Merge branch 'hotfix/101'

Close #101
Fixes #100

Author: weierophinney

CHANGELOG.md

@@ -18,7 +18,10 @@ All notable changes to this project will be documented in this file, in reverse
 
 ### Fixed
 
-- Nothing.
+- [#101](https://github.com/zendframework/zend-diactoros/pull/101) fixes the
+  `withHeader()` implementation to ensure that if the header existed previously
+  but using a different casing strategy, the previous version will be removed
+  in the cloned instance.
 
 ## 1.2.0 - 2015-11-24
 

src/MessageTrait.php

@@ -204,6 +204,9 @@ public function withHeader($header, $value)
         $normalized = strtolower($header);
 
         $new = clone $this;
+        if ($new->hasHeader($header)) {
+            unset($new->headers[$new->headerNames[$normalized]]);
+        }
         $new->headerNames[$normalized] = $header;
         $new->headers[$header]         = $value;
 

test/MessageTraitTest.php

@@ -175,6 +175,14 @@ public function testWithHeaderRaisesExceptionForInvalidValueType($value)
         $message = $this->message->withHeader('X-Foo', $value);
     }
 
+    public function testWithHeaderReplacesDifferentCapitalization()
+    {
+        $this->message = $this->message->withHeader('X-Foo', ['foo']);
+        $new = $this->message->withHeader('X-foo', ['bar']);
+        $this->assertEquals(['bar'], $new->getHeader('x-foo'));
+        $this->assertEquals(['X-foo' => ['bar']], $new->getHeaders());
+    }
+
     /**
      * @dataProvider invalidGeneralHeaderValues
      */