package main import ( "testing" ) func TestInvalidIP(t *testing.T) { _, err := generateJSON("foo") errwant := "invalid IP" if err.Error() != errwant { t.Fatalf(`generateJSON("foo") == "%v", wants "%s"`, err, errwant) } } func TestInaccessibleIP(t *testing.T) { _, err := generateJSON("0.0.0.0") errwant := "unspecified IP" if err.Error() != errwant { t.Fatalf(`generateJSON("0.0.0.0") == "%v", wants "%s"`, err, errwant) } }