Fixing validation of min and max value in field config entity. Adding test unit for this

Closes #3052663

core/lib/Drupal/Core/Field/Plugin/Field/FieldType/NumericItemBase.php

@@ -33,6 +33,7 @@ public function fieldSettingsForm(array $form, FormStateInterface $form_state) {
       '#type' => 'number',
       '#title' => $this->t('Minimum'),
       '#default_value' => $settings['min'],
+      '#element_validate' => [[static::class, 'validateMinMax']],
       '#description' => $this->t('The minimum value that should be allowed in this field. Leave blank for no minimum.'),
     ];
     $element['max'] = [
@@ -59,6 +60,29 @@ public function fieldSettingsForm(array $form, FormStateInterface $form_state) {
     return $element;
   }
 
+  /**
+   * Validate min and max value ensuring that min always is less than max value.
+   *
+   * @param array $element
+   *   The element to be validated.
+   * @param \Drupal\Core\Form\FormStateInterface $form_state
+   *   The form state instance.
+   * @param array $complete_form
+   *   The form completed instance.
+   */
+  public static function validateMinMax(array &$element, FormStateInterface &$form_state, array &$complete_form): void {
+    $settingsValue = $form_state->getValue('settings');
+
+    if (empty($settingsValue['min']) || empty($settingsValue['max'])) {
+      return;
+    }
+
+    // Ensure that the input is less than the #max property, if set.
+    if ((float) $settingsValue['min'] > (float) $settingsValue['max']) {
+      $form_state->setError($element, t('Min must be lower than or equal to %max.', ['%max' => $settingsValue['max']]));
+    }
+  }
+
   /**
    * {@inheritdoc}
    */
@@ -85,7 +109,12 @@ public function getConstraints() {
         'value' => [
           'Range' => [
             'min' => $min,
-            'minMessage' => $this->t('%name: the value may be no less than %min.', ['%name' => $label, '%min' => $min]),
+            'minMessage' => $this->t('%name: the value may be no less than %min.',
+              [
+                '%name' => $label,
+                '%min' => $min,
+              ]
+            ),
           ],
         ],
       ]);