title: Clang Error: Reference to NSUTF8StringEncoding is ambiguous
body: <p>I am trying to create unit tests using the new XCTest framework introduced in Xcode 5. I have a line in one of my test cases that looks like this:</p>
  
  <p><code>XCTAssertEqual([self.client stringEncoding], NSUTF8StringEncoding, …);</code></p>
  
  <p>When I try to run my tests, Xcode spits out this error: "Reference to NSUTF8StringEncoding is ambiguous." I can get the test to work by changing the above line to this:</p>
  
  <p><code>XCTAssertEqual([self.client stringEncoding], (NSStringEncoding) 4, …);</code></p>
  
  <p>(This works because 4 is the value of <code>NSUTF8StringEncoding</code>.) This also happens when I assign <code>NSUTF8StringEncoding</code> to a local variable and use it in the <code>XCTAssertEqual()</code> call instead. Why am I getting this error?</p>