Minor unit test updates

Author: orchetect

Tests/TimecodeKit-Unit-Tests/Unit Tests/Utilities/Fraction Tests.swift

@@ -68,13 +68,19 @@ class Fraction_Tests: XCTestCase {
         XCTAssertEqual(Fraction(1, 2) + Fraction(1, 4), Fraction(3, 4))
         XCTAssertEqual(Fraction(2, 4) + Fraction(1, 4), Fraction(3, 4))
 
+        XCTAssertEqual(Fraction(-1, 2) + Fraction(1, 4), Fraction(-1, 4))
+        XCTAssertEqual(Fraction(-1, 2) + Fraction(-1, 4), Fraction(-3, 4))
+        
         XCTAssertEqual(Fraction(750, 1900) + Fraction(8000, 3800), Fraction(5, 2))
     }
 
     func testMathSubtract() {
         XCTAssertEqual(Fraction(3, 4) - Fraction(1, 2), Fraction(1, 4))
         XCTAssertEqual(Fraction(3, 4) - Fraction(2, 4), Fraction(1, 4))
 
+        XCTAssertEqual(Fraction(-3, 4) - Fraction(2, 4), Fraction(-5, 4))
+        XCTAssertEqual(Fraction(-3, 4) - Fraction(-2, 4), Fraction(-1, 4))
+        
         XCTAssertEqual(Fraction(8000, 3800) - Fraction(100, 1900), Fraction(39, 19))
     }