mv captureStdout as public func

Signed-off-by: yxxhero <aiopsclub@163.com>

pkg/testutil/testutil.go

@@ -0,0 +1,40 @@
+package testutil
+
+import (
+	"bytes"
+	"io"
+	"log"
+	"os"
+	"sync"
+)
+
+// CaptureStdout is a helper function to capture stdout.
+func CaptureStdout(f func()) string {
+	reader, writer, err := os.Pipe()
+	if err != nil {
+		panic(err)
+	}
+	stdout := os.Stdout
+	defer func() {
+		os.Stdout = stdout
+		log.SetOutput(os.Stderr)
+	}()
+	os.Stdout = writer
+	log.SetOutput(writer)
+	out := make(chan string)
+	wg := new(sync.WaitGroup)
+	wg.Add(1)
+	go func() {
+		var buf bytes.Buffer
+		wg.Done()
+		_, err = io.Copy(&buf, reader)
+		if err != nil {
+			panic(err)
+		}
+		out <- buf.String()
+	}()
+	wg.Wait()
+	f()
+	writer.Close()
+	return <-out
+}

pkg/testutil/testutil_test.go

@@ -0,0 +1,40 @@
+package testutil
+
+import (
+	"fmt"
+	"testing"
+)
+
+// TestCaptureStdout tests the CaptureStdout function.
+func TestCaptureStdout(t *testing.T) {
+	tests := []struct {
+		output   string
+		expected string
+	}{
+		{
+			output:   "123",
+			expected: "123",
+		},
+		{
+			output:   "test",
+			expected: "test",
+		},
+		{
+			output:   "",
+			expected: "",
+		},
+		{
+			output:   "...",
+			expected: "...",
+		},
+	}
+
+	for _, test := range tests {
+		result := CaptureStdout(func() {
+			fmt.Print(test.output)
+		})
+		if result != test.expected {
+			t.Errorf("CaptureStdout() = %v, want %v", result, test.expected)
+		}
+	}
+}