fix: Inconsistent and flaky unit-tests

app_test.go

@@ -821,10 +821,15 @@ func Test_App_ShutdownWithTimeout(t *testing.T) {
 		time.Sleep(5 * time.Second)
 		return c.SendString("body")
 	})
+
 	ln := fasthttputil.NewInmemoryListener()
 	go func() {
-		require.NoError(t, app.Listener(ln))
+		err := app.Listener(ln)
+		if err != nil {
+			panic(err)
+		}
 	}()
+
 	time.Sleep(1 * time.Second)
 	go func() {
 		conn, err := ln.Dial()
@@ -866,7 +871,10 @@ func Test_App_ShutdownWithContext(t *testing.T) {
 	ln := fasthttputil.NewInmemoryListener()
 
 	go func() {
-		require.NoError(t, app.Listener(ln))
+		err := app.Listener(ln)
+		if err != nil {
+			panic(err)
+		}
 	}()
 
 	time.Sleep(1 * time.Second)

client.go

@@ -604,14 +604,24 @@ func (a *Agent) MultipartForm(args *Args) *Agent {
 		})
 	}
 
-	for _, ff := range a.formFiles {
-		w, err := a.mw.CreateFormFile(ff.Fieldname, ff.Name)
-		if err != nil {
-			a.errs = append(a.errs, err)
-			continue
-		}
-		if _, err = w.Write(ff.Content); err != nil {
-			a.errs = append(a.errs, err)
+	// Check if a.formFiles is not nil to avoid nil dereference
+	if a.formFiles != nil {
+		for _, ff := range a.formFiles {
+			// Additionally, check if ff is not nil to avoid nil dereference
+			if ff == nil {
+				continue // Skip this iteration if ff is nil
+			}
+			w, err := a.mw.CreateFormFile(ff.Fieldname, ff.Name)
+			if err != nil {
+				a.errs = append(a.errs, err)
+				continue
+			}
+			// Check if ff.Content is not nil before writing
+			if ff.Content != nil {
+				if _, err = w.Write(ff.Content); err != nil {
+					a.errs = append(a.errs, err)
+				}
+			}
 		}
 	}
 
@@ -854,10 +864,12 @@ func (a *Agent) reset() {
 	a.Name = ""
 	a.NoDefaultUserAgentHeader = false
 	for i, ff := range a.formFiles {
-		if ff.autoRelease {
-			ReleaseFormFile(ff)
+		if ff != nil {
+			if ff.autoRelease {
+				ReleaseFormFile(ff)
+			}
+			a.formFiles[i] = nil
 		}
-		a.formFiles[i] = nil
 	}
 	a.formFiles = a.formFiles[:0]
 }