Updates tests to check for Swift 4.2.

Updates build settings to use Swift 4.2.

Author: laurentaylormarshall

Comb Sort/Tests/CombSortTests.swift

@@ -12,9 +12,9 @@ class CombSortTests: XCTestCase {
     var sequence: [Int]!
     let expectedSequence: [Int] = [-12, -10, -1, 2, 9, 32, 55, 67, 89, 101]
 
-    func testSwift4(){
-        #if swift(>=4.0)
-            print("Hello, Swift 4!")
+    func testSwiftVersion(){
+        #if swift(>=4.2)
+            print("Hello, Swift 4.2!")
         #endif
     }
 

Comb Sort/Tests/Tests.xcodeproj/project.pbxproj

@@ -187,7 +187,7 @@
 				SDKROOT = macosx;
 				SWIFT_ACTIVE_COMPILATION_CONDITIONS = DEBUG;
 				SWIFT_OPTIMIZATION_LEVEL = "-Onone";
-				SWIFT_VERSION = 4.0;
+				SWIFT_VERSION = 4.2;
 			};
 			name = Debug;
 		};
@@ -237,7 +237,7 @@
 				MTL_ENABLE_DEBUG_INFO = NO;
 				SDKROOT = macosx;
 				SWIFT_OPTIMIZATION_LEVEL = "-Owholemodule";
-				SWIFT_VERSION = 4.0;
+				SWIFT_VERSION = 4.2;
 			};
 			name = Release;
 		};