first pass at generalizing process stubbing

git/git_test.go

@@ -2,62 +2,29 @@ package git
 
 import (
 	"fmt"
+	"github.com/github/gh-cli/test"
 	"os"
-	"os/exec"
 	"testing"
 )
 
-type outputSpec struct {
-	Stdout   string
-	ExitCode int
-}
-
-var _outputs map[string]outputSpec
-
-func init() {
-	_outputs = map[string]outputSpec{
-		"no changes": outputSpec{"", 0},
-		"one change": outputSpec{` M poem.txt
-`, 0},
-		"untracked file": outputSpec{` M poem.txt
-?? new.txt
-`, 0},
-		"boom": outputSpec{"", 1},
-	}
-}
-
-func TestHelperProcess(*testing.T) {
-	if os.Getenv("GO_WANT_HELPER_PROCESS") != "1" {
+func TestGitStatusHelperProcess(*testing.T) {
+	if test.SkipTestHelperProcess() {
 		return
 	}
-	args := os.Args
-	for len(args) > 0 {
-		if args[0] == "--" {
-			args = args[1:]
-			break
-		}
-		args = args[1:]
+	outputs := map[string]test.ExecStub{
+		"no changes": test.ExecStub{"", 0},
+		"one change": test.ExecStub{` M poem.txt
+`, 0},
+		"untracked file": test.ExecStub{` M poem.txt
+?? new.txt
+`, 0},
+		"boom": test.ExecStub{"", 1},
 	}
-	output := _outputs[args[0]]
+	output := test.GetExecStub(outputs)
 	defer os.Exit(output.ExitCode)
 	fmt.Println(output.Stdout)
 }
 
-func StubGit(desiredOutput string) func(...string) *exec.Cmd {
-	return func(args ...string) *exec.Cmd {
-		cs := []string{"-test.run=TestHelperProcess", "--", desiredOutput}
-		cs = append(cs, args...)
-		env := []string{
-			"GO_WANT_HELPER_PROCESS=1",
-		}
-
-		cmd := exec.Command(os.Args[0], cs...)
-		cmd.Env = append(env, os.Environ()...)
-		return cmd
-	}
-
-}
-
 func Test_UncommittedChangeCount(t *testing.T) {
 	origGitCommand := GitCommand
 	defer func() {
@@ -71,7 +38,7 @@ func Test_UncommittedChangeCount(t *testing.T) {
 	}
 
 	for k, v := range cases {
-		GitCommand = StubGit(k)
+		GitCommand = test.StubExecCommand("TestGitStatusHelperProcess", k)
 		ucc, _ := UncommittedChangeCount()
 
 		if ucc != v {
@@ -79,7 +46,7 @@ func Test_UncommittedChangeCount(t *testing.T) {
 		}
 	}
 
-	GitCommand = StubGit("boom")
+	GitCommand = test.StubExecCommand("TestGitStatusHelperProcess", "boom")
 	_, err := UncommittedChangeCount()
 	if err.Error() != "failed to run git status: exit status 1" {
 		t.Errorf("got unexpected error message: %s", err)

test/helpers.go

@@ -11,6 +11,43 @@ import (
 	"github.com/spf13/cobra"
 )
 
+type ExecStub struct {
+	Stdout   string
+	ExitCode int
+}
+
+func GetExecStub(outputs map[string]ExecStub) ExecStub {
+	args := os.Args
+	for len(args) > 0 {
+		if args[0] == "--" {
+			args = args[1:]
+			break
+		}
+		args = args[1:]
+	}
+	return outputs[args[0]]
+}
+
+func SkipTestHelperProcess() bool {
+	return os.Getenv("GO_WANT_HELPER_PROCESS") != "1"
+}
+
+func StubExecCommand(testHelper string, desiredOutput string) func(...string) *exec.Cmd {
+	return func(args ...string) *exec.Cmd {
+		cs := []string{
+			fmt.Sprintf("-test.run=%s", testHelper),
+			"--", desiredOutput}
+		cs = append(cs, args...)
+		env := []string{
+			"GO_WANT_HELPER_PROCESS=1",
+		}
+
+		cmd := exec.Command(os.Args[0], cs...)
+		cmd.Env = append(env, os.Environ()...)
+		return cmd
+	}
+}
+
 type TempGitRepo struct {
 	Remote   string
 	TearDown func()