1 files changed, 52 insertions, 0 deletions
diff --git a/test/functional/feature_presegwit_node_upgrade.py b/test/functional/feature_presegwit_node_upgrade.py
new file mode 100755
index 0000000000..0428588da3
--- /dev/null
+++ b/test/functional/feature_presegwit_node_upgrade.py
@@ -0,0 +1,52 @@
+#!/usr/bin/env python3
+# Copyright (c) 2017-2020 The Bitcoin Core developers
+# Distributed under the MIT software license, see the accompanying
+# file COPYING or http://www.opensource.org/licenses/mit-license.php.
+"""Test a pre-segwit node upgrading to segwit consensus"""
+
+from test_framework.test_framework import BitcoinTestFramework
+from test_framework.util import (
+    assert_equal,
+    softfork_active,
+)
+
+class SegwitUpgradeTest(BitcoinTestFramework):
+    def set_test_params(self):
+        self.setup_clean_chain = True
+        self.num_nodes = 1
+        self.extra_args = [["-segwitheight=10"]]
+
+    def run_test(self):
+        """A pre-segwit node with insufficiently validated blocks needs to redownload blocks"""
+
+        self.log.info("Testing upgrade behaviour for pre-segwit node to segwit rules")
+        node = self.nodes[0]
+
+        # Node hasn't been used or connected yet
+        assert_equal(node.getblockcount(), 0)
+
+        assert not softfork_active(node, "segwit")
+
+        # Generate 8 blocks without witness data
+        node.generate(8)
+        assert_equal(node.getblockcount(), 8)
+
+        self.stop_node(0)
+        # Restarting the node (with segwit activation height set to 5) should result in a shutdown
+        # because the blockchain consists of 3 insufficiently validated blocks per segwit consensus rules.
+        node.assert_start_raises_init_error(
+                extra_args=["-segwitheight=5"],
+                expected_msg=": Witness data for blocks after height 5 requires validation. Please restart with -reindex..\nPlease restart with -reindex or -reindex-chainstate to recover.")
+
+        # As directed, the user restarts the node with -reindex
+        self.start_node(0, extra_args=["-reindex", "-segwitheight=5"])
+
+        # With the segwit consensus rules, the node is able to validate only up to block 4
+        assert_equal(node.getblockcount(), 4)
+
+        # The upgraded node should now have segwit activated
+        assert softfork_active(node, "segwit")
+
+
+if __name__ == '__main__':
+    SegwitUpgradeTest().main()