Fix several ResourceWarnings in test_requests.py

tests/test_requests.py

@@ -875,10 +875,11 @@ def test_form_encoded_post_query_multivalued_element(self, httpbin):
         assert prep.body == 'test=foo&test=baz'
 
     def test_different_encodings_dont_break_post(self, httpbin):
-        r = requests.post(httpbin('post'),
-            data={'stuff': json.dumps({'a': 123})},
-            params={'blah': 'asdf1234'},
-            files={'file': ('test_requests.py', open(__file__, 'rb'))})
+        with open(__file__, 'rb') as f:
+            r = requests.post(httpbin('post'),
+                data={'stuff': json.dumps({'a': 123})},
+                params={'blah': 'asdf1234'},
+                files={'file': ('test_requests.py', f)})
         assert r.status_code == 200
 
     @pytest.mark.parametrize(
@@ -889,37 +890,39 @@ def test_different_encodings_dont_break_post(self, httpbin):
             {'stuff': 'elixr'.encode('utf-8')},
         ))
     def test_unicode_multipart_post(self, httpbin, data):
-        r = requests.post(httpbin('post'),
-            data=data,
-            files={'file': ('test_requests.py', open(__file__, 'rb'))})
+        with open(__file__, 'rb') as f:
+            r = requests.post(httpbin('post'),
+                data=data,
+                files={'file': ('test_requests.py', f)})
         assert r.status_code == 200
 
     def test_unicode_multipart_post_fieldnames(self, httpbin):
         filename = os.path.splitext(__file__)[0] + '.py'
-        r = requests.Request(
-            method='POST', url=httpbin('post'),
-            data={'stuff'.encode('utf-8'): 'elixr'},
-            files={'file': ('test_requests.py', open(filename, 'rb'))})
-        prep = r.prepare()
+        with open(filename, 'rb') as f:
+            r = requests.Request(
+                method='POST', url=httpbin('post'),
+                data={'stuff'.encode('utf-8'): 'elixr'},
+                files={'file': ('test_requests.py', f)})
+            prep = r.prepare()
         assert b'name="stuff"' in prep.body
         assert b'name="b\'stuff\'"' not in prep.body
 
     def test_unicode_method_name(self, httpbin):
-        files = {'file': open(__file__, 'rb')}
-        r = requests.request(
-            method=u('POST'), url=httpbin('post'), files=files)
+        with open(__file__, 'rb') as f:
+            r = requests.request(
+                method=u('POST'), url=httpbin('post'), files={'file': f})
         assert r.status_code == 200
 
     def test_unicode_method_name_with_request_object(self, httpbin):
-        files = {'file': open(__file__, 'rb')}
-        s = requests.Session()
-        req = requests.Request(u('POST'), httpbin('post'), files=files)
-        prep = s.prepare_request(req)
-        assert isinstance(prep.method, builtin_str)
-        assert prep.method == 'POST'
+        with open(__file__, 'rb') as f:
+            s = requests.Session()
+            req = requests.Request(u('POST'), httpbin('post'), files={'file': f})
+            prep = s.prepare_request(req)
+            assert isinstance(prep.method, builtin_str)
+            assert prep.method == 'POST'
 
-        resp = s.send(prep)
-        assert resp.status_code == 200
+            resp = s.send(prep)
+            assert resp.status_code == 200
 
     def test_non_prepared_request_error(self):
         s = requests.Session()
@@ -930,13 +933,13 @@ def test_non_prepared_request_error(self):
         assert str(e.value) == 'You can only send PreparedRequests.'
 
     def test_custom_content_type(self, httpbin):
-        r = requests.post(
-            httpbin('post'),
-            data={'stuff': json.dumps({'a': 123})},
-            files={
-                'file1': ('test_requests.py', open(__file__, 'rb')),
-                'file2': ('test_requests', open(__file__, 'rb'),
-                    'text/py-content-type')})
+        with open(__file__, 'rb') as f1, open(__file__, 'rb') as f2:
+            r = requests.post(
+                httpbin('post'),
+                data={'stuff': json.dumps({'a': 123})},
+                files={
+                    'file1': ('test_requests.py', f1),
+                    'file2': ('test_requests', f2, 'text/py-content-type')})
         assert r.status_code == 200
         assert b"text/py-content-type" in r.request.body
 
@@ -1294,20 +1297,20 @@ def test_prepared_request_is_pickleable(self, httpbin):
         assert resp.status_code == 200
 
     def test_prepared_request_with_file_is_pickleable(self, httpbin):
-        files = {'file': open(__file__, 'rb')}
-        r = requests.Request('POST', httpbin('post'), files=files)
-        p = r.prepare()
+        with open(__file__, 'rb') as f:
+            r = requests.Request('POST', httpbin('post'), files={'file': f})
+            p = r.prepare()
 
-        # Verify PreparedRequest can be pickled and unpickled
-        r = pickle.loads(pickle.dumps(p))
-        assert r.url == p.url
-        assert r.headers == p.headers
-        assert r.body == p.body
+            # Verify PreparedRequest can be pickled and unpickled
+            r = pickle.loads(pickle.dumps(p))
+            assert r.url == p.url
+            assert r.headers == p.headers
+            assert r.body == p.body
 
-        # Verify unpickled PreparedRequest sends properly
-        s = requests.Session()
-        resp = s.send(r)
-        assert resp.status_code == 200
+            # Verify unpickled PreparedRequest sends properly
+            s = requests.Session()
+            resp = s.send(r)
+            assert resp.status_code == 200
 
     def test_prepared_request_with_hook_is_pickleable(self, httpbin):
         r = requests.Request('GET', httpbin('get'), hooks=default_hooks())