New expectation functions plus convert old tests to use these.

tests/dom/canvas_test.dart

 #library('CanvasTest');
 #import('../../lib/unittest/unittest.dart');
 #import('../../lib/unittest/dom_config.dart');
 #import('dart:dom_deprecated');
 
 main() {
   HTMLCanvasElement canvas;
   CanvasRenderingContext2D context;
   int width = 100;
   int height = 100;
@@ skipping 16 matching lines @@
     checkPixel(data, 10 + width * 10, [255, 0, 0, 255]);
     checkPixel(data, 29 + width * 10, [255, 0, 0, 255]);
     checkPixel(data, 30 + width * 10, [0, 0, 0, 0]);
   });
   test('FillStyleGradient', () {
     var gradient = context.createLinearGradient(0,0,20,20);
     gradient.addColorStop(0,'red');
     gradient.addColorStop(1,'blue');
     context.fillStyle = gradient;
     context.fillRect(0, 0, 20, 20);
-    expect(context.fillStyle is CanvasGradient).isTrue();
+    expect(context.fillStyle is CanvasGradient, isTrue);
   });
   test('SetFillColor', () {
     // With floats.
     context.setFillColor(10, 10, 10, 10);
     context.fillRect(10, 10, 20, 20);
 
     // With rationals.
     context.setFillColor(10.0, 10.0, 10.0, 10.0);
     context.fillRect(20, 20, 30, 30);
 
@@ skipping 33 matching lines @@
   });
 }
 
 void checkPixel(Uint8ClampedArray data, int offset, List<int> rgba)
 {
   offset *= 4;
   for (var i = 0; i < 4; ++i) {
     Expect.equals(rgba[i], data[offset + i]);
   }
 }