if !reflect.DeepEqual(got, expected) {
		t.Errorf("split(%q): got %q expected %q", inLine, got, expected)
	}

	// Now change the value of $X and see if the recorded definition is
	// still intact (vs. having the $_X already substituted out)

	os.Setenv("_X", "Z")
	inLine = "//go:generate CMD0"
	expected = []string{"abZcd"}
	got = g.split(inLine + "\n")

	if !reflect.DeepEqual(got, expected) {