diff --git a/qa/rpc-tests/bip65-cltv.py b/qa/rpc-tests/bip65-cltv.py
index c9d02a98f3..7f13bb9952 100755
--- a/qa/rpc-tests/bip65-cltv.py
+++ b/qa/rpc-tests/bip65-cltv.py
@@ -69,12 +69,8 @@ class BIP65Test(BitcoinTestFramework):
         if (self.nodes[0].getblockcount() != cnt + 1051):
             raise AssertionError("Failed to mine a version=4 block")
 
-        # Mine 1 old-version blocks
-        try:
-            self.nodes[1].generate(1)
-            raise AssertionError("Succeeded to mine a version=3 block after 950 version=4 blocks")
-        except JSONRPCException:
-            pass
+        # Mine 1 old-version blocks. This should fail
+        assert_raises_jsonrpc(-1,"CreateNewBlock: TestBlockValidity failed: bad-version(0x00000003)", self.nodes[1].generate, 1)
         self.sync_all()
         if (self.nodes[0].getblockcount() != cnt + 1051):
             raise AssertionError("Accepted a version=3 block after 950 version=4 blocks")
diff --git a/qa/rpc-tests/bip68-sequence.py b/qa/rpc-tests/bip68-sequence.py
index ffd461ccb0..3ed6ebe044 100755
--- a/qa/rpc-tests/bip68-sequence.py
+++ b/qa/rpc-tests/bip68-sequence.py
@@ -90,12 +90,7 @@ class BIP68Test(BitcoinTestFramework):
         tx2.vout = [CTxOut(int(value-self.relayfee*COIN), CScript([b'a']))]
         tx2.rehash()
 
-        try:
-            self.nodes[0].sendrawtransaction(ToHex(tx2))
-        except JSONRPCException as exp:
-            assert_equal(exp.error["message"], NOT_FINAL_ERROR)
-        else:
-            assert(False)
+        assert_raises_jsonrpc(-26, NOT_FINAL_ERROR, self.nodes[0].sendrawtransaction, ToHex(tx2))
 
         # Setting the version back down to 1 should disable the sequence lock,
         # so this should be accepted.
@@ -190,14 +185,12 @@ class BIP68Test(BitcoinTestFramework):
             tx.vout.append(CTxOut(int(value-self.relayfee*tx_size*COIN/1000), CScript([b'a'])))
             rawtx = self.nodes[0].signrawtransaction(ToHex(tx))["hex"]
 
-            try:
-                self.nodes[0].sendrawtransaction(rawtx)
-            except JSONRPCException as exp:
-                assert(not should_pass and using_sequence_locks)
-                assert_equal(exp.error["message"], NOT_FINAL_ERROR)
+            if (using_sequence_locks and not should_pass):
+                # This transaction should be rejected
+                assert_raises_jsonrpc(-26, NOT_FINAL_ERROR, self.nodes[0].sendrawtransaction, rawtx)
             else:
-                assert(should_pass or not using_sequence_locks)
-                # Recalculate utxos if we successfully sent the transaction
+                # This raw transaction should be accepted
+                self.nodes[0].sendrawtransaction(rawtx)
                 utxos = self.nodes[0].listunspent()
 
     # Test that sequence locks on unconfirmed inputs must have nSequence
@@ -239,14 +232,13 @@ class BIP68Test(BitcoinTestFramework):
             tx.vout = [CTxOut(int(orig_tx.vout[0].nValue - relayfee*COIN), CScript([b'a']))]
             tx.rehash()
 
-            try:
-                node.sendrawtransaction(ToHex(tx))
-            except JSONRPCException as exp:
-                assert_equal(exp.error["message"], NOT_FINAL_ERROR)
-                assert(orig_tx.hash in node.getrawmempool())
+            if (orig_tx.hash in node.getrawmempool()):
+                # sendrawtransaction should fail if the tx is in the mempool
+                assert_raises_jsonrpc(-26, NOT_FINAL_ERROR, node.sendrawtransaction, ToHex(tx))
             else:
-                # orig_tx must not be in mempool
-                assert(orig_tx.hash not in node.getrawmempool())
+                # sendrawtransaction should succeed if the tx is not in the mempool
+                node.sendrawtransaction(ToHex(tx))
+
             return tx
 
         test_nonzero_locks(tx2, self.nodes[0], self.relayfee, use_height_lock=True)
@@ -295,12 +287,7 @@ class BIP68Test(BitcoinTestFramework):
         tx5.vout[0].nValue += int(utxos[0]["amount"]*COIN)
         raw_tx5 = self.nodes[0].signrawtransaction(ToHex(tx5))["hex"]
 
