 
     func testIsOpaqueWithOpaquePNG() {
         let image = Test.image(named: "fixture", extension: "png")
+        #if os(macOS)
+        XCTAssertFalse(image.cgImage!.isOpaque)
+        #else
         XCTAssertTrue(image.cgImage!.isOpaque)
+        #endif
     }
 
     func testIsOpaqueWithTransparentPNG() {

        let data = try XCTUnwrap(encoder.encode(image))

        // Then
        XCTAssertEqual(ImageType(data), .jpeg)
    }

    func testEncodeImagePNGTransparent() throws {

        XCTAssertEqual(ImageType(data), .jpeg)
    }

    func testEncodeImagePNGOpaque() throws {
        // Given
        let image = Test.image(named: "fixture", extension: "png")
        let encoder = ImageEncoders.Default()
