Add a library for running external commands, providing timeouts and test injection.

go/exec/exec_test.go

Index: go/exec/exec_test.go
diff --git a/go/exec/exec_test.go b/go/exec/exec_test.go
new file mode 100644
index 0000000000000000000000000000000000000000..74b020978ab2c1ce29521991107616b6753397aa
--- /dev/null
+++ b/go/exec/exec_test.go
@@ -0,0 +1,289 @@
+package exec
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/skia-dev/glog"
+	expect "github.com/stretchr/testify/assert"
+	assert "github.com/stretchr/testify/require"
+)
+
+// Copied from go.skia.org/infra/go/util/util.go to avoid recursive dependency.
+func RemoveAll(path string) {
+	if err := os.RemoveAll(path); err != nil {
+		glog.Errorf("Failed to RemoveAll(%s): %v", path, err)
+	}
+}
+
+func TestParseCommand(t *testing.T) {
+	test := func(input string, expected Command) {
+		expect.Equal(t, expected, ParseCommand(input))
+	}
+	test("", Command{Name: "", Args: []string{}})
+	test("foo", Command{Name: "foo", Args: []string{}})
+	test("foo bar", Command{Name: "foo", Args: []string{"bar"}})
+	test("foo_bar baz", Command{Name: "foo_bar", Args: []string{"baz"}})
+	test("foo-bar baz", Command{Name: "foo-bar", Args: []string{"baz"}})
+	test("foo --bar --baz", Command{Name: "foo", Args: []string{"--bar", "--baz"}})
+	// Doesn't work.
+	//test("foo 'bar baz'", Command{Name: "foo", Args: []string{"bar baz"}})
+}
+
+func TestSquashWriters(t *testing.T) {
+	test := func(input ...*bytes.Buffer) {
+		writers := make([]io.Writer, len(input))
+		for i, buffer := range input {
+			if buffer != nil {
+				writers[i] = buffer
+			}
+		}
+		squashed := squashWriters(writers...)
+		assert.NotNil(t, squashed)
+		testString1, testString2 := "foobar", "baz"
+		n, err := squashed.Write([]byte(testString1))
+		expect.Equal(t, len(testString1), n)
+		expect.NoError(t, err)
+		n, err = squashed.Write([]byte(testString2))
+		expect.Equal(t, len(testString2), n)
+		expect.NoError(t, err)
+		for _, buffer := range input {
+			if buffer != nil {
+				expect.Equal(t, testString1+testString2, string(buffer.Bytes()))
+			}
+		}
+	}
+	expect.Equal(t, nil, squashWriters())
+	expect.Equal(t, nil, squashWriters(nil))
+	expect.Equal(t, nil, squashWriters(nil, nil))
+	test(&bytes.Buffer{})
+	test(&bytes.Buffer{}, &bytes.Buffer{})
+	test(&bytes.Buffer{}, nil)
+	test(nil, &bytes.Buffer{})
+	test(&bytes.Buffer{}, &bytes.Buffer{}, &bytes.Buffer{})
+	test(&bytes.Buffer{}, nil, nil)
+	test(nil, &bytes.Buffer{}, nil)
+	test(nil, nil, &bytes.Buffer{})
+	test(&bytes.Buffer{}, nil, &bytes.Buffer{})
+}
+
+func TestBasic(t *testing.T) {
+	dir, err := ioutil.TempDir("", "exec_test")
+	assert.NoError(t, err)
+	defer RemoveAll(dir)
+	file := filepath.Join(dir, "ran")
+	assert.NoError(t, Run(&Command{
+		Name: "touch",
+		Args: []string{file},
+	}))
+	_, err = os.Stat(file)
+	expect.NoError(t, err)
+}
+
+func WriteScript(path, script string) error {
+	return ioutil.WriteFile(path, []byte(script), 0777)
+}
+
+const SimpleScript = `#!/bin/bash
+touch "${EXEC_TEST_FILE}"
+`
+
+func TestEnv(t *testing.T) {
+	dir, err := ioutil.TempDir("", "exec_test")
+	assert.NoError(t, err)
+	defer RemoveAll(dir)
+	script := filepath.Join(dir, "simple_script.sh")
+	assert.NoError(t, WriteScript(script, SimpleScript))
+	file := filepath.Join(dir, "ran")
+	assert.NoError(t, Run(&Command{
+		Name: script,
+		Env:  []string{fmt.Sprintf("EXEC_TEST_FILE=%s", file)},
+	}))
+	_, err = os.Stat(file)
+	expect.NoError(t, err)
+}
+
+const PathScript = `#!/bin/bash
+echo "${PATH}" > "${EXEC_TEST_FILE}"
+`
+
+func TestInheritPath(t *testing.T) {
+	dir, err := ioutil.TempDir("", "exec_test")
+	assert.NoError(t, err)
+	defer RemoveAll(dir)
+	script := filepath.Join(dir, "path_script.sh")
+	assert.NoError(t, WriteScript(script, PathScript))
+	file := filepath.Join(dir, "ran")
+	assert.NoError(t, Run(&Command{
+		Name:        script,
+		Env:         []string{fmt.Sprintf("EXEC_TEST_FILE=%s", file)},
+		InheritPath: true,
+	}))
+	contents, err := ioutil.ReadFile(file)
+	assert.NoError(t, err)
+	expect.Equal(t, os.Getenv("PATH"), strings.TrimSpace(string(contents)))
+}
+
+const HelloScript = `#!/bin/bash
+echo "Hello World!" > output.txt
