fixes #39: Enum::get() should return passed instance

Author: marc-mabe

src/MabeEnum/Enum.php

@@ -18,7 +18,7 @@ abstract class Enum
     /**
      * The selected value
      *
-     * @var null|boolean|int|float|string
+     * @var null|bool|int|float|string
      */
     private $value;
 
@@ -46,8 +46,8 @@ abstract class Enum
     /**
      * Constructor
      *
-     * @param null|boolean|int|float|string $value   The value to select
-     * @param int|null                      $ordinal The ordinal number of the value
+     * @param null|bool|int|float|string $value   The value to select
+     * @param int|null                   $ordinal The ordinal number of the value
      */
     final private function __construct($value, $ordinal = null)
     {
@@ -78,7 +78,7 @@ final private function __clone()
     /**
      * Get the current selected value
      *
-     * @return null|boolean|int|float|string
+     * @return null|bool|int|float|string
      */
     final public function getValue()
     {
@@ -124,25 +124,38 @@ final public function getOrdinal()
      * Compare this enum against another enum and check if it's the same value
      *
      * @param mixed $value
-     * @return boolean
+     * @return bool
      */
     final public function is($enum)
     {
         return $this->value === $enum || ($enum instanceof static && $this->value === $enum->getValue());
     }
 
     /**
-     * Get an enum of the given value
+     * Get an enum of the given value or instance
      *
-     * @param static|null|boolean|int|float|string $value
+     * On passing an extended instance the instance will be returned if the value
+     * is inherited by the called class or if $tradeExtendedAsUnknown is disabled
+     * else an InvalidArgumentException will be thrown.
+     *
+     * @param static|null|bool|int|float|string $value
+     * @param bool                              $tradeExtendedAsUnknown
      * @return static
      * @throws InvalidArgumentException On an unknwon or invalid value
      * @throws LogicException           On ambiguous constant values
      */
-    final public static function get($value)
+    final public static function get($value, $tradeExtendedAsUnknown = true)
     {
         if ($value instanceof static) {
-            $value = $value->getValue();
+            if ($tradeExtendedAsUnknown && !defined(get_called_class() . '::' . $value->getName())) {
+                throw new InvalidArgumentException(sprintf(
+                    "%s::%s is not inherited from %s",
+                    get_class($value),
+                    $value->getName(),
+                    get_called_class()
+                ));
+            }
+            return $value;
         }
 
         $class     = get_called_class();

tests/MabeEnumTest/EnumTest.php

@@ -98,28 +98,35 @@ public function testGetByInstance()
         $this->assertSame($enum1, $enum2);
     }
 
-    public function testGetByInheritInstance()
+    public function testGetByExtendedInstanceOfKnownValue()
     {
-        $enumInherit = EnumInheritance::get(EnumInheritance::ONE);
-        $enum1       = EnumBasic::get(EnumBasic::ONE);
-        $enum2       = EnumBasic::get($enumInherit);
-        $this->assertSame($enum1, $enum2);
+        $enum = EnumInheritance::get(EnumInheritance::ONE);
+        $this->assertSame($enum, EnumBasic::get($enum));
+    }
+
+    public function testGetByExtendedInstanceOfUnknownValueExplicitAllowed()
+    {
+        $enum = EnumInheritance::get(EnumInheritance::INHERITANCE);
+        $this->assertSame($enum, EnumBasic::get($enum, false));
     }
 
-    public function testGetByInheritInstanceThrowsInvalidArgumentExceptionOnUnknownValue()
+    public function testGetByExtendedInstanceOfUnknownValueThrowsInvalidArgumentException()
     {
-        $enumInherit = EnumInheritance::get(EnumInheritance::INHERITANCE);
+        $enum = EnumInheritance::get(EnumInheritance::INHERITANCE);
 
-        $this->setExpectedException('InvalidArgumentException');
-        EnumBasic::get($enumInherit);
+        $this->setExpectedException(
+            'InvalidArgumentException',
+            'MabeEnumTest\TestAsset\EnumInheritance::INHERITANCE is not inherited from MabeEnumTest\TestAsset\EnumBasic'
+        );
+        EnumBasic::get($enum, true);
     }
 
     public function testGetByInstanceOfDifferentBaseThrowsInvalidArgumentException()
     {
-        $enumDiff = EnumBasic2::get(EnumBasic2::ONE);
+        $enum = EnumBasic2::get(EnumBasic2::ONE);
 
         $this->setExpectedException('InvalidArgumentException');
-        EnumBasic::get($enumDiff);
+        EnumBasic::get($enum);
     }
 
     public function testGetAllValues()