ENHANCEMENT setEmptyString option on EditableDropdown

closes #17

code/model/editableformfields/EditableDropdown.php

@@ -1,12 +1,15 @@
 <?php
+
 /**
  * EditableDropdown
  *
  * Represents a modifiable dropdown (select) box on a form
  *
+ * @property bool $UseEmptyString
+ * @property string $EmptyString
+ *
  * @package userforms
  */
-
 class EditableDropdown extends EditableMultipleOptionField
 {
 
@@ -14,6 +17,11 @@ class EditableDropdown extends EditableMultipleOptionField
 
     private static $plural_name = 'Dropdowns';
 
+    private static $db = array(
+        'UseEmptyString' => 'Boolean',
+        'EmptyString' => 'Varchar(255)',
+    );
+
     /**
      * @return FieldList
      */
@@ -21,6 +29,18 @@ class EditableDropdown extends EditableMultipleOptionField
     {
         $fields = parent::getCMSFields();
 
+        $fields->addFieldToTab(
+            'Root.Main',
+            CheckboxField::create('UseEmptyString')
+                ->setTitle('Set default empty string')
+        );
+
+        $fields->addFieldToTab(
+            'Root.Main',
+            TextField::create('EmptyString')
+                ->setTitle('Empty String')
+        );
+
         $fields->removeByName('Default');
 
         return $fields;
@@ -35,6 +55,10 @@ class EditableDropdown extends EditableMultipleOptionField
             ->setFieldHolderTemplate('UserFormsField_holder')
             ->setTemplate('UserFormsDropdownField');
 
+        if ($this->UseEmptyString) {
+            $field->setEmptyString(($this->EmptyString) ? $this->EmptyString : '');
+        }
+
         // Set default
         $defaultOption = $this->getDefaultOptions()->first();
         if ($defaultOption) {

tests/EditableDropdownTest.php

@@ -0,0 +1,42 @@
+<?php
+
+/**
+ * Tests the {@see EditableDropdown} class
+ */
+class EditableDropdownTest extends SapphireTest
+{
+
+    public static $fixture_file = 'userforms/tests/EditableFormFieldTest.yml';
+
+    public function setUp()
+    {
+        parent::setUp();
+    }
+
+    /**
+     * Tests that the field sets the empty string if set
+     */
+    public function testFormField()
+    {
+        if (!$dropdown = EditableDropdown::get()->filter('UseEmptyString', true)->first()) {
+            $dropdown = $this->objFromFixture('EditableDropdown', 'basic-dropdown');
+
+            $dropdown->UseEmptyString = true;
+            $dropdown->EmptyString = 'My Default Empty String';
+            $dropdown->write();
+        }
+
+        $field = $dropdown->getFormField();
+        $this->assertEquals($field->getEmptyString(), 'My Default Empty String');
+
+        $alternateDropdown = $this->objFromFixture('EditableDropdown', 'department-dropdown');
+        $formField = $alternateDropdown->getFormField();
+        $this->assertFalse($formField->getHasEmptyDefault());
+
+        $alternateDropdown->UseEmptyString = true;
+        $alternateDropdown->write();
+        $this->assertEquals($formField->getEmptyString(), '');
+
+    }
+
+}