-        try:
-            self.nodes[0].sendrawtransaction(raw_tx5)
-        except JSONRPCException as exp:
-            assert_equal(exp.error["message"], NOT_FINAL_ERROR)
-        else:
-            assert(False)
+        assert_raises_jsonrpc(-26, NOT_FINAL_ERROR, self.nodes[0].sendrawtransaction, raw_tx5)
 
         # Test mempool-BIP68 consistency after reorg
         #
@@ -373,12 +360,7 @@ class BIP68Test(BitcoinTestFramework):
         tx3.vout = [CTxOut(int(tx2.vout[0].nValue - self.relayfee*COIN), CScript([b'a']))]
         tx3.rehash()
 
-        try:
-            self.nodes[0].sendrawtransaction(ToHex(tx3))
-        except JSONRPCException as exp:
-            assert_equal(exp.error["message"], NOT_FINAL_ERROR)
-        else:
-            assert(False)
+        assert_raises_jsonrpc(-26, NOT_FINAL_ERROR, self.nodes[0].sendrawtransaction, ToHex(tx3))
 
         # make a block that violates bip68; ensure that the tip updates
         tip = int(self.nodes[0].getbestblockhash(), 16)
diff --git a/qa/rpc-tests/bipdersig.py b/qa/rpc-tests/bipdersig.py
index fa54bc2749..371cc41bb7 100755
--- a/qa/rpc-tests/bipdersig.py
+++ b/qa/rpc-tests/bipdersig.py
@@ -68,12 +68,8 @@ class BIP66Test(BitcoinTestFramework):
         if (self.nodes[0].getblockcount() != cnt + 1051):
             raise AssertionError("Failed to mine a version=3 block")
 
-        # Mine 1 old-version blocks
-        try:
-            self.nodes[1].generate(1)
-            raise AssertionError("Succeeded to mine a version=2 block after 950 version=3 blocks")
-        except JSONRPCException:
-            pass
+        # Mine 1 old-version blocks. This should fail
+        assert_raises_jsonrpc(-1, "CreateNewBlock: TestBlockValidity failed: bad-version(0x00000002)", self.nodes[1].generate, 1)
         self.sync_all()
         if (self.nodes[0].getblockcount() != cnt + 1051):
             raise AssertionError("Accepted a version=2 block after 950 version=3 blocks")
diff --git a/qa/rpc-tests/blockchain.py b/qa/rpc-tests/blockchain.py
index 67b5826840..596aed50ec 100755
--- a/qa/rpc-tests/blockchain.py
+++ b/qa/rpc-tests/blockchain.py
@@ -14,10 +14,9 @@ Tests correspond to code in rpc/blockchain.cpp.
 from decimal import Decimal
 
 from test_framework.test_framework import BitcoinTestFramework
-from test_framework.authproxy import JSONRPCException
 from test_framework.util import (
     assert_equal,
-    assert_raises,
+    assert_raises_jsonrpc,
     assert_is_hex_string,
     assert_is_hash_string,
     start_nodes,
@@ -58,8 +57,7 @@ class BlockchainTest(BitcoinTestFramework):
     def _test_getblockheader(self):
         node = self.nodes[0]
 
-        assert_raises(
-            JSONRPCException, lambda: node.getblockheader('nonsense'))
+        assert_raises_jsonrpc(-5, "Block not found", node.getblockheader, "nonsense")
 
         besthash = node.getbestblockhash()
         secondbesthash = node.getblockhash(199)
diff --git a/qa/rpc-tests/disablewallet.py b/qa/rpc-tests/disablewallet.py
index ff7121659b..2f729e19bf 100755
--- a/qa/rpc-tests/disablewallet.py
+++ b/qa/rpc-tests/disablewallet.py
@@ -30,19 +30,10 @@ class DisableWalletTest (BitcoinTestFramework):
         x = self.nodes[0].validateaddress('mneYUmWYsuk7kySiURxCi3AGxrAqZxLgPZ')
         assert(x['isvalid'] == True)
 
-        # Checking mining to an address without a wallet
-        try:
-            self.nodes[0].generatetoaddress(1, 'mneYUmWYsuk7kySiURxCi3AGxrAqZxLgPZ')
-        except JSONRPCException as e:
-            assert("Invalid address" not in e.error['message'])
-            assert("ProcessNewBlock, block not accepted" not in e.error['message'])
-            assert("Couldn't create new block" not in e.error['message'])
-
-        try:
-            self.nodes[0].generatetoaddress(1, '3J98t1WpEZ73CNmQviecrnyiWrnqRhWNLy')
-            raise AssertionError("Must not mine to invalid address!")
-        except JSONRPCException as e:
-            assert("Invalid address" in e.error['message'])
+        # Checking mining to an address without a wallet. Generating to a valid address should succeed
+        # but generating to an invalid address will fail.
+        self.nodes[0].generatetoaddress(1, 'mneYUmWYsuk7kySiURxCi3AGxrAqZxLgPZ')
+        assert_raises_jsonrpc(-5, "Invalid address", self.nodes[0].generatetoaddress, 1, '3J98t1WpEZ73CNmQviecrnyiWrnqRhWNLy')
 
