check-safety/errleak_test.go

package main

import (
	"testing"
)

func TestCheckErrLeak_HttpErrorWithErrError(t *testing.T) {
	dir := t.TempDir()
	writeFile(t, dir, "handler.go", `package handler

import "net/http"

func handle(w http.ResponseWriter, r *http.Request) {
	err := doSomething()
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
	}
}
`)
	vs := checkErrLeak(dir)
	if len(vs) == 0 {
		t.Fatal("expected errleak violation for http.Error(w, err.Error(), ...)")
	}
	found := false
	for _, v := range vs {
		if v.file == "handler.go" {
			found = true
		}
	}
	if !found {
		t.Fatalf("expected violation in handler.go, got %#v", vs)
	}
}

func TestCheckErrLeak_FmtFprintfWithErrError(t *testing.T) {
	dir := t.TempDir()
	writeFile(t, dir, "handler.go", `package handler

import "fmt"

func handle(w interface{}, err error) {
	fmt.Fprintf(w, "error: %s", err.Error())
}
`)
	vs := checkErrLeak(dir)
	if len(vs) == 0 {
		t.Fatal("expected errleak violation for fmt.Fprintf(w, ..., err.Error())")
	}
}

func TestCheckErrLeak_FmtFprintlnWithErrError(t *testing.T) {
	dir := t.TempDir()
	writeFile(t, dir, "handler.go", `package handler

import "fmt"

func handle(w interface{}, err error) {
	fmt.Fprintln(w, err.Error())
}
`)
	vs := checkErrLeak(dir)
	if len(vs) == 0 {
		t.Fatal("expected errleak violation for fmt.Fprintln(w, err.Error())")
	}
}

func TestCheckErrLeak_WriteWithErrError(t *testing.T) {
	dir := t.TempDir()
	writeFile(t, dir, "handler.go", `package handler

func handle(w interface{ Write([]byte) (int, error) }, err error) {
	w.Write([]byte(err.Error()))
}
`)
	vs := checkErrLeak(dir)
	if len(vs) == 0 {
		t.Fatal("expected errleak violation for w.Write([]byte(err.Error()))")
	}
}

func TestCheckErrLeak_SafeErrorHelpers_Clean(t *testing.T) {
	// Using writeInternalServerError helper — should NOT flag
	dir := t.TempDir()
	writeFile(t, dir, "handler.go", `package handler

func handle(w http.ResponseWriter, r *http.Request) {
	err := doSomething()
	if err != nil {
		writeInternalServerError(w, err, "handle request")
	}
}
`)
	vs := checkErrLeak(dir)
	if len(vs) != 0 {
		t.Fatalf("expected no violations for safe helper usage, got %d: %#v", len(vs), vs)
	}
}

func TestCheckErrLeak_HttpErrorWithLiteralMessage_Clean(t *testing.T) {
	// http.Error with a literal string — NOT a leak
	dir := t.TempDir()
	writeFile(t, dir, "handler.go", `package handler

import "net/http"

func handle(w http.ResponseWriter, r *http.Request) {
	http.Error(w, "internal server error", http.StatusInternalServerError)
}
`)
	vs := checkErrLeak(dir)
	if len(vs) != 0 {
		t.Fatalf("expected no violations for http.Error with literal message, got %d: %#v", len(vs), vs)
	}
}

func TestCheckErrLeak_TestFile_Skipped(t *testing.T) {
	dir := t.TempDir()
	writeFile(t, dir, "handler_test.go", `package handler

import "net/http"

func TestHandle(t *testing.T) {
	http.Error(w, err.Error(), 500)
}
`)
	vs := checkErrLeak(dir)
	if len(vs) != 0 {
		t.Fatalf("expected test files to be skipped, got %d violations", len(vs))
	}
}

func TestCheckErrLeak_RelativeFilePath(t *testing.T) {
	dir := t.TempDir()
	writeFile(t, dir, "leak.go", `package handler

import "net/http"

func f(w http.ResponseWriter, err error) {
	http.Error(w, err.Error(), 500)
}
`)
	vs := checkErrLeak(dir)
	if len(vs) == 0 {
		t.Fatal("expected violation")
	}
	if vs[0].file != "leak.go" {
		t.Fatalf("expected relative file 'leak.go', got %q", vs[0].file)
	}
}

func TestCheckErrLeak_NonGoFile_Skipped(t *testing.T) {
	dir := t.TempDir()
	// Write something that looks like an errleak pattern but in a .ts file
	writeFile(t, dir, "handler.ts", `// err.Error() leaks
http.Error(w, err.Error(), 500)
`)
	vs := checkErrLeak(dir)
	if len(vs) != 0 {
		t.Fatalf("expected no violations for non-.go file, got %d", len(vs))
	}
}

func TestCheckErrLeak_SnippetContainsPattern(t *testing.T) {
	dir := t.TempDir()
	writeFile(t, dir, "handler.go", `package handler

import "net/http"

func handle(w http.ResponseWriter, err error) {
	http.Error(w, err.Error(), http.StatusBadRequest)
}
`)
	vs := checkErrLeak(dir)
	if len(vs) == 0 {
		t.Fatal("expected violation")
	}
	// snippet should mention the pattern name
	if vs[0].snippet == "" {
		t.Fatal("expected non-empty snippet")
	}
}