[tests] Fixed flaky test: test_input_filters openwisp#431

Closes  openwisp#431

Author: youhaveme9

openwisp_utils/admin_theme/static/admin/css/openwisp.css

@@ -73,8 +73,9 @@ See https://code.djangoproject.com/ticket/33878 */
   --object-tools-fg: var(--button-fg) !important;
   --object-tools-bg: var(--close-button-bg) !important;
   --object-tools-hover-bg: var(--close-button-hover-bg) !important;
-  --font-family-primary: "Roboto", "Lucida Grande", "DejaVu Sans",
-    "Bitstream Vera Sans", Verdana, Arial, sans-serif;
+  --font-family-primary:
+    "Roboto", "Lucida Grande", "DejaVu Sans", "Bitstream Vera Sans", Verdana,
+    Arial, sans-serif;
 }
 body {
   min-width: 320px;

openwisp_utils/admin_theme/static/drf-yasg/ow-drf-yasg.css

@@ -110,8 +110,9 @@ body::-webkit-scrollbar {
   text-transform: uppercase;
   font-weight: normal;
   margin: 0 5px;
-  font-family: "Roboto", "Lucida Grande", "DejaVu Sans", "Bitstream Vera Sans",
-    Verdana, Arial, sans-seri;
+  font-family:
+    "Roboto", "Lucida Grande", "DejaVu Sans", "Bitstream Vera Sans", Verdana,
+    Arial, sans-serif;
 }
 .swagger-ui .btn:hover {
   background-color: #999;

tests/test_project/tests/test_selenium.py

@@ -586,11 +586,20 @@ def test_input_filters(self):
 
         with self.subTest('Test SimpleInputFilter'):
             self.open(url)
-            input_field = self._get_simple_input_filter()
+
+            if "test_project/shelf/" not in self.web_driver.current_url:
+                self.open(url)
+
+            input_field = WebDriverWait(self.web_driver, 2).until(
+                EC.presence_of_element_located((By.CSS_SELECTOR, 'input[name=shelf]'))
+            )
+
             input_field.send_keys('Horror')
             self._get_filter_button().click()
             # Horror shelf is present
-            self.web_driver.find_element(By.XPATH, horror_result_xpath)
+            WebDriverWait(self.web_driver, 2).until(
+                EC.visibility_of_element_located((By.XPATH, horror_result_xpath))
+            )
             with self.assertRaises(NoSuchElementException):
                 # Factual shelf is absent
                 self.web_driver.find_element(By.XPATH, factual_result_xpath)

tests/test_project/tests/utils.py

@@ -124,9 +124,6 @@ def _get_logout_link(self):
     def _get_menu_backdrop(self):
         return self.web_driver.find_element(By.CSS_SELECTOR, '.menu-backdrop')
 
-    def _get_simple_input_filter(self):
-        return self.web_driver.find_element(By.CSS_SELECTOR, 'input[name=shelf]')
-
     def _get_input_filter(self):
         return self.web_driver.find_element(
             By.CSS_SELECTOR, 'input[name=books_type__exact]'