test(limiter): fix intermittent failures (gofiber#2716)

The limiter middleware unit tests are failing due to a race between the
storage garbage collector and the unit test itself. The sliding window
limiter tracks requests using memory storage. In several of the unit
tests, this storage expiry ends up being 4 seconds. The test waits for 4
seconds, then sends a request, expecting it to succeed. However, the
unit test occasionally wakes up before the storage GC kicks in. As an
effect of the very coarse timer (using seconds as units), the middleware
correctly rejects the request, causing the test to fail.

Update the sleep to 4.5 seconds. This will not slow down the execution
of the test suite, as these tests run in parallel with a separate 9
second long test.

I'm not 100% sure this solves the issue, and ideally we'd be able to
run tests without time.Sleep.

middleware/limiter/limiter_test.go

@@ -218,7 +218,7 @@ func Test_Limiter_Sliding_Window_No_Skip_Choices(t *testing.T) {
 	utils.AssertEqual(t, nil, err)
 	utils.AssertEqual(t, 429, resp.StatusCode)
 
-	time.Sleep(4 * time.Second)
+	time.Sleep(4*time.Second + 500*time.Millisecond)
 
 	resp, err = app.Test(httptest.NewRequest(fiber.MethodGet, "/success", nil))
 	utils.AssertEqual(t, nil, err)
@@ -258,7 +258,7 @@ func Test_Limiter_Sliding_Window_Custom_Storage_No_Skip_Choices(t *testing.T) {
 	utils.AssertEqual(t, nil, err)
 	utils.AssertEqual(t, 429, resp.StatusCode)
 
-	time.Sleep(4 * time.Second)
+	time.Sleep(4*time.Second + 500*time.Millisecond)
 
 	resp, err = app.Test(httptest.NewRequest(fiber.MethodGet, "/success", nil))
 	utils.AssertEqual(t, nil, err)
@@ -373,7 +373,7 @@ func Test_Limiter_Sliding_Window_Skip_Failed_Requests(t *testing.T) {
 	utils.AssertEqual(t, nil, err)
 	utils.AssertEqual(t, 429, resp.StatusCode)
 
-	time.Sleep(4 * time.Second)
+	time.Sleep(4*time.Second + 500*time.Millisecond)
 
 	resp, err = app.Test(httptest.NewRequest(fiber.MethodGet, "/success", nil))
 	utils.AssertEqual(t, nil, err)
@@ -412,7 +412,7 @@ func Test_Limiter_Sliding_Window_Custom_Storage_Skip_Failed_Requests(t *testing.
 	utils.AssertEqual(t, nil, err)
 	utils.AssertEqual(t, 429, resp.StatusCode)
 
-	time.Sleep(4 * time.Second)
+	time.Sleep(4*time.Second + 500*time.Millisecond)
 
 	resp, err = app.Test(httptest.NewRequest(fiber.MethodGet, "/success", nil))
 	utils.AssertEqual(t, nil, err)
@@ -533,7 +533,7 @@ func Test_Limiter_Sliding_Window_Skip_Successful_Requests(t *testing.T) {
 	utils.AssertEqual(t, nil, err)
 	utils.AssertEqual(t, 429, resp.StatusCode)
 
-	time.Sleep(4 * time.Second)
+	time.Sleep(4*time.Second + 500*time.Millisecond)
 
 	resp, err = app.Test(httptest.NewRequest(fiber.MethodGet, "/fail", nil))
 	utils.AssertEqual(t, nil, err)
@@ -574,7 +574,7 @@ func Test_Limiter_Sliding_Window_Custom_Storage_Skip_Successful_Requests(t *test
 	utils.AssertEqual(t, nil, err)
 	utils.AssertEqual(t, 429, resp.StatusCode)
 
-	time.Sleep(4 * time.Second)
+	time.Sleep(4*time.Second + 500*time.Millisecond)
 
 	resp, err = app.Test(httptest.NewRequest(fiber.MethodGet, "/fail", nil))
 	utils.AssertEqual(t, nil, err)