Add basic zlib input stream test

test/ZlibInputStreamTest.php

@@ -0,0 +1,44 @@
+<?php
+
+namespace Amp\ByteStream\Test;
+
+use Amp\ByteStream\InMemoryStream;
+use Amp\ByteStream\IteratorStream;
+use Amp\ByteStream\ZlibInputStream;
+use Amp\Delayed;
+use Amp\Loop;
+use Amp\PHPUnit\TestCase;
+use Amp\Producer;
+
+class ZlibInputStreamTest extends TestCase {
+    public function testRead() {
+        Loop::run(function () {
+            $file1 = __DIR__ . "/fixtures/foobar.txt";
+            $file2 = __DIR__ . "/fixtures/foobar.txt.gz";
+
+            $stream = new IteratorStream(new Producer(function (callable $emit) use ($file2) {
+                $content = \file_get_contents($file2);
+
+                while ($content !== "") {
+                    yield $emit($content[0]);
+                    $content = \substr($content, 1);
+                }
+            }));
+
+            $gzStream = new ZlibInputStream($stream, \ZLIB_ENCODING_GZIP);
+
+            $buffer = "";
+            while (($chunk = yield $gzStream->read()) !== null) {
+                $buffer .= $chunk;
+            }
+
+            $this->assertSame(\file_get_contents($file1), $buffer);
+        });
+    }
+
+    public function testInvalidEncoding() {
+        $this->expectException(\Error::class);
+
+        new ZlibInputStream(new InMemoryStream(""), 1337);
+    }
+}

test/fixtures/foobar.txt

@@ -0,0 +1 @@
+foobar content