diff --git a/test/functional/abc-p2p-fullblocktest.py b/test/functional/abc-p2p-fullblocktest.py
--- a/test/functional/abc-p2p-fullblocktest.py
+++ b/test/functional/abc-p2p-fullblocktest.py
@@ -163,6 +163,7 @@
 
             # Now that we added a bunch of transaction, we need to recompute
             # the merkle root.
+            make_conform_to_ctor(block)
             block.hashMerkleRoot = block.calc_merkle_root()
 
         # Check that the block size is what's expected
@@ -211,6 +212,7 @@
             block = self.blocks[block_number]
             self.add_transactions_to_block(block, new_transactions)
             old_sha256 = block.sha256
+            make_conform_to_ctor(block)
             block.hashMerkleRoot = block.calc_merkle_root()
             block.solve()
             # Update the internal state just like in next_block
diff --git a/test/functional/test_framework/blocktools.py b/test/functional/test_framework/blocktools.py
--- a/test/functional/test_framework/blocktools.py
+++ b/test/functional/test_framework/blocktools.py
@@ -28,6 +28,14 @@
     return block
 
 
+def make_conform_to_ctor(block):
+    for tx in block.vtx:
+        pad_tx(tx)
+        tx.rehash()
+    block.vtx = [block.vtx[0]] + \
+        sorted(block.vtx[1:], key=lambda tx: tx.get_id())
+
+
 def serialize_script_num(value):
     r = bytearray(0)
     if value == 0: