1 files changed, 60 insertions, 0 deletions
diff --git a/Firestore/core/test/firebase/firestore/util/string_format_apple_test.mm b/Firestore/core/test/firebase/firestore/util/string_format_apple_test.mm
new file mode 100644
index 0000000..f0bcd35
--- /dev/null
+++ b/Firestore/core/test/firebase/firestore/util/string_format_apple_test.mm
@@ -0,0 +1,60 @@
+/*
+ * Copyright 2018 Google
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "Firestore/core/src/firebase/firestore/util/string_format.h"
+
+#import <Foundation/NSString.h>
+
+#include "gtest/gtest.h"
+
+@interface FSTDescribable : NSObject
+@end
+
+@implementation FSTDescribable
+
+- (NSString*)description {
+  return @"description";
+}
+
+@end
+
+namespace firebase {
+namespace firestore {
+namespace util {
+
+TEST(StringFormatTest, NSString) {
+  EXPECT_EQ("Hello World", StringFormat("Hello %s", @"World"));
+
+  NSString* hello = [NSString stringWithUTF8String:"Hello"];
+  EXPECT_EQ("Hello World", StringFormat("%s World", hello));
+
+  // NOLINTNEXTLINE false positive on "string"
+  NSMutableString* world = [NSMutableString string];
+  [world appendString:@"World"];
+  EXPECT_EQ("Hello World", StringFormat("Hello %s", world));
+}
+
+TEST(StringFormatTest, FSTDescribable) {
+  FSTDescribable* desc = [[FSTDescribable alloc] init];
+  EXPECT_EQ("Hello description", StringFormat("Hello %s", desc));
+
+  id desc_id = desc;
+  EXPECT_EQ("Hello description", StringFormat("Hello %s", desc_id));
+}
+
+}  //  namespace util
+}  //  namespace firestore
+}  //  namespace firebase