Fixed bug where EnumType::asNullable() would reject null

src/Type/EnumType.php

@@ -13,6 +13,7 @@
 
 use EventEngine\JsonSchema\AnnotatedType;
 use EventEngine\JsonSchema\JsonSchema;
+use EventEngine\JsonSchema\Type;
 
 class EnumType implements AnnotatedType
 {
@@ -41,4 +42,16 @@ public function toArray(): array
             'enum' => $this->entries,
         ], $this->annotations());
     }
+
+    public function asNullable(): Type
+    {
+        $cp = clone $this;
+
+        $this->assertTypeCanBeConvertedToNullableType($cp);
+
+        $cp->type = [$cp->type, JsonSchema::TYPE_NULL];
+        $cp->entries[] = null;
+
+        return $cp;
+    }
 }

src/Type/NullableType.php

@@ -20,16 +20,25 @@ public function asNullable(): Type
     {
         $cp = clone $this;
 
+        $this->assertTypeCanBeConvertedToNullableType($cp);
+
+        $cp->type = [$cp->type, JsonSchema::TYPE_NULL];
+
+        return $cp;
+    }
+
+    protected function assertTypeCanBeConvertedToNullableType(Type $cp): void
+    {
         if (! isset($cp->type)) {
-            throw new \RuntimeException('Type cannot be converted to nullable type. No json schema type set for ' . \get_class($this));
+            throw new \RuntimeException(
+                'Type cannot be converted to nullable type. No json schema type set for ' . \get_class($this)
+            );
         }
 
         if (! \is_string($cp->type)) {
-            throw new \RuntimeException('Type cannot be converted to nullable type. JSON schema type is not a string');
+            throw new \RuntimeException(
+                'Type cannot be converted to nullable type. JSON schema type is not a string'
+            );
         }
-
-        $cp->type = [$cp->type, JsonSchema::TYPE_NULL];
-
-        return $cp;
     }
 }

tests/Type/EnumTypeTest.php

@@ -0,0 +1,50 @@
+<?php
+/**
+ * This file is part of the event-engine/php-json-schema.
+ * (c) 2017-2019 prooph software GmbH <[email protected]>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+declare(strict_types=1);
+
+namespace EventEngineTest\JsonSchema\Type;
+
+use EventEngine\JsonSchema\Type\EnumType;
+use EventEngineTest\JsonSchema\BasicTestCase;
+
+final class EnumTypeTest extends BasicTestCase
+{
+    /**
+     * @test
+     */
+    public function it_creates_enum_type()
+    {
+        $enumType = new EnumType('a', 'b');
+
+        $this->assertEquals(
+            [
+                'type' => 'string',
+                'enum' => ['a', 'b'],
+            ],
+            $enumType->toArray()
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function it_creates_nullable_enum_type()
+    {
+        $enumType = (new EnumType('a', 'b'))->asNullable();
+
+        $this->assertEquals(
+            [
+                'type' => ['string', 'null'],
+                'enum' => ['a', 'b', null]
+            ],
+            $enumType->toArray()
+        );
+    }
+}