MAGETWO-49669: Impossible to set minimum and maximum lengths for customer address attributes without setting a validation type

Author: Sergey Semenov

app/code/Magento/Checkout/Block/Checkout/AttributeMerger.php

@@ -45,6 +45,7 @@ class AttributeMerger
         'alphanumeric' => 'validate-alphanum',
         'url' => 'validate-url',
         'email' => 'email2',
+        'length' => 'validate-length',
     ];
 
     /**

app/code/Magento/Eav/Model/Entity/Attribute/Frontend/AbstractFrontend.php

@@ -158,10 +158,10 @@ public function getClass()
 
         $textLengthValidateClasses = $this->getTextLengthValidateClasses();
         if (!empty($textLengthValidateClasses)) {
-            $out[] = implode(' ', $textLengthValidateClasses);
+            $out = array_merge($out, $textLengthValidateClasses);
         }
 
-        $out = !empty($out) ? trim(implode(' ', $out)) : '';
+        $out = !empty($out) ? implode(' ', array_unique(array_filter($out))) : '';
         return $out;
     }
 
@@ -191,6 +191,9 @@ protected function _getInputValidateClass()
                 case 'url':
                     $class = 'validate-url';
                     break;
+                case 'length':
+                    $class = 'validate-length';
+                    break;
                 default:
                     $class = false;
                     break;

app/code/Magento/Eav/Test/Unit/Model/Entity/Attribute/Frontend/DefaultFrontendTest.php

@@ -86,4 +86,36 @@ public function testGetClass()
         $this->assertContains('maximum-length-2', $result);
         $this->assertContains('validate-length', $result);
     }
+
+    public function testGetClassLength()
+    {
+        $attributeMock = $this->getMockBuilder('Magento\Eav\Model\Entity\Attribute\AbstractAttribute')
+            ->disableOriginalConstructor()
+            ->setMethods([
+                'getIsRequired',
+                'getFrontendClass',
+                'getValidateRules',
+            ])
+            ->getMock();
+        $attributeMock->expects($this->once())
+            ->method('getIsRequired')
+            ->willReturn(true);
+        $attributeMock->expects($this->once())
+            ->method('getFrontendClass')
+            ->willReturn('');
+        $attributeMock->expects($this->exactly(3))
+            ->method('getValidateRules')
+            ->willReturn([
+                'input_validation' => 'length',
+                'min_text_length' => 1,
+                'max_text_length' => 2,
+            ]);
+
+        $this->model->setAttribute($attributeMock);
+        $result = $this->model->getClass();
+
+        $this->assertContains('minimum-length-1', $result);
+        $this->assertContains('maximum-length-2', $result);
+        $this->assertContains('validate-length', $result);
+    }
 }