Implemented memberOrNullByKey. Relates to #18.

src/AbstractMultiton.php

@@ -56,6 +56,23 @@ final public static function memberByKeyWithDefault(
         );
     }
 
+    /**
+     * Returns a single member by string key. Additionally returns null if the
+     * supplied key is null.
+     *
+     * @param string|null  $key             The string key associated with the member, or null.
+     * @param boolean|null $isCaseSensitive True if the search should be case sensitive.
+     *
+     * @return MultitonInterface|null                      The member associated with the given string key, or null if the supplied key is null.
+     * @throws Exception\UndefinedMemberExceptionInterface If no associated member is found.
+     */
+    final public static function memberOrNullByKey(
+        $key,
+        $isCaseSensitive = null
+    ) {
+        return static::memberOrNullBy('key', $key, $isCaseSensitive);
+    }
+
     /**
      * Returns a single member by comparison with the result of an accessor
      * method.

src/AbstractValueMultiton.php

@@ -55,7 +55,8 @@ final public static function memberByValueWithDefault(
     }
 
     /**
-     * Returns a single member by value.
+     * Returns a single member by value. Additionally returns null if the
+     * supplied value is null.
      *
      * @param scalar|null  $value           The value associated with the member, or null.
      * @param boolean|null $isCaseSensitive True if the search should be case sensitive.

test/suite/AbstractMultitonTest.php

@@ -69,6 +69,20 @@ public function testMemberByKeyWithDefault()
         $this->assertNull(ValidMultiton::memberByKeyWithDefault('qux'));
     }
 
+    public function testMemberOrNullByKey()
+    {
+        $this->assertSame(ValidMultiton::FOO(), ValidMultiton::memberOrNullByKey('FOO'));
+        $this->assertSame(ValidMultiton::BAR(), ValidMultiton::memberOrNullByKey('BAR'));
+        $this->assertSame(ValidMultiton::FOO(), ValidMultiton::memberOrNullByKey('Foo', false));
+        $this->assertNull(ValidMultiton::memberOrNullByKey(null));
+    }
+
+    public function testMemberOrNullByKeyFailureUndefined()
+    {
+        $this->setExpectedException('Eloquent\Enumeration\Exception\UndefinedMemberException');
+        ValidMultiton::memberOrNullByKey('DOOM');
+    }
+
     public function testMemberBy()
     {
         $this->assertSame(array(), ValidMultiton::calls());

test/suite/AbstractValueMultitonTest.php

@@ -69,6 +69,20 @@ public function testMemberByKeyWithDefault()
         $this->assertNull(ValidValueMultiton::memberByKeyWithDefault('qux'));
     }
 
+    public function testMemberOrNullByKey()
+    {
+        $this->assertSame(ValidValueMultiton::FOO(), ValidValueMultiton::memberOrNullByKey('FOO'));
+        $this->assertSame(ValidValueMultiton::BAR(), ValidValueMultiton::memberOrNullByKey('BAR'));
+        $this->assertSame(ValidValueMultiton::FOO(), ValidValueMultiton::memberOrNullByKey('Foo', false));
+        $this->assertNull(ValidValueMultiton::memberOrNullByKey(null));
+    }
+
+    public function testMemberOrNullByKeyFailureUndefined()
+    {
+        $this->setExpectedException('Eloquent\Enumeration\Exception\UndefinedMemberException');
+        ValidValueMultiton::memberOrNullByKey('DOOM');
+    }
+
     public function testMemberBy()
     {
         $this->assertSame(array(), ValidValueMultiton::calls());