tools/lib/subprocess/subprocess_test.go

// Copyright 2019 The Fuchsia Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

package subprocess

import (
	"bytes"
	"context"
	"errors"
	"os/exec"
	"strings"
	"testing"
)

func TestRun(t *testing.T) {
	t.Run("Run", func(t *testing.T) {
		t.Run("should execute a command", func(t *testing.T) {
			r := Runner{
				Env: []string{"FOO=bar"}, // Cover env var handling.
			}
			message := "Hello, World!"
			command := []string{"echo", message}

			stdout := new(bytes.Buffer)
			stderr := new(bytes.Buffer)
			if err := r.Run(context.Background(), command, stdout, stderr); err != nil {
				t.Fatal(err)
			}

			stdoutS := strings.TrimSpace(stdout.String())
			if stdoutS != message {
				t.Fatalf("Expected output %q, but got %q", message, stdoutS)
			}

			stderrS := strings.TrimSpace(stderr.String())
			if stderrS != "" {
				t.Fatalf("Expected empty stderr, but got %q", stderrS)
			}
		})

		t.Run("should error if the context completes before the command", func(t *testing.T) {
			ctx, cancel := context.WithCancel(context.Background())
			cancel()

			r := Runner{}
			command := []string{"sleep", "5"}
			err := r.Run(ctx, command, nil, nil)
			if err == nil {
				t.Fatal("Expected sleep command to terminate early but it completed")
			} else if !errors.Is(err, ctx.Err()) {
				t.Fatalf("Expected Run() to return a context error after cancelation but got: %s", err)
			}
		})

		t.Run("should return an error if the command fails", func(t *testing.T) {
			r := Runner{}
			command := []string{"not_a_command_12345"}
			err := r.Run(context.Background(), command, nil, nil)
			if err == nil {
				t.Fatalf("Expected invalid command to fail but it succeeded: %s", err)
			} else if !errors.Is(err, exec.ErrNotFound) {
				t.Fatalf("Expected Run() to return exec.ErrNotFound but got: %s", err)
			}
		})
	})
}