Added error css class to input when has error

Author: srtab

src/Fields/BoundField.php

@@ -121,10 +121,14 @@ protected function getValue()
 
     private function buildWidgetAttrs(array $attrs = array())
     {
-        $css_classes = implode(" ", $this->form->getCssClasses());
+        $css_classes = $this->form->getCssClasses();
+
+        if ($this->has_errors) {
+            $css_classes[] = $this->form->getErrorCssClass();
+        }
 
         if (!empty($css_classes)) {
-            $attrs['class'] = $css_classes;
+            $attrs['class'] = implode(" ", $css_classes);
         }
 
         if ($this->field->isRequired()) {

src/Forms/Form.php

@@ -49,6 +49,12 @@ abstract class Form implements ArrayAccess, Iterator, Countable
      */
     protected $css_classes = array();
 
+    /**
+     * Cass classes to be added to all widgets.
+     * @var array
+     */
+    protected $error_css_class = 'is-invalid';
+
     /**
      * Fields declared to this form.
      * @var array
@@ -104,6 +110,15 @@ public function getCssClasses()
         return $this->css_classes;
     }
 
+    /**
+     * Return error css class to be added on case of field error.
+     * @return array
+     */
+    public function getErrorCssClass()
+    {
+        return $this->error_css_class;
+    }
+
     /**
      * Special method to make errors accessible as a attribute.
      * @param  string $name Attribute name.

src/Widgets/Widget.php

@@ -96,15 +96,6 @@ public function valueFromData($data, $files, string $name)
         return array_key_exists($name, $data) ? $data[$name] : null;
     }
 
-    /**
-     * Return css classes to be added to each widget.
-     * @return string
-     */
-    private function buildCssClasses()
-    {
-        return implode(" ", $this->css_classes);
-    }
-
     /**
     * Return defined subwidget.
     *

tests/unit/Fields/BoundFieldTest.php

@@ -106,6 +106,23 @@ public function testToStringWithCssClasses()
         $this->assertXmlStringEqualsXmlString($expected, (string) $bound);
     }
 
+    public function testToStringWithErrors()
+    {
+        $form = $this->getMockBuilder(Form::class)
+                ->setMethods(array('hasErrors'))
+                ->getMockForAbstractClass();
+
+        $form->method('hasErrors')
+            ->will($this->returnValue(true));
+
+        $field = new CharField(["required" => true]);
+        $bound = new BoundField($form, $field, "name");
+
+        $expected = '<input type="text" id="id_name" name="name" required="required" class="is-invalid"/>';
+
+        $this->assertXmlStringEqualsXmlString($expected, (string) $bound);
+    }
+
     public function testLabelTag()
     {
         $field = new CharField(array("label" => "Label"));

tests/unit/Fields/FieldTest.php

@@ -45,7 +45,7 @@ public function testValidateWithRequiredValueEmpty()
     {
         $args = array("required" => true);
         $stub = $this->getMockForAbstractClass(Field::class, array($args));
-        $this->assertNull($stub->validate(""));
+        $stub->validate(null);
     }
 
     public function testRunValidatorsWithEmptyValue()