Do not pass arguments using default values to the Filter\fun function (#89)

* Do not use the arguments that were not specified intentionally by the user for the read/write filters

* Do not rely on the number of arguments passed to the FilteredStream class to initialize the stream filter

* Add unit tests

Author: ste93cry

Diff for: spec/Encoding/FilteredStreamStubSpec.php

@@ -0,0 +1,69 @@
+<?php
+
+namespace spec\Http\Message\Encoding;
+
+use Http\Message\Encoding\FilteredStream;
+use PhpSpec\ObjectBehavior;
+use Psr\Http\Message\StreamInterface;
+
+class FilteredStreamStubSpec extends ObjectBehavior
+{
+    function it_throws_during_instantiation_with_invalid_read_filter_options(StreamInterface $stream)
+    {
+        $this->beAnInstanceOf('spec\Http\Message\Encoding\FilteredStreamStub');
+        $this->beConstructedWith($stream, 'foo');
+        $this->shouldThrow('RuntimeException')->duringInstantiation();
+    }
+
+    function it_throws_during_instantiation_with_invalid_write_filter_options(StreamInterface $stream)
+    {
+        $this->beAnInstanceOf('spec\Http\Message\Encoding\FilteredStreamStub');
+        $this->beConstructedWith($stream, null, 'foo');
+        $this->shouldThrow('RuntimeException')->duringInstantiation();
+    }
+
+    function let(StreamInterface $stream)
+    {
+        $this->beAnInstanceOf('spec\Http\Message\Encoding\FilteredStreamStub');
+        $this->beConstructedWith($stream);
+    }
+
+    function it_reads()
+    {
+        // "This is a test stream" | base64_encode
+        $stream = new MemoryStream('This is a test stream');
+        $this->beConstructedWith($stream);
+
+        $this->read(4)->shouldReturn('VGhp');
+    }
+
+    function it_gets_content()
+    {
+        // "This is a test stream" | base64_encode
+        $stream = new MemoryStream('This is a test stream');
+        $this->beConstructedWith($stream);
+
+        $this->getContents()->shouldReturn('VGhpcyBpcyBhIHRlc3Qgc3RyZWFt');
+    }
+
+    function it_does_not_know_the_content_size()
+    {
+        $stream = new MemoryStream(gzencode('This is a test stream'));
+        $this->beConstructedWith($stream);
+
+        $this->getSize()->shouldBeNull();
+    }
+}
+
+class FilteredStreamStub extends FilteredStream
+{
+    protected function readFilter()
+    {
+        return 'convert.base64-encode';
+    }
+
+    protected function writeFilter()
+    {
+        return 'convert.base64-encode';
+    }
+}

Diff for: src/Encoding/FilteredStream.php

@@ -57,11 +57,18 @@ abstract class FilteredStream implements StreamInterface
      */
     public function __construct(StreamInterface $stream, $readFilterOptions = null, $writeFilterOptions = null)
     {
-        $this->readFilterCallback = Filter\fun($this->readFilter(), $readFilterOptions);
-        $this->writeFilterCallback = Filter\fun($this->writeFilter(), $writeFilterOptions);
+        if (null !== $readFilterOptions) {
+            $this->readFilterCallback = Filter\fun($this->readFilter(), $readFilterOptions);
+        } else {
+            $this->readFilterCallback = Filter\fun($this->readFilter());
+        }
 
         if (null !== $writeFilterOptions) {
+            $this->writeFilterCallback = Filter\fun($this->writeFilter(), $writeFilterOptions);
+
             @trigger_error('The $writeFilterOptions argument is deprecated since version 1.5 and will be removed in 2.0.', E_USER_DEPRECATED);
+        } else {
+            $this->writeFilterCallback = Filter\fun($this->writeFilter());
         }
 
         $this->stream = $stream;