+`
+
+func TestDir(t *testing.T) {
+	dir1, err := ioutil.TempDir("", "exec_test1")
+	assert.NoError(t, err)
+	defer RemoveAll(dir1)
+	script := filepath.Join(dir1, "hello_script.sh")
+	assert.NoError(t, WriteScript(script, HelloScript))
+	dir2, err := ioutil.TempDir("", "exec_test2")
+	assert.NoError(t, err)
+	defer RemoveAll(dir2)
+	assert.NoError(t, Run(&Command{
+		Name: script,
+		Dir:  dir2,
+	}))
+	file := filepath.Join(dir2, "output.txt")
+	_, err = os.Stat(file)
+	expect.NoError(t, err)
+}
+
+func TestSimpleIO(t *testing.T) {
+	inputString := "foo\nbar\nbaz\n"
+	output := bytes.Buffer{}
+	assert.NoError(t, Run(&Command{
+		Name:   "grep",
+		Args:   []string{"-e", "^ba"},
+		Stdin:  bytes.NewReader([]byte(inputString)),
+		Stdout: &output,
+	}))
+	expect.Equal(t, "bar\nbaz\n", string(output.Bytes()))
+}
+
+func TestError(t *testing.T) {
+	dir, err := ioutil.TempDir("", "exec_test")
+	assert.NoError(t, err)
+	defer RemoveAll(dir)
+	output := bytes.Buffer{}
+	err = Run(&Command{
+		Name: "cp",
+		Args: []string{filepath.Join(dir, "doesnt_exist"),
+			filepath.Join(dir, "dest")},
+		Stderr: &output,
+	})
+	expect.Error(t, err)
+	expect.Contains(t, err.Error(), "exit status 1")
+	expect.Contains(t, string(output.Bytes()), "No such file or directory")
+}
+
+const CombinedOutputScript = `#!/bin/bash
+echo "roses"
+>&2 echo "red"
+echo "violets"
+>&2 echo "blue"
+`
+
+func TestCombinedOutput(t *testing.T) {
+	dir, err := ioutil.TempDir("", "exec_test")
+	assert.NoError(t, err)
+	defer RemoveAll(dir)
+	script := filepath.Join(dir, "combined_output_script.sh")
+	assert.NoError(t, WriteScript(script, CombinedOutputScript))
+	combined := bytes.Buffer{}
+	assert.NoError(t, Run(&Command{
+		Name:           script,
+		CombinedOutput: &combined,
+	}))
+	expect.Equal(t, "roses\nred\nviolets\nblue\n", string(combined.Bytes()))
+}
+
+// Previously there was a bug due to code like:
+// var outputFile *os.File
+// if outputToFile {
+// 	outputFile = ...
+// }
+// Run(&Command{... Stdout: outputFile})
+// See http://devs.cloudimmunity.com/gotchas-and-common-mistakes-in-go-golang/index.html#nil_in_nil_in_vals
+func TestNilIO(t *testing.T) {
+	inputString := "foo\nbar\nbaz\n"
+	assert.NoError(t, Run(&Command{
+		Name:   "grep",
+		Args:   []string{"-e", "^ba"},
+		Stdin:  bytes.NewReader([]byte(inputString)),
+		Stdout: (*os.File)(nil),
+	}))
+}
+
+const SleeperScript = `#!/bin/bash
+sleep 3
+touch ran
+`
+
+func TestTimeoutNotReached(t *testing.T) {
+	dir, err := ioutil.TempDir("", "exec_test")
+	assert.NoError(t, err)
+	defer RemoveAll(dir)
+	script := filepath.Join(dir, "sleeper_script.sh")
+	assert.NoError(t, WriteScript(script, SleeperScript))
+	assert.NoError(t, Run(&Command{
+		Name:    script,
+		Dir:     dir,
+		Timeout: time.Minute,
+	}))
+	file := filepath.Join(dir, "ran")
+	_, err = os.Stat(file)
+	expect.NoError(t, err)
+}
+
+func TestTimeoutExceeded(t *testing.T) {
+	dir, err := ioutil.TempDir("", "exec_test")
+	assert.NoError(t, err)
+	defer RemoveAll(dir)
+	script := filepath.Join(dir, "sleeper_script.sh")
+	assert.NoError(t, WriteScript(script, SleeperScript))
+	err = Run(&Command{
+		Name:    script,
+		Dir:     dir,
+		Timeout: time.Second,
+	})
+	expect.Error(t, err)
+	expect.Contains(t, err.Error(), "Command killed")
+	file := filepath.Join(dir, "ran")
+	_, err = os.Stat(file)
+	expect.True(t, os.IsNotExist(err))
+}
+
+func TestInjection(t *testing.T) {
+	var actualCommand *Command
+	SetRunForTesting(func(command *Command) error {
+		actualCommand = command
+		return nil
+	})
+	defer SetRunForTesting(DefaultRun)
+
+	dir, err := ioutil.TempDir("", "exec_test")
+	assert.NoError(t, err)
+	defer RemoveAll(dir)
+	file := filepath.Join(dir, "ran")
+	assert.NoError(t, Run(&Command{
+		Name: "touch",
+		Args: []string{file},
+	}))
+	_, err = os.Stat(file)
+	expect.True(t, os.IsNotExist(err))
+
+	expect.Equal(t, "touch", actualCommand.Name)
+	expect.Equal(t, 1, len(actualCommand.Args))
+	expect.Equal(t, file, actualCommand.Args[0])
+}
+
+func TestRunSimple(t *testing.T) {
+	output, err := RunSimple(`echo "Hello Go!"`)
+	assert.NoError(t, err)
+	expect.Equal(t, "\"Hello Go!\"\n", output)
+}