 if __name__ == '__main__':
     DisableWalletTest ().main ()
diff --git a/qa/rpc-tests/getblocktemplate_proposals.py b/qa/rpc-tests/getblocktemplate_proposals.py
index 3b17dfcfb5..67745f77d1 100755
--- a/qa/rpc-tests/getblocktemplate_proposals.py
+++ b/qa/rpc-tests/getblocktemplate_proposals.py
@@ -105,7 +105,7 @@ class GetBlockTemplateProposalTest(BitcoinTestFramework):
 
         # Test 3: Truncated final tx
         lastbyte = txlist[-1].pop()
-        assert_raises(JSONRPCException, assert_template, node, tmpl, txlist, 'n/a')
+        assert_raises_jsonrpc(-22, "Block decode failed", assert_template, node, tmpl, txlist, 'n/a')
         txlist[-1].append(lastbyte)
 
         # Test 4: Add an invalid tx to the end (duplicate of gen tx)
@@ -126,7 +126,7 @@ class GetBlockTemplateProposalTest(BitcoinTestFramework):
 
         # Test 7: Bad tx count
         txlist.append(b'')
-        assert_raises(JSONRPCException, assert_template, node, tmpl, txlist, 'n/a')
+        assert_raises_jsonrpc(-22, 'Block decode failed', assert_template, node, tmpl, txlist, 'n/a')
         txlist.pop()
 
         # Test 8: Bad bits
diff --git a/qa/rpc-tests/keypool.py b/qa/rpc-tests/keypool.py
index 4b9936a1fd..cee58563f0 100755
--- a/qa/rpc-tests/keypool.py
+++ b/qa/rpc-tests/keypool.py
@@ -28,11 +28,7 @@ class KeyPoolTest(BitcoinTestFramework):
         assert(addr_before_encrypting_data['hdmasterkeyid'] != wallet_info['hdmasterkeyid'])
         assert(addr_data['hdmasterkeyid'] == wallet_info['hdmasterkeyid'])
         
-        try:
-            addr = nodes[0].getnewaddress()
-            raise AssertionError('Keypool should be exhausted after one address')
-        except JSONRPCException as e:
-            assert(e.error['code']==-12)
+        assert_raises_jsonrpc(-12, "Error: Keypool ran out, please call keypoolrefill first", nodes[0].getnewaddress)
 
         # put three new keys in the keypool
         nodes[0].walletpassphrase('test', 12000)
@@ -48,11 +44,7 @@ class KeyPoolTest(BitcoinTestFramework):
         # assert that four unique addresses were returned
         assert(len(addr) == 4)
         # the next one should fail
-        try:
-            addr = nodes[0].getrawchangeaddress()
-            raise AssertionError('Keypool should be exhausted after three addresses')
-        except JSONRPCException as e:
-            assert(e.error['code']==-12)
+        assert_raises_jsonrpc(-12, "Keypool ran out", nodes[0].getrawchangeaddress)
 
         # refill keypool with three new addresses
         nodes[0].walletpassphrase('test', 1)
@@ -66,11 +58,7 @@ class KeyPoolTest(BitcoinTestFramework):
         nodes[0].generate(1)
         nodes[0].generate(1)
         nodes[0].generate(1)
-        try:
-            nodes[0].generate(1)
-            raise AssertionError('Keypool should be exhausted after three addesses')
-        except JSONRPCException as e:
-            assert(e.error['code']==-12)
+        assert_raises_jsonrpc(-12, "Keypool ran out", nodes[0].generate, 1)
 
     def __init__(self):
         super().__init__()
diff --git a/qa/rpc-tests/mempool_packages.py b/qa/rpc-tests/mempool_packages.py
index 915d174052..17e3a9a967 100755
--- a/qa/rpc-tests/mempool_packages.py
+++ b/qa/rpc-tests/mempool_packages.py
@@ -112,10 +112,7 @@ class MempoolPackagesTest(BitcoinTestFramework):
             assert_equal(mempool[x]['descendantfees'], descendant_fees * COIN + 1000)
 
         # Adding one more transaction on to the chain should fail.
-        try:
-            self.chain_transaction(self.nodes[0], txid, vout, value, fee, 1)
-        except JSONRPCException as e:
-            self.log.info("too-long-ancestor-chain successfully rejected")
+        assert_raises_jsonrpc(-26, "too-long-mempool-chain", self.chain_transaction, self.nodes[0], txid, vout, value, fee, 1)
 
