diff --git a/README.md b/README.md
index d2b98537..52bfacfb 100644
--- a/README.md
+++ b/README.md
@@ -255,6 +255,9 @@ GUMP::add_validator("equals_string", function($field, array $input, array $param
     return $value === $params;
 }, 'Field {field} does not equal to {param}.');
 
+// You might want to check whether a validator exists first
+GUMP::has_validator($rule);
+
 /**
  * @param string $value Value
  * @param array  $param Filter parameters (optional)
@@ -264,6 +267,9 @@ GUMP::add_validator("equals_string", function($field, array $input, array $param
 GUMP::add_filter("upper", function($value, array $params = []) {
     return strtoupper($value);
 });
+
+// You might want to check whether a filter first already
+GUMP::has_filter($rule);
 ```
 
 Alternately, you can simply create your own class that extends GUMP. You only have to have in mind:
diff --git a/gump.class.php b/gump.class.php
index 866cc98b..6f3eefe7 100644
--- a/gump.class.php
+++ b/gump.class.php
@@ -254,6 +254,32 @@ public static function add_filter(string $rule, callable $callback)
         self::$filter_methods[$rule] = $callback;
     }
 
+    /**
+     * Checks if a validator exists.
+     *
+     * @param string $rule
+     *
+     * @return bool
+     */
+    public static function has_validator(string $rule)
+    {
+        return method_exists(__CLASS__, self::validator_to_method($rule)) || isset(self::$validation_methods[$rule]);
+    }
+
+    /**
+     * Checks if a filter exists.
+     *
+     * @param string $filter
+     *
+     * @return bool
+     */
+    public static function has_filter(string $filter)
+    {
+        return method_exists(__CLASS__, self::filter_to_method($filter))
+            || isset(self::$filter_methods[$filter])
+            || function_exists($filter);
+    }
+
     /**
      * Helper method to extract an element from an array safely
      *
@@ -1950,27 +1976,4 @@ protected function validate_valid_array_size_equal($field, array $input, array $
     {
         return !(!is_array($input[$field]) || count($input[$field]) != $params[0]);
     }
-
-    /**
-     * Checks if a validator method exists for a given rule.
-     *
-     * @param string $rule
-     * @return bool
-     */
-    public static function has_validator(string $rule): bool
-    {
-        return method_exists(__CLASS__, self::validator_to_method($rule)) || isset(self::$validation_methods[$rule]);
-    }
-
-    /**
-     * Checks if a filter method exists for a given filter.
-     * @param string $filter
-     * @return bool
-     */
-    public static function has_filter(string $filter): bool
-    {
-        return method_exists(__CLASS__, self::filter_to_method($filter))
-            || isset(self::$filter_methods[$filter])
-            || function_exists($filter);
-    }
 }
diff --git a/tests/StaticHasFilterTest.php b/tests/StaticHasFilterTest.php
index 6c458392..97285dea 100644
--- a/tests/StaticHasFilterTest.php
+++ b/tests/StaticHasFilterTest.php
@@ -6,40 +6,38 @@
 
 class StaticHasFilterTest extends BaseTestCase
 {
-    public function testHasFilterWhenExists(): void
+    public function dataOfExistingRules()
     {
-        $filterRules = [
+        return [
             // There are native filters
-            'noise_words',
-            'rmpunctuation',
-            'urlencode',
-            'htmlencode',
-            'sanitize_email',
-            'sanitize_numbers',
-            'sanitize_floats',
-            'sanitize_string',
-            'boolean',
-            'basic_tags',
-            'whole_number',
-            'ms_word_characters',
-            'lower_case',
-            'upper_case',
-            'slug',
+            ['noise_words'],
+            ['upper_case'],
+            ['slug'],
             // These are built-in functions
-            'trim',
-            'strtoupper',
-            'strtolower',
-            'intval',
-            'floatval',
+            ['trim'],
+            ['strtoupper'],
         ];
+    }
+
+    /**
+     * @dataProvider dataOfExistingRules
+     */
+    public function testHasFilterWhenExists(string $rule)
+    {
+        $this->assertTrue(GUMP::has_filter($rule));
+    }
+
+    public function testHasFilterWithCustomRule(): void
+    {
+        GUMP::add_filter('test', function($value, array $params = []) {
+            return strtoupper($value);
+        });
 
-        foreach ($filterRules as $filterRule) {
-            $this->assertTrue(GUMP::has_filter($filterRule));
-        }
+        $this->assertTrue(GUMP::has_filter('test'));
     }
 
     public function testHasFilterWhenNotExists(): void
     {
-        $this->assertFalse(GUMP::has_filter('custom_filter'));
+        $this->assertFalse(GUMP::has_filter('test'));
     }
-}
\ No newline at end of file
+}
diff --git a/tests/StaticHasValidatorTest.php b/tests/StaticHasValidatorTest.php
index 023cdcd4..60ba2804 100644
--- a/tests/StaticHasValidatorTest.php
+++ b/tests/StaticHasValidatorTest.php
@@ -6,61 +6,35 @@
 
 class StaticHasValidatorTest extends BaseTestCase
 {
-    public function testHasValidatorWhenExists(): void
+    public function dataOfExistingRules()
     {
-        $validationRules = [
-            'required',
-            'contains',
-            'contains_list',
-            'doesnt_contain_list',
-            'boolean',
-            'valid_email',
-            'max_len',
-            'min_len',
-            'exact_len',
-            'between_len',
-            'alpha',
-            'alpha_numeric',
-            'alpha_dash',
-            'alpha_numeric_dash',
-            'alpha_numeric_space',
-            'alpha_space',
-            'numeric',
-            'integer',
-            'float',
-            'valid_url',
-            'url_exists',
-            'valid_ip',
-            'valid_ipv4',
-            'valid_ipv6',
-            'valid_cc',
-            'valid_name',
-            'street_address',
-            'iban',
-            'date',
-            'min_age',
-            'max_numeric',
-            'min_numeric',
-            'starts',
-            'required_file',
-            'extension',
-            'equalsfield',
-            'guidv4',
-            'phone_number',
-            'regex',
-            'valid_json_string',
-            'valid_array_size_greater',
-            'valid_array_size_lesser',
-            'valid_array_size_equal',
+        return [
+            ['required'],
+            ['contains'],
+            ['regex'],
+            ['valid_array_size_equal'],
         ];
+    }
+
+    /**
+     * @dataProvider dataOfExistingRules
+     */
+    public function testHasValidatorWhenExists(string $rule)
+    {
+        $this->assertTrue(GUMP::has_validator($rule));
+    }
+
+    public function testHasValidatorWithCustomRule()
+    {
+        GUMP::add_validator("equals_string", function($field, array $input, array $params, $value) {
+            return $value === $params;
+        }, 'Field {field} does not equal to {param}.');
 
-        foreach ($validationRules as $rule) {
-            $this->assertTrue(GUMP::has_validator($rule));
-        }
+        $this->assertTrue(GUMP::has_validator('equals_string'));
     }
 
-    public function testHasValidatorWhenNotExists(): void
+    public function testHasValidatorWhenDoesntExist()
     {
-        $this->assertFalse(GUMP::has_validator('custom_rule'));
+        $this->assertFalse(GUMP::has_validator('equals_string'));
     }
-}
\ No newline at end of file
+}