Added optional support for brotli compression (#983)

* Added optional support for brotli compression.

* Ignore import error for coverage purposes.

kombu/compression.py

@@ -76,3 +76,12 @@ register(zlib.compress,
 register(bz2.compress,
          bz2.decompress,
          'application/x-bz2', aliases=['bzip2', 'bzip'])
+
+try:
+    import brotli
+except ImportError:  # pragma: no cover
+    pass
+else:
+    register(brotli.compress,
+             brotli.decompress,
+             'application/x-brotli', aliases=['brotli'])

requirements/extras/brotli.txt

@@ -0,0 +1,2 @@
+brotlipy>=0.7.0;python_implementation=="PyPy"
+brotli>=1.0.0;python_implementation=="CPython"

requirements/test-ci.txt

@@ -9,4 +9,5 @@ msgpack-python>0.2.0
 -r extras/consul.txt
 -r extras/librabbitmq.txt
 -r extras/zookeeper.txt
+-r extras/brotli.txt
 sqlalchemy

t/unit/test_compression.py

@@ -1,5 +1,7 @@
 from __future__ import absolute_import, unicode_literals
 
+import pytest
+
 from kombu import compression
 
 
@@ -11,6 +13,11 @@ class test_compression:
     def test_encoders__bz2(self):
         assert 'application/x-bz2' in compression.encoders()
 
+    def test_encoders__brotli(self):
+        pytest.importorskip('brotli')
+
+        assert 'application/x-brotli' in compression.encoders()
+
     def test_compress__decompress__zlib(self):
         text = b'The Quick Brown Fox Jumps Over The Lazy Dog'
         c, ctype = compression.compress(text, 'zlib')
@@ -24,3 +31,12 @@ class test_compression:
         assert text != c
         d = compression.decompress(c, ctype)
         assert d == text
+
+    def test_compress__decompress__brotli(self):
+        pytest.importorskip('brotli')
+
+        text = b'The Brown Quick Fox Over The Lazy Dog Jumps'
+        c, ctype = compression.compress(text, 'brotli')
+        assert text != c
+        d = compression.decompress(c, ctype)
+        assert d == text