         # Check that prioritising a tx before it's added to the mempool works
         # First clear the mempool by mining a block.
@@ -155,19 +152,19 @@ class MempoolPackagesTest(BitcoinTestFramework):
         for i in range(10):
             transaction_package.append({'txid': txid, 'vout': i, 'amount': sent_value})
 
-        for i in range(MAX_DESCENDANTS):
+        # Sign and send up to MAX_DESCENDANT transactions chained off the parent tx
+        for i in range(MAX_DESCENDANTS - 1):
             utxo = transaction_package.pop(0)
-            try:
-                (txid, sent_value) = self.chain_transaction(self.nodes[0], utxo['txid'], utxo['vout'], utxo['amount'], fee, 10)
-                for j in range(10):
-                    transaction_package.append({'txid': txid, 'vout': j, 'amount': sent_value})
-                if i == MAX_DESCENDANTS - 2:
-                    mempool = self.nodes[0].getrawmempool(True)
-                    assert_equal(mempool[parent_transaction]['descendantcount'], MAX_DESCENDANTS)
-            except JSONRPCException as e:
-                self.log.info(e.error['message'])
-                assert_equal(i, MAX_DESCENDANTS - 1)
-                self.log.info("tx that would create too large descendant package successfully rejected")
+            (txid, sent_value) = self.chain_transaction(self.nodes[0], utxo['txid'], utxo['vout'], utxo['amount'], fee, 10)
+            for j in range(10):
+                transaction_package.append({'txid': txid, 'vout': j, 'amount': sent_value})
+
+        mempool = self.nodes[0].getrawmempool(True)
+        assert_equal(mempool[parent_transaction]['descendantcount'], MAX_DESCENDANTS)
+
+        # Sending one more chained transaction will fail
+        utxo = transaction_package.pop(0)
+        assert_raises_jsonrpc(-26, "too-long-mempool-chain", self.chain_transaction, self.nodes[0], utxo['txid'], utxo['vout'], utxo['amount'], fee, 10)
 
         # TODO: check that node1's mempool is as expected
 
diff --git a/qa/rpc-tests/mempool_reorg.py b/qa/rpc-tests/mempool_reorg.py
index 585e4147b2..812b54ffcb 100755
--- a/qa/rpc-tests/mempool_reorg.py
+++ b/qa/rpc-tests/mempool_reorg.py
@@ -30,9 +30,10 @@ class MempoolCoinbaseTest(BitcoinTestFramework):
         self.sync_all()
 
     def run_test(self):
-        start_count = self.nodes[0].getblockcount()
+        # Start with a 200 block chain
+        assert_equal(self.nodes[0].getblockcount(), 200)
 
-        # Mine three blocks. After this, nodes[0] blocks
+        # Mine four blocks. After this, nodes[0] blocks
         # 101, 102, and 103 are spend-able.
         new_blocks = self.nodes[1].generate(4)
         self.sync_all()
@@ -52,19 +53,21 @@ class MempoolCoinbaseTest(BitcoinTestFramework):
         spend_102_raw = create_tx(self.nodes[0], coinbase_txids[2], node0_address, 49.99)
         spend_103_raw = create_tx(self.nodes[0], coinbase_txids[3], node0_address, 49.99)
 
-        # Create a block-height-locked transaction which will be invalid after reorg
+        # Create a transaction which is time-locked to two blocks in the future
         timelock_tx = self.nodes[0].createrawtransaction([{"txid": coinbase_txids[0], "vout": 0}], {node0_address: 49.99})
         # Set the time lock
         timelock_tx = timelock_tx.replace("ffffffff", "11111191", 1)
         timelock_tx = timelock_tx[:-8] + hex(self.nodes[0].getblockcount() + 2)[2:] + "000000"
         timelock_tx = self.nodes[0].signrawtransaction(timelock_tx)["hex"]
-        assert_raises(JSONRPCException, self.nodes[0].sendrawtransaction, timelock_tx)
+        # This will raise an exception because the timelock transaction is too immature to spend
+        assert_raises_jsonrpc(-26, "non-final", self.nodes[0].sendrawtransaction, timelock_tx)
 
         # Broadcast and mine spend_102 and 103:
         spend_102_id = self.nodes[0].sendrawtransaction(spend_102_raw)
         spend_103_id = self.nodes[0].sendrawtransaction(spend_103_raw)
         self.nodes[0].generate(1)
-        assert_raises(JSONRPCException, self.nodes[0].sendrawtransaction, timelock_tx)
+        # Time-locked transaction is still too immature to spend
+        assert_raises_jsonrpc(-26,'non-final', self.nodes[0].sendrawtransaction, timelock_tx)
 
