diff --git a/Lib/test/re_tests.py b/Lib/test/re_tests.py
index 9143938..9447dd2 100755
--- a/Lib/test/re_tests.py
+++ b/Lib/test/re_tests.py
@@ -105,6 +105,19 @@
     ('\\by\\b', 'xy', FAIL),
     ('\\by\\b', 'yz', FAIL),
     ('\\by\\b', 'xyz', FAIL),
+    ('x\\b', 'xyz', FAIL),
+    ('x\\B', 'xyz', SUCCEED, '"-"', '-'),
+    ('\\Bz', 'xyz', SUCCEED, '"-"', '-'),
+    ('z\\B', 'xyz', FAIL),
+    ('\\Bx', 'xyz', FAIL),
+    ('\\Ba\\B', 'a-', FAIL, '"-"', '-'),
+    ('\\Ba\\B', '-a', FAIL, '"-"', '-'),
+    ('\\Ba\\B', '-a-', FAIL, '"-"', '-'),
+    ('\\By\\B', 'xy', FAIL),
+    ('\\By\\B', 'yz', FAIL),
+    ('\\By\\b', 'xy', SUCCEED, '"-"', '-'),
+    ('\\by\\B', 'yz', SUCCEED, '"-"', '-'),
+    ('\\By\\B', 'xyz', SUCCEED, '"-"', '-'),
     ('ab|cd', 'abc', SUCCEED, 'found', 'ab'),
     ('ab|cd', 'abcd', SUCCEED, 'found', 'ab'),
     ('()ef', 'def', SUCCEED, 'found+"-"+g1', 'ef-'),