[tests] Add unit test for style loading failures

test/map/map.cpp

@@ -60,11 +60,20 @@ TEST(Map, SetStyleInvalidJSON) {
 
     Log::setObserver(std::make_unique<FixtureLogObserver>());
 
+    bool fail = false;
+    test.view.setMapChangeCallback([&](MapChange change) {
+        if (change == mbgl::MapChangeDidFailLoadingMap) {
+            fail = true;
+        }
+    });
+
     {
         Map map(test.view, test.fileSource, MapMode::Still);
         map.setStyleJSON("invalid");
     }
 
+    EXPECT_TRUE(fail);
+
     auto observer = Log::removeObserver();
     auto flo = dynamic_cast<FixtureLogObserver*>(observer.get());
     EXPECT_EQ(1u, flo->count({ EventSeverity::Error, Event::ParseStyle, -1,
@@ -73,6 +82,29 @@ TEST(Map, SetStyleInvalidJSON) {
     EXPECT_TRUE(unchecked.empty()) << unchecked;
 }
 
+TEST(Map, SetStyleInvalidURL) {
+    MapTest test;
+
+    test.fileSource.styleResponse = [] (const Resource&) {
+        Response response;
+        response.error = std::make_unique<Response::Error>(
+            Response::Error::Reason::Other,
+            "Failed by the test case");
+        return response;
+    };
+
+    test.view.setMapChangeCallback([&](MapChange change) {
+        if (change == mbgl::MapChangeDidFailLoadingMap) {
+            test.runLoop.stop();
+        }
+    });
+
+    Map map(test.view, test.fileSource, MapMode::Still);
+    map.setStyleURL("mapbox://bar");
+
+    test.runLoop.run();
+}
+
 TEST(Map, DoubleStyleLoad) {
     MapTest test;