Finding file name of test that failed using go test (golang)

When a Go unit test fails "go test" will display a message like:

--- FAIL: TestFillDeepStruct (0.00s)

But what is the name of the file (in this case Deep_test.go) containing the failing test. I can find no option to "go test" to do this. I have many test files and it is tedious to grep for the test function name.