diff --git a/doc/conf.py b/doc/conf.py
index 568b8004..e9197631 100644
--- a/doc/conf.py
+++ b/doc/conf.py
@@ -137,7 +137,7 @@
 html_theme = 'scipy'
 html_theme_path = [themedir]
 
-if 'scipyorg' in tags:
+if 'scipyorg' in tags:  # noqa: F821
     # Build for the scipy.org website
     html_theme_options = {
         "edit_link": True,
diff --git a/numpydoc/docscrape.py b/numpydoc/docscrape.py
index affbb03e..48daf0d8 100644
--- a/numpydoc/docscrape.py
+++ b/numpydoc/docscrape.py
@@ -595,7 +595,6 @@ def __str__(self):
         out = ''
 
         func, func_name = self.get_func()
-        signature = self['Signature'].replace('*', r'\*')
 
         roles = {'func': 'function',
                  'meth': 'method'}
diff --git a/numpydoc/tests/test_docscrape.py b/numpydoc/tests/test_docscrape.py
index a14f0649..4eace943 100644
--- a/numpydoc/tests/test_docscrape.py
+++ b/numpydoc/tests/test_docscrape.py
@@ -2,7 +2,6 @@
 from collections import namedtuple
 from copy import deepcopy
 import re
-import sys
 import textwrap
 import warnings
 
@@ -264,26 +263,6 @@ def test_returnyield():
     assert_raises(ValueError, NumpyDocString, doc_text)
 
 
-def test_returnyield():
-    doc_text = """
-Test having returns and yields.
-
-Returns
--------
-int
-    The number of apples.
-
-Yields
-------
-a : int
-    The number of apples.
-b : int
-    The number of bananas.
-
-"""
-    assert_raises(ValueError, NumpyDocString, doc_text)
-
-
 def test_section_twice():
     doc_text = """
 Test having a section Notes twice
@@ -859,7 +838,7 @@ class Dummy(object):
 def test_see_also_trailing_comma_warning():
     warnings.filterwarnings('error')
     with assert_warns(Warning, match='Unexpected comma or period after function list at index 43 of line .*'):
-        doc6 = NumpyDocString(
+        NumpyDocString(
             """
             z(x,theta)
 
diff --git a/numpydoc/tests/test_numpydoc.py b/numpydoc/tests/test_numpydoc.py
index e4508df2..383ca189 100644
--- a/numpydoc/tests/test_numpydoc.py
+++ b/numpydoc/tests/test_numpydoc.py
@@ -42,25 +42,28 @@ def test_mangle_docstrings():
 .. autoclass:: str
     '''
     lines = s.split('\n')
-    doc = mangle_docstrings(MockApp(), 'class', 'str', str, {}, lines)
+    mangle_docstrings(MockApp(), 'class', 'str', str, {}, lines)
     assert 'rpartition' in [x.strip() for x in lines]
 
     lines = s.split('\n')
-    doc = mangle_docstrings(MockApp(), 'class', 'str', str, {'members': ['upper']}, lines)
+    mangle_docstrings(
+        MockApp(), 'class', 'str', str, {'members': ['upper']}, lines)
     assert 'rpartition' not in [x.strip() for x in lines]
     assert 'upper' in [x.strip() for x in lines]
 
     lines = s.split('\n')
-    doc = mangle_docstrings(MockApp(), 'class', 'str', str, {'exclude-members': ALL}, lines)
+    mangle_docstrings(
+        MockApp(), 'class', 'str', str, {'exclude-members': ALL}, lines)
     assert 'rpartition' not in [x.strip() for x in lines]
     assert 'upper' not in [x.strip() for x in lines]
 
     lines = s.split('\n')
-    doc = mangle_docstrings(MockApp(), 'class', 'str', str,
-                            {'exclude-members': ['upper']}, lines)
+    mangle_docstrings(
+        MockApp(), 'class', 'str', str, {'exclude-members': ['upper']}, lines)
     assert 'rpartition' in [x.strip() for x in lines]
     assert 'upper' not in [x.strip() for x in lines]
 
 
 if __name__ == "__main__":
     import pytest
+    pytest.main()