         # Create 102_1 and 103_1:
         spend_102_1_raw = create_tx(self.nodes[0], spend_102_id, node1_address, 49.98)
@@ -73,6 +76,7 @@ class MempoolCoinbaseTest(BitcoinTestFramework):
         # Broadcast and mine 103_1:
         spend_103_1_id = self.nodes[0].sendrawtransaction(spend_103_1_raw)
         last_block = self.nodes[0].generate(1)
+        # Time-locked transaction can now be spent
         timelock_tx_id = self.nodes[0].sendrawtransaction(timelock_tx)
 
         # ... now put spend_101 and spend_102_1 in memory pools:
@@ -85,6 +89,8 @@ class MempoolCoinbaseTest(BitcoinTestFramework):
 
         for node in self.nodes:
             node.invalidateblock(last_block[0])
+        # Time-locked transaction is now too immature and has been removed from the mempool
+        # spend_103_1 has been re-orged out of the chain and is back in the mempool
         assert_equal(set(self.nodes[0].getrawmempool()), {spend_101_id, spend_102_1_id, spend_103_1_id})
 
         # Use invalidateblock to re-org back and make all those coinbase spends
diff --git a/qa/rpc-tests/mempool_spendcoinbase.py b/qa/rpc-tests/mempool_spendcoinbase.py
index 4818ad8bda..f562a93d86 100755
--- a/qa/rpc-tests/mempool_spendcoinbase.py
+++ b/qa/rpc-tests/mempool_spendcoinbase.py
@@ -45,7 +45,7 @@ class MempoolSpendCoinbaseTest(BitcoinTestFramework):
         spend_101_id = self.nodes[0].sendrawtransaction(spends_raw[0])
 
         # coinbase at height 102 should be too immature to spend
-        assert_raises(JSONRPCException, self.nodes[0].sendrawtransaction, spends_raw[1])
+        assert_raises_jsonrpc(-26,"bad-txns-premature-spend-of-coinbase", self.nodes[0].sendrawtransaction, spends_raw[1])
 
         # mempool should have just spend_101:
         assert_equal(self.nodes[0].getrawmempool(), [ spend_101_id ])
diff --git a/qa/rpc-tests/nulldummy.py b/qa/rpc-tests/nulldummy.py
index 4b215a70b0..7b19fbfd82 100755
--- a/qa/rpc-tests/nulldummy.py
+++ b/qa/rpc-tests/nulldummy.py
@@ -66,38 +66,38 @@ class NULLDUMMYTest(BitcoinTestFramework):
 
         self.log.info("Test 1: NULLDUMMY compliant base transactions should be accepted to mempool and mined before activation [430]")
         test1txs = [self.create_transaction(self.nodes[0], coinbase_txid[0], self.ms_address, 49)]
-        txid1 = self.tx_submit(self.nodes[0], test1txs[0])
+        txid1 = self.nodes[0].sendrawtransaction(bytes_to_hex_str(test1txs[0].serialize_with_witness()), True)
         test1txs.append(self.create_transaction(self.nodes[0], txid1, self.ms_address, 48))
-        txid2 = self.tx_submit(self.nodes[0], test1txs[1])
+        txid2 = self.nodes[0].sendrawtransaction(bytes_to_hex_str(test1txs[1].serialize_with_witness()), True)
         test1txs.append(self.create_transaction(self.nodes[0], coinbase_txid[1], self.wit_ms_address, 49))
-        txid3 = self.tx_submit(self.nodes[0], test1txs[2])
+        txid3 = self.nodes[0].sendrawtransaction(bytes_to_hex_str(test1txs[2].serialize_with_witness()), True)
         self.block_submit(self.nodes[0], test1txs, False, True)
 
         self.log.info("Test 2: Non-NULLDUMMY base multisig transaction should not be accepted to mempool before activation")
         test2tx = self.create_transaction(self.nodes[0], txid2, self.ms_address, 47)
         trueDummy(test2tx)
-        txid4 = self.tx_submit(self.nodes[0], test2tx, NULLDUMMY_ERROR)
+        assert_raises_jsonrpc(-26, NULLDUMMY_ERROR, self.nodes[0].sendrawtransaction, bytes_to_hex_str(test2tx.serialize_with_witness()), True)
 
         self.log.info("Test 3: Non-NULLDUMMY base transactions should be accepted in a block before activation [431]")
         self.block_submit(self.nodes[0], [test2tx], False, True)
 
