fix doc typo for library/test.rst
diff --git a/Doc/library/test.rst b/Doc/library/test.rst
index 5656b23..8dba9c9 100644
--- a/Doc/library/test.rst
+++ b/Doc/library/test.rst
@@ -447,7 +447,7 @@
    Module and package deprecation messages are suppressed during this import
    if *deprecated* is ``True``.
 
-   This function will raise :exc:`unittest.SkipTest` is the named module
+   This function will raise :exc:`unittest.SkipTest` if the named module
    cannot be imported.
 
    Example use::