mv captureStdout as public func

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

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)
+		}
+	}
+}