-        self.log.info("Test 4: Non-NULLDUMMY base multisig transaction is invalid after activation")
-        test4tx = self.create_transaction(self.nodes[0], txid4, self.address, 46)
+        self.log.info ("Test 4: Non-NULLDUMMY base multisig transaction is invalid after activation")
+        test4tx = self.create_transaction(self.nodes[0], test2tx.hash, self.address, 46)
         test6txs=[CTransaction(test4tx)]
         trueDummy(test4tx)
-        self.tx_submit(self.nodes[0], test4tx, NULLDUMMY_ERROR)
+        assert_raises_jsonrpc(-26, NULLDUMMY_ERROR, self.nodes[0].sendrawtransaction, bytes_to_hex_str(test4tx.serialize_with_witness()), True)
         self.block_submit(self.nodes[0], [test4tx])
 
-        self.log.info("Test 5: Non-NULLDUMMY P2WSH multisig transaction invalid after activation")
+        print ("Test 5: Non-NULLDUMMY P2WSH multisig transaction invalid after activation")
         test5tx = self.create_transaction(self.nodes[0], txid3, self.wit_address, 48)
         test6txs.append(CTransaction(test5tx))
         test5tx.wit.vtxinwit[0].scriptWitness.stack[0] = b'\x01'
-        self.tx_submit(self.nodes[0], test5tx, NULLDUMMY_ERROR)
+        assert_raises_jsonrpc(-26, NULLDUMMY_ERROR, self.nodes[0].sendrawtransaction, bytes_to_hex_str(test5tx.serialize_with_witness()), True)
         self.block_submit(self.nodes[0], [test5tx], True)
 
         self.log.info("Test 6: NULLDUMMY compliant base/witness transactions should be accepted to mempool and in block after activation [432]")
         for i in test6txs:
-            self.tx_submit(self.nodes[0], i)
+            self.nodes[0].sendrawtransaction(bytes_to_hex_str(i.serialize_with_witness()), True)
         self.block_submit(self.nodes[0], test6txs, True, True)
 
 
@@ -112,17 +112,6 @@ class NULLDUMMYTest(BitcoinTestFramework):
         return tx
 
 
-    def tx_submit(self, node, tx, msg = ""):
-        tx.rehash()
-        try:
-            node.sendrawtransaction(bytes_to_hex_str(tx.serialize_with_witness()), True)
-        except JSONRPCException as exp:
-            assert_equal(exp.error["message"], msg)
-        else:
-            assert_equal('', msg)
-        return tx.hash
-
-
     def block_submit(self, node, txs, witness = False, accept = False):
         block = create_block(self.tip, create_coinbase(self.lastblockheight + 1), self.lastblocktime + 1)
         block.nVersion = 4
diff --git a/qa/rpc-tests/prioritise_transaction.py b/qa/rpc-tests/prioritise_transaction.py
index 10f596b2cb..0b04ad17ab 100755
--- a/qa/rpc-tests/prioritise_transaction.py
+++ b/qa/rpc-tests/prioritise_transaction.py
@@ -107,13 +107,9 @@ class PrioritiseTransactionTest(BitcoinTestFramework):
         tx_hex = self.nodes[0].signrawtransaction(raw_tx)["hex"]
         tx_id = self.nodes[0].decoderawtransaction(tx_hex)["txid"]
 
-        try:
-            self.nodes[0].sendrawtransaction(tx_hex)
-        except JSONRPCException as exp:
-            assert_equal(exp.error['code'], -26) # insufficient fee
-            assert(tx_id not in self.nodes[0].getrawmempool())
-        else:
-            assert(False)
+        # This will raise an exception due to min relay fee not being met
+        assert_raises_jsonrpc(-26, "66: min relay fee not met", self.nodes[0].sendrawtransaction, tx_hex)
+        assert(tx_id not in self.nodes[0].getrawmempool())
 
         # This is a less than 1000-byte transaction, so just set the fee
         # to be the minimum for a 1000 byte transaction and check that it is
diff --git a/qa/rpc-tests/replace-by-fee.py b/qa/rpc-tests/replace-by-fee.py
index 8e2abea6a5..163c304eba 100755
--- a/qa/rpc-tests/replace-by-fee.py
+++ b/qa/rpc-tests/replace-by-fee.py
@@ -125,12 +125,8 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         tx1b.vout = [CTxOut(1*COIN, CScript([b'b']))]
         tx1b_hex = txToHex(tx1b)
 
-        try:
-            tx1b_txid = self.nodes[0].sendrawtransaction(tx1b_hex, True)
-        except JSONRPCException as exp:
-            assert_equal(exp.error['code'], -26) # insufficient fee
-        else:
-            assert(False)
+        # This will raise an exception due to insufficient fee
+        assert_raises_jsonrpc(-26, "insufficient fee", self.nodes[0].sendrawtransaction, tx1b_hex, True)
 
