1 Test the handling of negative sourceRect offset in getImageData().
3 On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
11 PASS imgdata[61] is 128
13 PASS imgdata[63] is 255
14 PASS imgdata[64] is 255
17 PASS imgdata[67] is 255
18 PASS successfullyParsed is true