Added support for lzma compression (#984)

* Added support for lzma compression.

* Ignore branch.

kombu/compression.py

@@ -6,6 +6,15 @@ from kombu.utils.encoding import ensure_bytes
 import bz2
 import zlib
 
+try:
+    import lzma
+except ImportError:  # pragma: no cover
+    # TODO: Drop fallback to backports once we drop Python 2.7 support
+    try:
+        from backports import lzma
+    except ImportError:  # pragma: no cover
+        lzma = None
+
 _aliases = {}
 _encoders = {}
 _decoders = {}
@@ -85,3 +94,9 @@ else:
     register(brotli.compress,
              brotli.decompress,
              'application/x-brotli', aliases=['brotli'])
+
+# TODO: Drop condition once we drop Python 2.7 support
+if lzma:  # pragma: no cover
+    register(lzma.compress,
+             lzma.decompress,
+             'application/x-lzma', aliases=['lzma', 'xz'])

requirements/extras/lzma.txt

@@ -0,0 +1 @@
+backports.lzma;python_version<"3.3"

requirements/test-ci-py2.txt

@@ -1 +1,2 @@
 -r extras/sqs.txt
+-r extras/lzma.txt

t/unit/test_compression.py

@@ -18,6 +18,16 @@ class test_compression:
 
         assert 'application/x-brotli' in compression.encoders()
 
+    def test_encoders__lzma(self):
+        pytest.importorskip('lzma')
+
+        assert 'application/x-lzma' in compression.encoders()
+
+    def test_encoders__backports_lzma(self):
+        pytest.importorskip('backports.lzma')
+
+        assert 'application/x-lzma' 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')
@@ -37,6 +47,21 @@ class test_compression:
 
         text = b'The Brown Quick Fox Over The Lazy Dog Jumps'
         c, ctype = compression.compress(text, 'brotli')
+
+    def test_compress__decompress__lzma(self):
+        pytest.importorskip('lzma')
+
+        text = b'The Brown Quick Fox Over The Lazy Dog Jumps'
+        c, ctype = compression.compress(text, 'lzma')
+        assert text != c
+        d = compression.decompress(c, ctype)
+        assert d == text
+
+    def test_compress__decompress__backports_lzma(self):
+        pytest.importorskip('backports.lzma')
+
+        text = b'The Brown Quick Fox Over The Lazy Dog Jumps'
+        c, ctype = compression.compress(text, 'lzma')
         assert text != c
         d = compression.decompress(c, ctype)
         assert d == text