         # Extra 0.1 BTC fee
         tx1b = CTransaction()
@@ -172,12 +168,8 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         dbl_tx.vout = [CTxOut(initial_nValue - 30*COIN, CScript([1]))]
         dbl_tx_hex = txToHex(dbl_tx)
 
-        try:
-            self.nodes[0].sendrawtransaction(dbl_tx_hex, True)
-        except JSONRPCException as exp:
-            assert_equal(exp.error['code'], -26) # insufficient fee
-        else:
-            assert(False) # transaction mistakenly accepted!
+        # This will raise an exception due to insufficient fee
+        assert_raises_jsonrpc(-26, "insufficient fee", self.nodes[0].sendrawtransaction, dbl_tx_hex, True)
 
         # Accepted with sufficient fee
         dbl_tx = CTransaction()
@@ -237,12 +229,8 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         dbl_tx.vin = [CTxIn(tx0_outpoint, nSequence=0)]
         dbl_tx.vout = [CTxOut(initial_nValue - fee*n, CScript([1]))]
         dbl_tx_hex = txToHex(dbl_tx)
-        try:
-            self.nodes[0].sendrawtransaction(dbl_tx_hex, True)
-        except JSONRPCException as exp:
-            assert_equal(exp.error['code'], -26) # insufficient fee
-        else:
-            assert(False)
+        # This will raise an exception due to insufficient fee
+        assert_raises_jsonrpc(-26, "insufficient fee", self.nodes[0].sendrawtransaction, dbl_tx_hex, True)
 
         # 1 BTC fee is enough
         dbl_tx = CTransaction()
@@ -269,13 +257,8 @@ class ReplaceByFeeTest(BitcoinTestFramework):
             dbl_tx.vin = [CTxIn(tx0_outpoint, nSequence=0)]
             dbl_tx.vout = [CTxOut(initial_nValue - 2*fee*n, CScript([1]))]
             dbl_tx_hex = txToHex(dbl_tx)
-            try:
-                self.nodes[0].sendrawtransaction(dbl_tx_hex, True)
-            except JSONRPCException as exp:
-                assert_equal(exp.error['code'], -26)
-                assert_equal("too many potential replacements" in exp.error['message'], True)
-            else:
-                assert(False)
+            # This will raise an exception
+            assert_raises_jsonrpc(-26, "too many potential replacements", self.nodes[0].sendrawtransaction, dbl_tx_hex, True)
 
             for tx in tree_txs:
                 tx.rehash()
@@ -298,12 +281,8 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         tx1b.vout = [CTxOut(int(0.001*COIN), CScript([b'a'*999000]))]
         tx1b_hex = txToHex(tx1b)
 
-        try:
-            tx1b_txid = self.nodes[0].sendrawtransaction(tx1b_hex, True)
-        except JSONRPCException as exp:
-            assert_equal(exp.error['code'], -26) # insufficient fee
-        else:
-            assert(False)
+        # This will raise an exception due to insufficient fee
+        assert_raises_jsonrpc(-26, "insufficient fee", self.nodes[0].sendrawtransaction, tx1b_hex, True)
 
     def test_spends_of_conflicting_outputs(self):
         """Replacements that spend conflicting tx outputs are rejected"""
@@ -325,12 +304,8 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         tx2.vout = tx1a.vout
         tx2_hex = txToHex(tx2)
 
-        try:
-            tx2_txid = self.nodes[0].sendrawtransaction(tx2_hex, True)
-        except JSONRPCException as exp:
-            assert_equal(exp.error['code'], -26)
-        else:
-            assert(False)
+        # This will raise an exception
+        assert_raises_jsonrpc(-26, "bad-txns-spends-conflicting-tx", self.nodes[0].sendrawtransaction, tx2_hex, True)
 
         # Spend tx1a's output to test the indirect case.
         tx1b = CTransaction()
@@ -346,12 +321,8 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         tx2.vout = tx1a.vout
         tx2_hex = txToHex(tx2)
 
-        try:
-            tx2_txid = self.nodes[0].sendrawtransaction(tx2_hex, True)
-        except JSONRPCException as exp:
-            assert_equal(exp.error['code'], -26)
-        else:
-            assert(False)
+        # This will raise an exception
+        assert_raises_jsonrpc(-26, "bad-txns-spends-conflicting-tx", self.nodes[0].sendrawtransaction, tx2_hex, True)
 
     def test_new_unconfirmed_inputs(self):
         """Replacements that add new unconfirmed inputs are rejected"""
@@ -369,12 +340,8 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         tx2.vout = tx1.vout
         tx2_hex = txToHex(tx2)
 
