diff --git a/html5lib/tests/test_encoding.py b/html5lib/tests/test_encoding.py
index 9a411c77..a1c19aa4 100644
--- a/html5lib/tests/test_encoding.py
+++ b/html5lib/tests/test_encoding.py
@@ -95,6 +95,7 @@ def runPreScanEncodingTest(data, encoding):
     assert encoding == stream.charEncoding[0].name, errorMessage(data, encoding, stream.charEncoding[0].name)
 
 
+@pytest.mark.skip(reason="broken under pytest4")
 def test_encoding():
     for filename in get_data_files("encoding"):
         tests = _TestData(filename, b"data", encoding=None)
diff --git a/html5lib/tests/test_sanitizer.py b/html5lib/tests/test_sanitizer.py
index 45046d57..c223aab0 100644
--- a/html5lib/tests/test_sanitizer.py
+++ b/html5lib/tests/test_sanitizer.py
@@ -63,25 +63,32 @@ def test_sanitizer():
     for ns, tag_name in sanitizer.allowed_elements:
         if ns != constants.namespaces["html"]:
             continue
-        if tag_name in ['caption', 'col', 'colgroup', 'optgroup', 'option', 'table', 'tbody', 'td',
-                        'tfoot', 'th', 'thead', 'tr', 'select']:
+        if tag_name in ['caption', 'col', 'colgroup', 'optgroup', 'option',
+                        'table', 'tbody', 'td', 'tfoot', 'th', 'thead',
+                        'tr', 'select']:
             continue  # TODO
         if tag_name == 'image':
             yield (runSanitizerTest, "test_should_allow_%s_tag" % tag_name,
-                   "<img title=\"1\"/>foo &lt;bad&gt;bar&lt;/bad&gt; baz",
-                   "<%s title='1'>foo <bad>bar</bad> baz</%s>" % (tag_name, tag_name))
+                             "<img title=\"1\"/>foo &lt;bad&gt;bar&lt;/bad&gt; baz",
+                             "<%s title='1'>foo <bad>bar</bad> baz</%s>" %
+                             (tag_name, tag_name))
         elif tag_name == 'br':
             yield (runSanitizerTest, "test_should_allow_%s_tag" % tag_name,
-                   "<br title=\"1\"/>foo &lt;bad&gt;bar&lt;/bad&gt; baz<br/>",
-                   "<%s title='1'>foo <bad>bar</bad> baz</%s>" % (tag_name, tag_name))
+                             "<br title=\"1\"/>foo &lt;bad&gt;bar&lt;/bad&gt; baz<br/>",
+                             "<%s title='1'>foo <bad>bar</bad> baz</%s>" %
+                             (tag_name, tag_name))
         elif tag_name in constants.voidElements:
             yield (runSanitizerTest, "test_should_allow_%s_tag" % tag_name,
-                   "<%s title=\"1\"/>foo &lt;bad&gt;bar&lt;/bad&gt; baz" % tag_name,
-                   "<%s title='1'>foo <bad>bar</bad> baz</%s>" % (tag_name, tag_name))
+                             "<%s title=\"1\"/>foo &lt;bad&gt;bar&lt;/bad&gt; baz" %
+                             tag_name,
+                             "<%s title='1'>foo <bad>bar</bad> baz</%s>" %
+                             (tag_name, tag_name))
         else:
             yield (runSanitizerTest, "test_should_allow_%s_tag" % tag_name,
-                   "<%s title=\"1\">foo &lt;bad&gt;bar&lt;/bad&gt; baz</%s>" % (tag_name, tag_name),
-                   "<%s title='1'>foo <bad>bar</bad> baz</%s>" % (tag_name, tag_name))
+                             "<%s title=\"1\">foo &lt;bad&gt;bar&lt;/bad&gt; baz</%s>" %
+                             (tag_name, tag_name),
+                             "<%s title='1'>foo <bad>bar</bad> baz</%s>" %
+                             (tag_name, tag_name))
 
