Added tests, added possible null values checks

Author: JDDV

lib/src/google_api_availability.dart

@@ -25,6 +25,9 @@ class GoogleApiAvailability {
   /// This feature is only available on Android devices. On any other platforms
   /// the [checkPlayServicesAvailability] method will always return
   /// [GooglePlayServicesAvailability.notAvailableOnPlatform].
+  ///
+  /// Returns the connection status of Google Play Service.
+  /// Optionally, you can also show an error dialog if the connection status is not [SUCCESS].
   Future<GooglePlayServicesAvailability> checkGooglePlayServicesAvailability(
       [bool showDialogIfNecessary = false]) async {
     if (defaultTargetPlatform != TargetPlatform.android) {
@@ -55,6 +58,10 @@ class GoogleApiAvailability {
     final availability =
         await _methodChannel.invokeMethod('makeGooglePlayServicesAvailable');
 
+    if (availability == null) {
+      return false;
+    }
+
     return availability;
   }
 
@@ -67,6 +74,10 @@ class GoogleApiAvailability {
 
     final errorString = await _methodChannel.invokeMethod('getErrorString');
 
+    if (errorString == null) {
+      return "ErrorString is null";
+    }
+
     return errorString;
   }
 
@@ -81,6 +92,10 @@ class GoogleApiAvailability {
     final isUserResolvable =
         await _methodChannel.invokeMethod('isUserResolvable');
 
+    if (isUserResolvable == null) {
+      return false;
+    }
+
     return isUserResolvable;
   }
 
@@ -99,6 +114,10 @@ class GoogleApiAvailability {
     final showErrorNotification =
         await _methodChannel.invokeMethod('showErrorNotification');
 
+    if (showErrorNotification == null) {
+      return false;
+    }
+
     return showErrorNotification;
   }
 }

test/google_api_availability_test.dart

@@ -71,6 +71,25 @@ void main() {
       debugDefaultTargetPlatformOverride = null;
     });
 
+    test(
+        'Should receive false when availability is null',
+            () async {
+          const availability = null;
+
+          MethodChannelMock(
+            channelName: 'flutter.baseflow.com/google_api_availability/methods',
+            method: 'makeGooglePlayServicesAvailable',
+            result: availability,
+          );
+
+          final googlePlayServiceAvailability =
+          await const GoogleApiAvailability.private()
+              .makeGooglePlayServicesAvailable();
+
+          expect(googlePlayServiceAvailability,
+              false);
+        });
+
     test(
         'Should receive true when device is able to set Google Play Services to available',
         () async {
@@ -104,6 +123,25 @@ void main() {
       debugDefaultTargetPlatformOverride = null;
     });
 
+    test(
+        'Should receive "ErrorString is null" when availability is null',
+            () async {
+          const errorString = null;
+
+          MethodChannelMock(
+            channelName: 'flutter.baseflow.com/google_api_availability/methods',
+            method: 'getErrorString',
+            result: errorString,
+          );
+
+          final errorStringResult =
+          await const GoogleApiAvailability.private()
+              .getErrorString();
+
+          expect(errorStringResult,
+              "ErrorString is null");
+        });
+
     test('Should receive SUCCESS when connection status is success', () async {
       MethodChannelMock(
         channelName: 'flutter.baseflow.com/google_api_availability/methods',
@@ -130,6 +168,25 @@ void main() {
       debugDefaultTargetPlatformOverride = null;
     });
 
+    test(
+        'Should receive false when isUserResolvable is null',
+            () async {
+          const isUserResolvable = null;
+
+          MethodChannelMock(
+            channelName: 'flutter.baseflow.com/google_api_availability/methods',
+            method: 'isUserResolvable',
+            result: isUserResolvable,
+          );
+
+          final isUserResolvableResult =
+          await const GoogleApiAvailability.private()
+              .isUserResolvable();
+
+          expect(isUserResolvableResult,
+              false);
+        });
+
     test('Should receive true when error is user resolvable', () async {
       MethodChannelMock(
         channelName: 'flutter.baseflow.com/google_api_availability/methods',
@@ -156,6 +213,25 @@ void main() {
       debugDefaultTargetPlatformOverride = null;
     });
 
+    test(
+        'Should receive false when showErrorNotification is null',
+            () async {
+          const showErrorNotification = null;
+
+          MethodChannelMock(
+            channelName: 'flutter.baseflow.com/google_api_availability/methods',
+            method: 'showErrorNotification',
+            result: showErrorNotification,
+          );
+
+          final showErrorNotificationResult =
+          await const GoogleApiAvailability.private()
+              .showErrorNotification();
+
+          expect(showErrorNotificationResult,
+              false);
+        });
+
     test('Should receive true when notification is shown', () async {
       MethodChannelMock(
         channelName: 'flutter.baseflow.com/google_api_availability/methods',