Support Promise-based async tests from Xcode tests

We already supported this for React Native and Node test runners. Now we support returning promises from tests everywhere.

tests/ios/RJSModuleLoader.h

@@ -27,5 +27,6 @@
 
 - (JSValue *)loadModuleFromURL:(NSURL *)url error:(NSError **)error;
 - (JSValue *)loadJSONFromURL:(NSURL *)url error:(NSError **)error;
+- (JSValue *)loadGlobalModule:(NSString *)name relativeToURL:(NSURL *)url error:(NSError **)error;
 
 @end

tests/ios/RJSModuleLoader.m

@@ -195,6 +195,18 @@ static NSString * const RJSModuleLoaderErrorDomain = @"RJSModuleLoaderErrorDomai
         BOOL isDirectory;
 
         if ([fileManager fileExistsAtPath:moduleURL.path isDirectory:&isDirectory] && isDirectory) {
+            NSURL *packageURL = [moduleURL URLByAppendingPathComponent:@"package.json"];
+            NSDictionary *package;
+
+            if ([fileManager fileExistsAtPath:packageURL.path]) {
+                NSError *error;
+                NSData *data = [NSData dataWithContentsOfURL:packageURL options:0 error:&error];
+
+                package = data ? [NSJSONSerialization JSONObjectWithData:data options:0 error:&error] : nil;
+                NSAssert(package, @"%@", error);
+            }
+
+            moduleURL = [moduleURL URLByAppendingPathComponent:package[@"main"] ?: @"index.js"];
             return [self loadModuleFromURL:moduleURL error:error];
         }
 

tests/ios/RealmJSCoreTests.m

@@ -31,12 +31,23 @@
 
 + (XCTestSuite *)defaultTestSuite {
     XCTestSuite *suite = [super defaultTestSuite];
-    JSContext *context = [[JSContext alloc] init];
+
+    // We need a JS context from a UIWebView so it has setTimeout, Promise, etc.
+    UIWebView *webView = [[UIWebView alloc] init];
+    JSContext *context = [webView valueForKeyPath:@"documentView.webView.mainFrame.javaScriptContext"];
     RJSModuleLoader *moduleLoader = [[RJSModuleLoader alloc] initWithContext:context];
     NSURL *realmURL = [[NSBundle bundleForClass:self] URLForResource:@"index" withExtension:@"js" subdirectory:@"lib"];
     NSURL *scriptURL = [[NSBundle bundleForClass:self] URLForResource:@"index" withExtension:@"js" subdirectory:@"js"];
     NSError *error;
 
+    // The ES6 global Promise constructor was added in iOS 8.
+    if (![context[@"Promise"] isObject]) {
+        JSValue *promiseModule = [moduleLoader loadGlobalModule:@"es6-promise" relativeToURL:scriptURL error:&error];
+        NSAssert(promiseModule, @"%@", error);
+
+        context[@"Promise"] = promiseModule[@"Promise"];
+    }
+
     // Create Realm constructor in the JS context.
     RJSInitializeInContext(context.JSGlobalContextRef);
 
@@ -73,10 +84,32 @@
     JSContext *context = testObject.context;
     context.exception = nil;
 
-    [testObject invokeMethod:@"runTest" withArguments:@[NSStringFromClass(self.class), method]];
+    JSValue *promise = [testObject invokeMethod:@"runTest" withArguments:@[NSStringFromClass(self.class), method]];
 
-    JSValue *exception = context.exception;
-    if (exception) {
+    if (context.exception) {
+        [self recordException:context.exception];
+        return;
+    }
+
+    if ([promise isObject]) {
+        XCTestExpectation *expectation = [self expectationWithDescription:@"Promise resolved or rejected"];
+
+        JSValue *onFulfilled = [JSValue valueWithObject:^() {
+            [expectation fulfill];
+        } inContext:context];
+
+        JSValue *onRejected = [JSValue valueWithObject:^(JSValue *error) {
+            [self recordException:error];
+            [expectation fulfill];
+        } inContext:context];
+
+        [promise invokeMethod:@"then" withArguments:@[onFulfilled, onRejected]];
+
+        [self waitForExpectationsWithTimeout:5.0 handler:NULL];
+    }
+}
+
+- (void)recordException:(JSValue *)exception {
     JSValue *message = [exception hasProperty:@"message"] ? exception[@"message"] : exception;
     NSString *source = [exception hasProperty:@"sourceURL"] ? [exception[@"sourceURL"] toString] : nil;
     NSUInteger line = [exception hasProperty:@"line"] ? [exception[@"line"] toUInt32] - 1 : 0;
@@ -92,6 +125,5 @@
                                 atLine:sourceURL ? line : __LINE__
                               expected:YES];
 }
-}
 
 @end

tests/js/package.json

@@ -1,5 +1,8 @@
 {
   "name": "realm-tests",
   "version": "0.0.1",
-  "private": true
+  "private": true,
+  "dependencies": {
+    "es6-promise": "^3.2.1"
+  }
 }