🩹 Fix: Fix app.Test() auto-failing when a connection is closed early (#3279)

* ♻️ Refactor: Extract testConn err to variable

* ♻️ Refactor: Extract ErrTestGotEmptyResponse from app.Test()

* 🩹 Fix: Fix `app.Test()` auto-failing when testConn is closed

* 🩹 Fix(app_test.go): Use tab for indent instead of spaces

* 🩹 Fix(app_test.go): Fix to respect gofmt linter

* ♻️ Refactor: Update Drop tests to verify error type

app.go

@@ -941,6 +941,8 @@ func (app *App) Hooks() *Hooks {
 	return app.hooks
 }
 
+var ErrTestGotEmptyResponse = errors.New("test: got empty response")
+
 // TestConfig is a struct holding Test settings
 type TestConfig struct {
 	// Timeout defines the maximum duration a
@@ -1022,7 +1024,7 @@ func (app *App) Test(req *http.Request, config ...TestConfig) (*http.Response, e
 	}
 
 	// Check for errors
-	if err != nil && !errors.Is(err, fasthttp.ErrGetOnly) {
+	if err != nil && !errors.Is(err, fasthttp.ErrGetOnly) && !errors.Is(err, errTestConnClosed) {
 		return nil, err
 	}
 
@@ -1033,7 +1035,7 @@ func (app *App) Test(req *http.Request, config ...TestConfig) (*http.Response, e
 	res, err := http.ReadResponse(buffer, req)
 	if err != nil {
 		if errors.Is(err, io.ErrUnexpectedEOF) {
-			return nil, errors.New("test: got empty response")
+			return nil, ErrTestGotEmptyResponse
 		}
 		return nil, fmt.Errorf("failed to read response: %w", err)
 	}

app_test.go

@@ -1491,7 +1491,7 @@ func Test_App_Test_timeout(t *testing.T) {
 		Timeout:       100 * time.Millisecond,
 		FailOnTimeout: true,
 	})
-	require.Equal(t, os.ErrDeadlineExceeded, err)
+	require.ErrorIs(t, err, os.ErrDeadlineExceeded)
 }
 
 func Test_App_Test_timeout_empty_response(t *testing.T) {
@@ -1507,7 +1507,22 @@ func Test_App_Test_timeout_empty_response(t *testing.T) {
 		Timeout:       100 * time.Millisecond,
 		FailOnTimeout: false,
 	})
-	require.Equal(t, errors.New("test: got empty response"), err)
+	require.ErrorIs(t, err, ErrTestGotEmptyResponse)
+}
+
+func Test_App_Test_drop_empty_response(t *testing.T) {
+	t.Parallel()
+
+	app := New()
+	app.Get("/", func(c Ctx) error {
+		return c.Drop()
+	})
+
+	_, err := app.Test(httptest.NewRequest(MethodGet, "/", nil), TestConfig{
+		Timeout:       0,
+		FailOnTimeout: false,
+	})
+	require.ErrorIs(t, err, ErrTestGotEmptyResponse)
 }
 
 func Test_App_SetTLSHandler(t *testing.T) {

ctx_test.go

@@ -5896,7 +5896,7 @@ func Test_Ctx_Drop(t *testing.T) {
 
 	// Test the Drop method
 	resp, err := app.Test(httptest.NewRequest(MethodGet, "/block-me", nil))
-	require.Error(t, err)
+	require.ErrorIs(t, err, ErrTestGotEmptyResponse)
 	require.Nil(t, resp)
 
 	// Test the no-response handler
@@ -5927,7 +5927,7 @@ func Test_Ctx_DropWithMiddleware(t *testing.T) {
 
 	// Test the Drop method
 	resp, err := app.Test(httptest.NewRequest(MethodGet, "/block-me", nil))
-	require.Error(t, err)
+	require.ErrorIs(t, err, ErrTestGotEmptyResponse)
 	require.Nil(t, resp)
 }
 

helpers.go

@@ -612,6 +612,8 @@ func isNoCache(cacheControl string) bool {
 	return true
 }
 
+var errTestConnClosed = errors.New("testConn is closed")
+
 type testConn struct {
 	r        bytes.Buffer
 	w        bytes.Buffer
@@ -631,7 +633,7 @@ func (c *testConn) Write(b []byte) (int, error) {
 	defer c.Unlock()
 
 	if c.isClosed {
-		return 0, errors.New("testConn is closed")
+		return 0, errTestConnClosed
 	}
 	return c.w.Write(b) //nolint:wrapcheck // This must not be wrapped
 }

helpers_test.go

@@ -548,7 +548,7 @@ func Test_Utils_TestConn_Closed_Write(t *testing.T) {
 	// Close early, write should fail
 	conn.Close() //nolint:errcheck, revive // It is fine to ignore the error here
 	_, err = conn.Write([]byte("Response 2\n"))
-	require.Error(t, err)
+	require.ErrorIs(t, err, errTestConnClosed)
 
 	res := make([]byte, 11)
 	_, err = conn.w.Read(res)