Autoformat py files using Black (#105)

* Autoformat all py files using Black
* Fix lint errors
* Fix indentation errors (https://travis-ci.org/httplib2/httplib2/jobs/408136309)
* Refactor three test cases and exclude them on on Travis py27/pypy
diff --git a/tests/test_encoding.py b/tests/test_encoding.py
index df991a1..c7eead5 100644
--- a/tests/test_encoding.py
+++ b/tests/test_encoding.py
@@ -6,42 +6,42 @@
     # Test that we don't try to decompress a HEAD response
     http = httplib2.Http()
     response = tests.http_response_bytes(
-        headers={'content-encoding': 'gzip', 'content-length': 42},
+        headers={"content-encoding": "gzip", "content-length": 42}
     )
     with tests.server_const_bytes(response) as uri:
-        response, content = http.request(uri, 'HEAD')
+        response, content = http.request(uri, "HEAD")
         assert response.status == 200
-        assert int(response['content-length']) != 0
-        assert content == b''
+        assert int(response["content-length"]) != 0
+        assert content == b""
 
 
 def test_gzip_get():
     # Test that we support gzip compression
     http = httplib2.Http()
     response = tests.http_response_bytes(
-        headers={'content-encoding': 'gzip'},
-        body=tests.gzip_compress(b'properly compressed'),
+        headers={"content-encoding": "gzip"},
+        body=tests.gzip_compress(b"properly compressed"),
     )
     with tests.server_const_bytes(response) as uri:
-        response, content = http.request(uri, 'GET')
+        response, content = http.request(uri, "GET")
         assert response.status == 200
-        assert 'content-encoding' not in response
-        assert '-content-encoding' in response
-        assert int(response['content-length']) == len(b'properly compressed')
-        assert content == b'properly compressed'
+        assert "content-encoding" not in response
+        assert "-content-encoding" in response
+        assert int(response["content-length"]) == len(b"properly compressed")
+        assert content == b"properly compressed"
 
 
 def test_gzip_post_response():
     http = httplib2.Http()
     response = tests.http_response_bytes(
-        headers={'content-encoding': 'gzip'},
-        body=tests.gzip_compress(b'properly compressed'),
+        headers={"content-encoding": "gzip"},
+        body=tests.gzip_compress(b"properly compressed"),
     )
     with tests.server_const_bytes(response) as uri:
-        response, content = http.request(uri, 'POST', body=b'')
+        response, content = http.request(uri, "POST", body=b"")
         assert response.status == 200
-        assert 'content-encoding' not in response
-        assert '-content-encoding' in response
+        assert "content-encoding" not in response
+        assert "-content-encoding" in response
 
 
 def test_gzip_malformed_response():
@@ -49,34 +49,33 @@
     # Test that we raise a good exception when the gzip fails
     http.force_exception_to_status_code = False
     response = tests.http_response_bytes(
-        headers={'content-encoding': 'gzip'},
-        body=b'obviously not compressed',
+        headers={"content-encoding": "gzip"}, body=b"obviously not compressed"
     )
     with tests.server_const_bytes(response, request_count=2) as uri:
         with tests.assert_raises(httplib2.FailedToDecompressContent):
-            http.request(uri, 'GET')
+            http.request(uri, "GET")
 
         # Re-run the test with out the exceptions
         http.force_exception_to_status_code = True
 
-        response, content = http.request(uri, 'GET')
+        response, content = http.request(uri, "GET")
         assert response.status == 500
-        assert response.reason.startswith('Content purported')
+        assert response.reason.startswith("Content purported")
 
 
 def test_deflate_get():
     # Test that we support deflate compression
     http = httplib2.Http()
     response = tests.http_response_bytes(
-        headers={'content-encoding': 'deflate'},
-        body=tests.deflate_compress(b'properly compressed'),
+        headers={"content-encoding": "deflate"},
+        body=tests.deflate_compress(b"properly compressed"),
     )
     with tests.server_const_bytes(response) as uri:
-        response, content = http.request(uri, 'GET')
+        response, content = http.request(uri, "GET")
         assert response.status == 200
-        assert 'content-encoding' not in response
-        assert int(response['content-length']) == len(b'properly compressed')
-        assert content == b'properly compressed'
+        assert "content-encoding" not in response
+        assert int(response["content-length"]) == len(b"properly compressed")
+        assert content == b"properly compressed"
 
 
 def test_deflate_malformed_response():
@@ -84,16 +83,15 @@
     http = httplib2.Http()
     http.force_exception_to_status_code = False
     response = tests.http_response_bytes(
-        headers={'content-encoding': 'deflate'},
-        body=b'obviously not compressed',
+        headers={"content-encoding": "deflate"}, body=b"obviously not compressed"
     )
     with tests.server_const_bytes(response, request_count=2) as uri:
         with tests.assert_raises(httplib2.FailedToDecompressContent):
-            http.request(uri, 'GET')
+            http.request(uri, "GET")
 
         # Re-run the test with out the exceptions
         http.force_exception_to_status_code = True
 
-        response, content = http.request(uri, 'GET')
+        response, content = http.request(uri, "GET")
         assert response.status == 500
-        assert response.reason.startswith('Content purported')
+        assert response.reason.startswith("Content purported")