Remove header if there is no more encoding value

CHANGELOG.md

@@ -10,6 +10,10 @@
 
 - AddPathPlugin no longer add prefix multiple times if a request is restarted - it now only adds the prefix if that request chain has not yet passed through the AddPathPlugin
 
+### Fixed
+
+- Decoder plugin will now remove header when there is no more encoding, instead of setting to an empty array
+
 ## 1.7.0 - 2017-11-30
 
 ### Added 

spec/Plugin/DecoderPluginSpec.php

@@ -38,7 +38,7 @@ function it_decodes(RequestInterface $request, ResponseInterface $response, Stre
         $response->getHeader('Transfer-Encoding')->willReturn(['chunked']);
         $response->getBody()->willReturn($stream);
         $response->withBody(Argument::type('Http\Message\Encoding\DechunkStream'))->willReturn($response);
-        $response->withHeader('Transfer-Encoding', [])->willReturn($response);
+        $response->withoutHeader('Transfer-Encoding')->willReturn($response);
         $response->hasHeader('Content-Encoding')->willReturn(false);
 
         $stream->isReadable()->willReturn(true);
@@ -61,7 +61,7 @@ function it_decodes_gzip(RequestInterface $request, ResponseInterface $response,
         $response->getHeader('Content-Encoding')->willReturn(['gzip']);
         $response->getBody()->willReturn($stream);
         $response->withBody(Argument::type('Http\Message\Encoding\GzipDecodeStream'))->willReturn($response);
-        $response->withHeader('Content-Encoding', [])->willReturn($response);
+        $response->withoutHeader('Content-Encoding')->willReturn($response);
 
         $stream->isReadable()->willReturn(true);
         $stream->isWritable()->willReturn(false);
@@ -83,7 +83,7 @@ function it_decodes_deflate(RequestInterface $request, ResponseInterface $respon
         $response->getHeader('Content-Encoding')->willReturn(['deflate']);
         $response->getBody()->willReturn($stream);
         $response->withBody(Argument::type('Http\Message\Encoding\DecompressStream'))->willReturn($response);
-        $response->withHeader('Content-Encoding', [])->willReturn($response);
+        $response->withoutHeader('Content-Encoding')->willReturn($response);
 
         $stream->isReadable()->willReturn(true);
         $stream->isWritable()->willReturn(false);

src/Plugin/DecoderPlugin.php

@@ -107,7 +107,11 @@ private function decodeOnEncodingHeader($headerName, ResponseInterface $response
                 $response = $response->withBody($stream);
             }
 
-            $response = $response->withHeader($headerName, $newEncodings);
+            if (\count($newEncodings) > 0) {
+                $response = $response->withHeader($headerName, $newEncodings);
+            } else {
+                $response = $response->withoutHeader($headerName);
+            }
         }
 
         return $response;