_HOST_LOOKUP), "hostLookup");
+    assertEquals(FlutterWebViewClient.errorCodeToString(WebViewClient.ERROR_IO), "io");
+    assertEquals(
+        FlutterWebViewClient.errorCodeToString(WebViewClient.ERROR_PROXY_AUTHENTICATION),
+        "proxyAuthentication");
+    assertEquals(
+        FlutterWebViewClient.errorCodeToString(WebViewClient.ERROR_REDIRECT_LOOP), "redirectLoop");
+    assertEquals(FlutterWebViewClient.errorCodeToString(WebViewClient.ERROR_TIMEOUT), "timeout");
+    assertEquals(
+        FlutterWebViewClient.errorCodeToString(WebViewClient.ERROR_TOO_MANY_REQUESTS),
+        "tooManyRequests");
+    assertEquals(FlutterWebViewClient.errorCodeToString(WebViewClient.ERROR_UNKNOWN), "unknown");
+    assertEquals(
+        FlutterWebViewClient.errorCodeToString(WebViewClient.ERROR_UNSAFE_RESOURCE),
+        "unsafeResource");
+    assertEquals(
+        FlutterWebViewClient.errorCodeToString(WebViewClient.ERROR_UNSUPPORTED_AUTH_SCHEME),
+        "unsupportedAuthScheme");
+    assertEquals(
+        FlutterWebViewClient.errorCodeToString(WebViewClient.ERROR_UNSUPPORTED_SCHEME),
+        "unsupportedScheme");
+  }
+}