Simple test for regression

Author: johnno1962

TestFoundation/TestNSDictionary.swift

@@ -32,6 +32,7 @@ class TestNSDictionary : XCTestCase {
             ("test_mutableCopying", test_mutableCopying),
             ("test_writeToFile", test_writeToFile),
             ("test_initWithContentsOfFile", test_initWithContentsOfFile),
+            ("test_settingWithStringKey", test_settingWithStringKey),
         ]
     }
 
@@ -222,6 +223,12 @@ class TestNSDictionary : XCTestCase {
         }
     }
 
+    func test_settingWithStringKey() {
+        let dict = NSDictionary()
+        // has crashed in the past
+        dict["stringKey"] = "value"
+    }
+
     private func createTestFile(_ path: String, _contents: Data) -> String? {
         let tempDir = NSTemporaryDirectory() + "TestFoundation_Playground_" + NSUUID().uuidString + "/"
         do {