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// Copyright 2014 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// go command is not available on android
// +build !android
package main
import (
"bytes"
"fmt"
"go/build"
"io"
"io/ioutil"
"os"
"os/exec"
"path/filepath"
"strings"
"testing"
)
// This file contains a test that compiles and runs each program in testdata
// after generating the string method for its type. The rule is that for testdata/x.go
// we run stringer -type X and then compile and run the program. The resulting
// binary panics if the String method for X is not correct, including for error cases.
func TestEndToEnd(t *testing.T) {
dir, stringer := buildStringer(t)
defer os.RemoveAll(dir)
// Read the testdata directory.
fd, err := os.Open("testdata")
if err != nil {
t.Fatal(err)
}
defer fd.Close()
names, err := fd.Readdirnames(-1)
if err != nil {
t.Fatalf("Readdirnames: %s", err)
}
// Generate, compile, and run the test programs.
for _, name := range names {
if !strings.HasSuffix(name, ".go") {
t.Errorf("%s is not a Go file", name)
continue
}
if strings.HasPrefix(name, "tag_") {
// This file is used for tag processing in TestTags, below.
continue
}
if name == "cgo.go" && !build.Default.CgoEnabled {
t.Logf("cgo is not enabled for %s", name)
continue
}
// Names are known to be ASCII and long enough.
typeName := fmt.Sprintf("%c%s", name[0]+'A'-'a', name[1:len(name)-len(".go")])
stringerCompileAndRun(t, dir, stringer, typeName, name)
}
}
// TestTags verifies that the -tags flag works as advertised.
func TestTags(t *testing.T) {
dir, stringer := buildStringer(t)
defer os.RemoveAll(dir)
var (
protectedConst = []byte("TagProtected")
output = filepath.Join(dir, "const_string.go")
)
for _, file := range []string{"tag_main.go", "tag_tag.go"} {
err := copy(filepath.Join(dir, file), filepath.Join("testdata", file))
if err != nil {
t.Fatal(err)
}
}
err := run(stringer, "-type", "Const", dir)
if err != nil {
t.Fatal(err)
}
result, err := ioutil.ReadFile(output)
if err != nil {
t.Fatal(err)
}
if bytes.Contains(result, protectedConst) {
t.Fatal("tagged variable appears in untagged run")
}
err = os.Remove(output)
if err != nil {
t.Fatal(err)
}
err = run(stringer, "-type", "Const", "-tags", "tag", dir)
if err != nil {
t.Fatal(err)
}
result, err = ioutil.ReadFile(output)
if err != nil {
t.Fatal(err)
}
if !bytes.Contains(result, protectedConst) {
t.Fatal("tagged variable does not appear in tagged run")
}
}
// buildStringer creates a temporary directory and installs stringer there.
func buildStringer(t *testing.T) (dir string, stringer string) {
t.Helper()
dir, err := ioutil.TempDir("", "stringer")
if err != nil {
t.Fatal(err)
}
stringer = filepath.Join(dir, "stringer.exe")
err = run("go", "build", "-o", stringer)
if err != nil {
t.Fatalf("building stringer: %s", err)
}
return dir, stringer
}
// stringerCompileAndRun runs stringer for the named file and compiles and
// runs the target binary in directory dir. That binary will panic if the String method is incorrect.
func stringerCompileAndRun(t *testing.T, dir, stringer, typeName, fileName string) {
t.Helper()
t.Logf("run: %s %s\n", fileName, typeName)
source := filepath.Join(dir, fileName)
err := copy(source, filepath.Join("testdata", fileName))
if err != nil {
t.Fatalf("copying file to temporary directory: %s", err)
}
stringSource := filepath.Join(dir, typeName+"_string.go")
// Run stringer in temporary directory.
err = run(stringer, "-type", typeName, "-output", stringSource, source)
if err != nil {
t.Fatal(err)
}
// Run the binary in the temporary directory.
err = run("go", "run", stringSource, source)
if err != nil {
t.Fatal(err)
}
}
// copy copies the from file to the to file.
func copy(to, from string) error {
toFd, err := os.Create(to)
if err != nil {
return err
}
defer toFd.Close()
fromFd, err := os.Open(from)
if err != nil {
return err
}
defer fromFd.Close()
_, err = io.Copy(toFd, fromFd)
return err
}
// run runs a single command and returns an error if it does not succeed.
// os/exec should have this function, to be honest.
func run(name string, arg ...string) error {
cmd := exec.Command(name, arg...)
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
return cmd.Run()
}
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