package utils import ( "fmt" "os" "os/exec" "strings" "testing" ) var traefikBinary = "traefik" func TestRunCommand(t *testing.T) { // Override exec.Command :D execCommand = fakeExecCommand _, output, err := RunCommand(traefikBinary, "it", "works") if err != nil { t.Fatal(err) } if output != "it works" { t.Fatalf("Expected 'it works' as output, got : %q", output) } } func TestRunCommandError(t *testing.T) { // Override exec.Command :D execCommand = fakeExecCommand _, output, err := RunCommand(traefikBinary, "an", "error") if err == nil { t.Fatalf("Expected an error, got %q", output) } } // Helpers :) // Type implementing the io.Writer interface for analyzing output. type String struct { value string } // The only function required by the io.Writer interface. Will append // written data to the String.value string. func (s *String) Write(p []byte) (n int, err error) { s.value += string(p) return len(p), nil } // Helper function that mock the exec.Command call (and call the test binary) func fakeExecCommand(command string, args ...string) *exec.Cmd { cs := []string{"-test.run=TestHelperProcess", "--", command} cs = append(cs, args...) cmd := exec.Command(os.Args[0], cs...) cmd.Env = []string{"GO_WANT_HELPER_PROCESS=1"} return cmd } func TestHelperProcess(t *testing.T) { if os.Getenv("GO_WANT_HELPER_PROCESS") != "1" { return } args := os.Args // Previous arguments are tests stuff, that looks like : // /tmp/go-build970079519/…/_test/integration.test -test.run=TestHelperProcess -- cmd, args := args[3], args[4:] // Handle the case where args[0] is dir:... switch cmd { case traefikBinary: argsStr := strings.Join(args, " ") switch argsStr { case "an exitCode 127": fmt.Fprint(os.Stderr, "an error has occurred with exitCode 127") os.Exit(127) case "an error": fmt.Fprint(os.Stderr, "an error has occurred") os.Exit(1) case "it works": fmt.Fprint(os.Stdout, "it works") default: fmt.Fprint(os.Stdout, "no arguments") } default: fmt.Fprintf(os.Stderr, "Command %s not found.", cmd) os.Exit(1) } // some code here to check arguments perhaps? os.Exit(0) }