cmd/cmdtest/test_cmd.go
// Copyright 2017 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package cmdtest
import (
"bufio"
"bytes"
"fmt"
"io"
"io/ioutil"
"os"
"os/exec"
"regexp"
"strings"
"sync"
"syscall"
"testing"
"text/template"
"github.com/docker/docker/pkg/reexec"
)
func NewTestCmd(t *testing.T, data interface{}) *TestCmd {
return &TestCmd{T: t, Data: data}
}
type TestCmd struct {
// For total convenience, all testing methods are available.
*testing.T
Func template.FuncMap
Data interface{}
Cleanup func()
cmd *exec.Cmd
stdout *bufio.Reader
stdin io.WriteCloser
stderr *testlogger
// Err will contain the process exit error or interrupt signal error
Err error
}
// Run exec's the current binary using name as argv[0] which will trigger the
// reexec init function for that name (e.g. "lachesis-test" in cmd/run_test.go)
func (tt *TestCmd) Run(name string, args ...string) {
tt.stderr = &testlogger{t: tt.T}
tt.cmd = &exec.Cmd{
Path: reexec.Self(),
Args: append([]string{name}, args...),
Stderr: tt.stderr,
}
stdout, err := tt.cmd.StdoutPipe()
if err != nil {
tt.Fatal(err)
}
tt.stdout = bufio.NewReader(stdout)
if tt.stdin, err = tt.cmd.StdinPipe(); err != nil {
tt.Fatal(err)
}
if err := tt.cmd.Start(); err != nil {
tt.Fatal(err)
}
}
// InputLine writes the given text to the childs stdin.
// This method can also be called from an expect template, e.g.:
//
// cli.expect(`Passphrase: {{.InputLine "password"}}`)
func (tt *TestCmd) InputLine(s string) string {
io.WriteString(tt.stdin, s+"\n")
return ""
}
func (tt *TestCmd) SetTemplateFunc(name string, fn interface{}) {
if tt.Func == nil {
tt.Func = make(map[string]interface{})
}
tt.Func[name] = fn
}
// Expect runs its argument as a template, then expects the
// child process to output the result of the template within 5s.
//
// If the template starts with a newline, the newline is removed
// before matching.
func (tt *TestCmd) Expect(tplsource string) {
// Generate the expected output by running the template.
tpl := template.Must(template.New("").Funcs(tt.Func).Parse(tplsource))
wantbuf := new(bytes.Buffer)
if err := tpl.Execute(wantbuf, tt.Data); err != nil {
panic(err)
}
// Trim exactly one newline at the beginning. This makes tests look
// much nicer because all expect strings are at column 0.
want := bytes.TrimPrefix(wantbuf.Bytes(), []byte("\n"))
if err := tt.matchExactOutput(want); err != nil {
tt.Fatal(err)
}
tt.Logf("Matched stdout text:\n%s", want)
}
func (tt *TestCmd) matchExactOutput(want []byte) error {
buf := make([]byte, len(want))
n := 0
n, _ = io.ReadFull(tt.stdout, buf)
buf = buf[:n]
if n < len(want) || !bytes.Equal(buf, want) {
// Grab any additional buffered output in case of mismatch
// because it might help with debugging.
buf = append(buf, make([]byte, tt.stdout.Buffered())...)
tt.stdout.Read(buf[n:])
// Find the mismatch position.
for i := 0; i < n; i++ {
if want[i] != buf[i] {
return fmt.Errorf("Output mismatch at ā:\n---------------- (stdout text)\n%sā%s\n---------------- (expected text)\n%s",
buf[:i], buf[i:n], want)
}
}
if n < len(want) {
return fmt.Errorf("Not enough output, got until ā:\n---------------- (stdout text)\n%s\n---------------- (expected text)\n%sā%s",
buf, want[:n], want[n:])
}
}
return nil
}
// ExpectRegexp expects the child process to output text matching the
// given regular expression within 5s.
//
// Note that an arbitrary amount of output may be consumed by the
// regular expression. This usually means that expect cannot be used
// after ExpectRegexp.
func (tt *TestCmd) ExpectRegexp(regex string) (*regexp.Regexp, []string) {
regex = strings.TrimPrefix(regex, "\n")
var (
re = regexp.MustCompile(regex)
rtee = &runeTee{in: tt.stdout}
matches []int
)
matches = re.FindReaderSubmatchIndex(rtee)
output := rtee.buf.Bytes()
if matches == nil {
tt.Fatalf("Output did not match:\n---------------- (stdout text)\n%s\n---------------- (regular expression)\n%s",
output, regex)
return re, nil
}
tt.Logf("Matched stdout text:\n%s", output)
var submatches []string
for i := 0; i < len(matches); i += 2 {
submatch := string(output[matches[i]:matches[i+1]])
submatches = append(submatches, submatch)
}
return re, submatches
}
// ExpectExit expects the child process to exit within 5s without
// printing any additional text on stdout.
func (tt *TestCmd) ExpectExit() {
var output []byte
output, _ = ioutil.ReadAll(tt.stdout)
tt.WaitExit()
if tt.Cleanup != nil {
tt.Cleanup()
}
if len(output) > 0 {
tt.Errorf("Unmatched stdout text:\n%s", output)
}
}
func (tt *TestCmd) WaitExit() {
tt.Err = tt.cmd.Wait()
}
func (tt *TestCmd) Interrupt() {
tt.Err = tt.cmd.Process.Signal(os.Interrupt)
}
// ExitStatus exposes the process' OS exit code
// It will only return a valid value after the process has finished.
func (tt *TestCmd) ExitStatus() int {
if tt.Err != nil {
exitErr := tt.Err.(*exec.ExitError)
if exitErr != nil {
if status, ok := exitErr.Sys().(syscall.WaitStatus); ok {
return status.ExitStatus()
}
}
}
return 0
}
// StderrText returns any stderr output written so far.
// The returned text holds all log lines after ExpectExit has
// returned.
func (tt *TestCmd) StderrText() string {
tt.stderr.mu.Lock()
defer tt.stderr.mu.Unlock()
return tt.stderr.buf.String()
}
func (tt *TestCmd) CloseStdin() {
tt.stdin.Close()
}
func (tt *TestCmd) Kill() {
tt.cmd.Process.Kill()
if tt.Cleanup != nil {
tt.Cleanup()
}
}
// testlogger logs all written lines via t.Log and also
// collects them for later inspection.
type testlogger struct {
t *testing.T
mu sync.Mutex
buf bytes.Buffer
}
func (tl *testlogger) Write(b []byte) (n int, err error) {
lines := bytes.Split(b, []byte("\n"))
for _, line := range lines {
if len(line) > 0 {
tl.t.Logf("(stderr) %s", line)
}
}
tl.mu.Lock()
tl.buf.Write(b)
tl.mu.Unlock()
return len(b), err
}
// runeTee collects text read through it into buf.
type runeTee struct {
in interface {
io.Reader
io.ByteReader
io.RuneReader
}
buf bytes.Buffer
}
func (rtee *runeTee) Read(b []byte) (n int, err error) {
n, err = rtee.in.Read(b)
rtee.buf.Write(b[:n])
return n, err
}
func (rtee *runeTee) ReadRune() (r rune, size int, err error) {
r, size, err = rtee.in.ReadRune()
if err == nil {
rtee.buf.WriteRune(r)
}
return r, size, err
}
func (rtee *runeTee) ReadByte() (b byte, err error) {
b, err = rtee.in.ReadByte()
if err == nil {
rtee.buf.WriteByte(b)
}
return b, err
}