Add Testing to uikit.

Summary: I'm going to make some changes, but first, I want to get testing setup.

Reviewed By: rnystrom

Differential Revision: D4022585

fbshipit-source-id: a48516faad0bcb1a9cf5610ab21da5ee099c6f16

uikit/CSSLayout/Tests/CSSLayoutTests.m

@@ -0,0 +1,26 @@
+/**
+ * Copyright (c) 2014-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import <XCTest/XCTest.h>
+
+#import "UIView+CSSLayout.h"
+
+@interface CSSLayoutTests : XCTestCase
+@end
+
+@implementation CSSLayoutTests
+
+- (void)testSmoke
+{
+  UIView *view = [[UIView alloc] initWithFrame:CGRectZero];
+  [view css_setUsesFlexbox:YES];
+  XCTAssertTrue([view css_usesFlexbox]);
+}
+
+@end