Issue #25523: Further a-to-an corrections.
diff --git a/Doc/library/unittest.rst b/Doc/library/unittest.rst
index 1930f78..a8d9f53 100644
--- a/Doc/library/unittest.rst
+++ b/Doc/library/unittest.rst
@@ -464,7 +464,7 @@
 .. versionadded:: 3.1
 
 Unittest supports skipping individual test methods and even whole classes of
-tests.  In addition, it supports marking a test as a "expected failure," a test
+tests.  In addition, it supports marking a test as an "expected failure," a test
 that is broken and will fail, but shouldn't be counted as a failure on a
 :class:`TestResult`.