e41cf0e429
This commit adds a new testutil.CaptureStdio helper so that we
can test external go modules that use os.Std{out,err} but now
allow mocking or overwriting.
112 lines
2.1 KiB
Go
112 lines
2.1 KiB
Go
package testutil
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import (
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"bytes"
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"io"
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"os"
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"path/filepath"
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"strings"
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"sync"
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"testing"
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"github.com/stretchr/testify/require"
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)
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type MockCmd struct {
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binDir string
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name string
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}
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func MockCommand(t *testing.T, name string, script string) *MockCmd {
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mockCmd := &MockCmd{
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binDir: t.TempDir(),
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name: name,
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}
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fullScript := `#!/bin/bash -e
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for arg in "$@"; do
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echo -e -n "$arg\x0" >> "$0".run
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done
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echo >> "$0".run
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` + script
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t.Setenv("PATH", mockCmd.binDir+":"+os.Getenv("PATH"))
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err := os.WriteFile(filepath.Join(mockCmd.binDir, name), []byte(fullScript), 0755)
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require.NoError(t, err)
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return mockCmd
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}
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func (mc *MockCmd) Path() string {
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return filepath.Join(mc.binDir, mc.name)
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}
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func (mc *MockCmd) Restore() error {
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return os.RemoveAll(mc.binDir)
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}
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func (mc *MockCmd) Calls() [][]string {
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b, err := os.ReadFile(mc.Path() + ".run")
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if os.IsNotExist(err) {
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return nil
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}
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if err != nil {
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panic(err)
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}
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var calls [][]string
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for _, line := range strings.Split(string(b), "\n") {
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if line == "" {
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continue
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}
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call := strings.Split(line, "\000")
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calls = append(calls, call[0:len(call)-1])
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}
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return calls
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}
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// CaptureStdio runs the given function f() in an environment that
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// captures stdout, stderr and returns the the result as string.
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//
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// Use this very targeted to avoid real stdout/stderr output
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// from being displayed.
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func CaptureStdio(t *testing.T, f func()) (string, string) {
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saved1 := os.Stdout
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saved2 := os.Stderr
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r1, w1, err := os.Pipe()
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require.NoError(t, err)
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defer r1.Close()
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defer w1.Close()
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r2, w2, err := os.Pipe()
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require.NoError(t, err)
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defer r2.Close()
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defer w2.Close()
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var wg sync.WaitGroup
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var stdout, stderr bytes.Buffer
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wg.Add(1)
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// this needs to be a go-routines or we could deadlock
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// when the pipe is full
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go func() {
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defer wg.Done()
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io.Copy(&stdout, r1)
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}()
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wg.Add(1)
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go func() {
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defer wg.Done()
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io.Copy(&stderr, r2)
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}()
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os.Stdout = w1
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os.Stderr = w2
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defer func() {
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os.Stdout = saved1
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os.Stderr = saved2
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}()
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f()
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w1.Close()
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w2.Close()
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wg.Wait()
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return stdout.String(), stderr.String()
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}
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