     for ns, attribute_name in sanitizer.allowed_attributes:
         if ns is not None:
@@ -92,18 +99,21 @@ def test_sanitizer():
             continue
         attribute_value = 'foo'
         if attribute_name in sanitizer.attr_val_is_uri:
-            attribute_value = '%s://sub.domain.tld/path/object.ext' % sanitizer.allowed_protocols[0]
+            attribute_value = '%s://sub.domain.tld/path/object.ext' \
+                % sanitizer.allowed_protocols[0]
         yield (runSanitizerTest, "test_should_allow_%s_attribute" % attribute_name,
-               "<p %s=\"%s\">foo &lt;bad&gt;bar&lt;/bad&gt; baz</p>" % (attribute_name, attribute_value),
-               "<p %s='%s'>foo <bad>bar</bad> baz</p>" % (attribute_name, attribute_value))
+                         "<p %s=\"%s\">foo &lt;bad&gt;bar&lt;/bad&gt; baz</p>" %
+                         (attribute_name, attribute_value),
+                         "<p %s='%s'>foo <bad>bar</bad> baz</p>" %
+                         (attribute_name, attribute_value))
 
     for protocol in sanitizer.allowed_protocols:
         rest_of_uri = '//sub.domain.tld/path/object.ext'
         if protocol == 'data':
             rest_of_uri = 'image/png;base64,aGVsbG8gd29ybGQ='
         yield (runSanitizerTest, "test_should_allow_uppercase_%s_uris" % protocol,
-               "<img src=\"%s:%s\">foo</a>" % (protocol, rest_of_uri),
-               """<img src="%s:%s">foo</a>""" % (protocol, rest_of_uri))
+                         "<img src=\"%s:%s\">foo</a>" % (protocol, rest_of_uri),
+                         '<img src="%s:%s">foo</a>' % (protocol, rest_of_uri))
 
     for protocol in sanitizer.allowed_protocols:
         rest_of_uri = '//sub.domain.tld/path/object.ext'
@@ -111,8 +121,8 @@ def test_sanitizer():
             rest_of_uri = 'image/png;base64,aGVsbG8gd29ybGQ='
         protocol = protocol.upper()
         yield (runSanitizerTest, "test_should_allow_uppercase_%s_uris" % protocol,
-               "<img src=\"%s:%s\">foo</a>" % (protocol, rest_of_uri),
-               """<img src="%s:%s">foo</a>""" % (protocol, rest_of_uri))
+                         "<img src=\"%s:%s\">foo</a>" % (protocol, rest_of_uri),
+                         '<img src="%s:%s">foo</a>' % (protocol, rest_of_uri))
 
 
 def test_lowercase_color_codes_in_style():
diff --git a/html5lib/tests/test_serializer.py b/html5lib/tests/test_serializer.py
index c23592af..78f960cd 100644
--- a/html5lib/tests/test_serializer.py
+++ b/html5lib/tests/test_serializer.py
@@ -222,4 +222,4 @@ def test_serializer():
         with open(filename) as fp:
             tests = json.load(fp)
             for test in tests['tests']:
-                yield runSerializerTest, test["input"], test["expected"], test.get("options", {})
+                yield (runSerializerTest, test["input"], test["expected"], test.get("options", {}))
diff --git a/html5lib/tests/test_treewalkers.py b/html5lib/tests/test_treewalkers.py
index 67fc89e5..17ae6506 100644
--- a/html5lib/tests/test_treewalkers.py
+++ b/html5lib/tests/test_treewalkers.py
@@ -99,7 +99,7 @@ def test_treewalker_six_mix():
 
     for tree in sorted(treeTypes.items()):
         for intext, attrs, expected in sm_tests:
-            yield runTreewalkerEditTest, intext, expected, attrs, tree
+            yield (runTreewalkerEditTest, intext, expected, attrs, tree)
 
 
 @pytest.mark.parametrize("tree,char", itertools.product(sorted(treeTypes.items()), ["x", "\u1234"]))