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diff --git a/src/third_party/wiredtiger/test/suite/test_hs20.py b/src/third_party/wiredtiger/test/suite/test_hs20.py
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+#!/usr/bin/env python
+#
+# Public Domain 2014-2020 MongoDB, Inc.
+# Public Domain 2008-2014 WiredTiger, Inc.
+#
+# This is free and unencumbered software released into the public domain.
+#
+# Anyone is free to copy, modify, publish, use, compile, sell, or
+# distribute this software, either in source code form or as a compiled
+# binary, for any purpose, commercial or non-commercial, and by any
+# means.
+#
+# In jurisdictions that recognize copyright laws, the author or authors
+# of this software dedicate any and all copyright interest in the
+# software to the public domain. We make this dedication for the benefit
+# of the public at large and to the detriment of our heirs and
+# successors. We intend this dedication to be an overt act of
+# relinquishment in perpetuity of all present and future rights to this
+# software under copyright law.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+# IN NO EVENT SHALL THE AUTHORS BE LIABLE FOR ANY CLAIM, DAMAGES OR
+# OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
+# ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+# OTHER DEALINGS IN THE SOFTWARE.
+
+import time, wiredtiger, wttest
+
+# test_hs20.py
+# Ensure we never reconstruct a reverse modify update in the history store based on the onpage overflow value
+def timestamp_str(t):
+    return '%x' % t
+
+class test_hs20(wttest.WiredTigerTestCase):
+    conn_config = 'cache_size=50MB,eviction=(threads_max=1)'
+    session_config = 'isolation=snapshot'
+
+    def test_hs20(self):
+        uri = 'table:test_hs20'
+        # Set a very small maximum leaf value to trigger writing overflow values
+        self.session.create(uri, 'key_format=S,value_format=S,leaf_value_max=10B')
+        cursor = self.session.open_cursor(uri)
+        self.conn.set_timestamp(
+            'oldest_timestamp=' + timestamp_str(1) + ',stable_timestamp=' + timestamp_str(1))
+
+        value1 = 'a' * 500
+        value2 = 'b' * 50
+
+        # Insert a value that is larger than the maximum leaf value.
+        for i in range(0, 10):
+            self.session.begin_transaction()
+            cursor[str(i)] = value1
+            self.session.commit_transaction('commit_timestamp=' + timestamp_str(2))
+
+        # Do 2 modifies.
+        for i in range(0, 10):
+            self.session.begin_transaction()
+            cursor.set_key(str(i))
+            mods = [wiredtiger.Modify('B', 500, 1)]
+            self.assertEqual(cursor.modify(mods), 0)
+            self.session.commit_transaction('commit_timestamp=' + timestamp_str(3))
+
+        for i in range(0, 10):
+            self.session.begin_transaction()
+            cursor.set_key(str(i))
+            mods = [wiredtiger.Modify('C', 501, 1)]
+            self.assertEqual(cursor.modify(mods), 0)
+            self.session.commit_transaction('commit_timestamp=' + timestamp_str(4))
+
+        # Insert more data to trigger eviction.
+        for i in range(10, 100000):
+            self.session.begin_transaction()
+            cursor[str(i)] = value2
+            self.session.commit_transaction('commit_timestamp=' + timestamp_str(5))
+
+        # Update the overflow values.
+        for i in range(0, 10):
+            self.session.begin_transaction()
+            cursor[str(i)] = value2
+            self.session.commit_transaction('commit_timestamp=' + timestamp_str(5))
+
+        # Do a checkpoint to move the overflow values to the history store but keep the current in memory disk image.
+        self.session.checkpoint()
+
+        # Search the first modifies.
+        for i in range(0, 10):
+            self.session.begin_transaction('read_timestamp=' + timestamp_str(3))
+            self.assertEqual(cursor[str(i)], value1 + "B")
+            self.session.rollback_transaction()