WebSocket message event origin attribute test (Blob message)
On success, you will see a series of "PASS" messages, followed by "TEST COMPLETE".
PASS PASS: Message #0.
PASS origin is "ws://127.0.0.1:8880"
PASS PASS: Message #1.
PASS origin is "ws://127.0.0.1:8880"
PASS PASS: Message #2.
PASS origin is "ws://127.0.0.1:8880"
PASS closeEvent.wasClean is true
PASS successfullyParsed is true
TEST COMPLETE