On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
-PASS ctx.createImageData(null) threw exception NotSupportedError: Failed to execute 'createImageData' on 'CanvasRenderingContext2D': The 1st argument provided is either null, or an invalid ImageData object..
+PASS ctx.createImageData(null) threw exception TypeError: Failed to execute 'createImageData' on 'CanvasRenderingContext2D': No function was found that matched the signature provided..
PASS imageData.width is 100
PASS imageData.height is 50
PASS imageData.data[32] is 255