Add a loader test.

api/internal/git/gitrunner.go

@@ -0,0 +1,65 @@
+// Copyright 2020 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package git
+
+import (
+	"os/exec"
+	"time"
+
+	"github.com/pkg/errors"
+	"sigs.k8s.io/kustomize/api/filesys"
+	"sigs.k8s.io/kustomize/api/types"
+)
+
+// Arbitrary, but non-infinite, timeout for running commands.
+const defaultDuration = 27 * time.Second
+
+// gitRunner runs the external git binary.
+type gitRunner struct {
+	gitProgram string
+	duration   time.Duration
+	dir        filesys.ConfirmedDir
+}
+
+// newCmdRunner returns a gitRunner if it can find the binary.
+// It also creats a temp directory for cloning repos.
+func newCmdRunner() (*gitRunner, error) {
+	gitProgram, err := exec.LookPath("git")
+	if err != nil {
+		return nil, errors.Wrap(err, "no 'git' program on path")
+	}
+	dir, err := filesys.NewTmpConfirmedDir()
+	if err != nil {
+		return nil, err
+	}
+	return &gitRunner{
+		gitProgram: gitProgram,
+		duration:   defaultDuration,
+		dir:        dir,
+	}, nil
+}
+
+// run a command with a timeout.
+func (r gitRunner) run(args ...string) (err error) {
+	ch := make(chan bool, 1)
+	defer close(ch)
+	//nolint: gosec
+	cmd := exec.Command(r.gitProgram, args...)
+	cmd.Dir = r.dir.String()
+	timer := time.NewTimer(r.duration)
+	defer timer.Stop()
+	go func() {
+		_, err = cmd.CombinedOutput()
+		ch <- true
+	}()
+	select {
+	case <-ch:
+		if err != nil {
+			return errors.Wrapf(err, "git cmd = '%s'", cmd.String())
+		}
+		return nil
+	case <-timer.C:
+		return types.NewErrTimeOut(r.duration, cmd.String())
+	}
+}