Testing Exit, Fatal, and Panic in Golang 2/3

Test_exit_fatal_panic_2.go

package main

import (
	"bytes"
	"log"
	"os"
	"testing"
)

func TestLogFatal(t *testing.T) {
	// Save original os.Exit
	originalExit := os.Exit
	defer func() { os.Exit = originalExit }()

	exitCalled := false

	// Mock os.Exit
	os.Exit = func(code int) {
		exitCalled = true
		panic("os.Exit called")
	}

	// Capture stderr
	var buf bytes.Buffer
	log.SetOutput(&buf)
	defer log.SetOutput(os.Stderr)

	// Test the function
	func() {
		defer func() { recover() }()
		log.Fatal("Fatal error occurred")
	}()

	// Verify output
	if !exitCalled {
		t.Errorf("os.Exit was not called")
	}
	if !bytes.Contains(buf.Bytes(), []byte("Fatal error occurred")) {
		t.Errorf("Expected log message not found: %s", buf.String())
	}
}