-        try:
-            tx2_txid = self.nodes[0].sendrawtransaction(tx2_hex, True)
-        except JSONRPCException as exp:
-            assert_equal(exp.error['code'], -26)
-        else:
-            assert(False)
+        # This will raise an exception
+        assert_raises_jsonrpc(-26, "replacement-adds-unconfirmed", self.nodes[0].sendrawtransaction, tx2_hex, True)
 
     def test_too_many_replacements(self):
         """Replacements that evict too many transactions are rejected"""
@@ -419,13 +386,8 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         double_tx.vout = [CTxOut(double_spend_value, CScript([b'a']))]
         double_tx_hex = txToHex(double_tx)
 
-        try:
-            self.nodes[0].sendrawtransaction(double_tx_hex, True)
-        except JSONRPCException as exp:
-            assert_equal(exp.error['code'], -26)
-            assert_equal("too many potential replacements" in exp.error['message'], True)
-        else:
-            assert(False)
+        # This will raise an exception
+        assert_raises_jsonrpc(-26, "too many potential replacements", self.nodes[0].sendrawtransaction, double_tx_hex, True)
 
         # If we remove an input, it should pass
         double_tx = CTransaction()
@@ -451,13 +413,8 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         tx1b.vout = [CTxOut(int(0.9*COIN), CScript([b'b']))]
         tx1b_hex = txToHex(tx1b)
 
-        try:
-            tx1b_txid = self.nodes[0].sendrawtransaction(tx1b_hex, True)
-        except JSONRPCException as exp:
-            assert_equal(exp.error['code'], -26)
-        else:
-            self.log.info(tx1b_txid)
-            assert(False)
+        # This will raise an exception
+        assert_raises_jsonrpc(-26, "txn-mempool-conflict", self.nodes[0].sendrawtransaction, tx1b_hex, True)
 
         tx1_outpoint = make_utxo(self.nodes[0], int(1.1*COIN))
 
@@ -474,12 +431,8 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         tx2b.vout = [CTxOut(int(0.9*COIN), CScript([b'b']))]
         tx2b_hex = txToHex(tx2b)
 
-        try:
-            tx2b_txid = self.nodes[0].sendrawtransaction(tx2b_hex, True)
-        except JSONRPCException as exp:
-            assert_equal(exp.error['code'], -26)
-        else:
-            assert(False)
+        # This will raise an exception
+        assert_raises_jsonrpc(-26, "txn-mempool-conflict", self.nodes[0].sendrawtransaction, tx2b_hex, True)
 
         # Now create a new transaction that spends from tx1a and tx2a
         # opt-in on one of the inputs
@@ -531,12 +484,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         tx1b_hex = txToHex(tx1b)
 
         # Verify tx1b cannot replace tx1a.
-        try:
-            tx1b_txid = self.nodes[0].sendrawtransaction(tx1b_hex, True)
-        except JSONRPCException as exp:
-            assert_equal(exp.error['code'], -26)
-        else:
-            assert(False)
+        assert_raises_jsonrpc(-26, "insufficient fee", self.nodes[0].sendrawtransaction, tx1b_hex, True)
 
         # Use prioritisetransaction to set tx1a's fee to 0.
         self.nodes[0].prioritisetransaction(tx1a_txid, int(-0.1*COIN))
@@ -563,12 +511,7 @@ class ReplaceByFeeTest(BitcoinTestFramework):
         tx2b_hex = txToHex(tx2b)
 
         # Verify tx2b cannot replace tx2a.
-        try:
-            tx2b_txid = self.nodes[0].sendrawtransaction(tx2b_hex, True)
-        except JSONRPCException as exp:
-            assert_equal(exp.error['code'], -26)
-        else:
-            assert(False)
+        assert_raises_jsonrpc(-26, "insufficient fee", self.nodes[0].sendrawtransaction, tx2b_hex, True)
 
         # Now prioritise tx2b to have a higher modified fee
         self.nodes[0].prioritisetransaction(tx2b.hash, int(0.1*COIN))
diff --git a/qa/rpc-tests/rpcbind_test.py b/qa/rpc-tests/rpcbind_test.py
index 220bf4ddd0..8720a345ce 100755
--- a/qa/rpc-tests/rpcbind_test.py
+++ b/qa/rpc-tests/rpcbind_test.py
@@ -92,11 +92,7 @@ class RPCBindTest(BitcoinTestFramework):
 
         # Check that with invalid rpcallowip, we are denied
         self.run_allowip_test([non_loopback_ip], non_loopback_ip, defaultport)
-        try:
-            self.run_allowip_test(['1.1.1.1'], non_loopback_ip, defaultport)
-            assert(not 'Connection not denied by rpcallowip as expected')
-        except JSONRPCException:
-            pass
+        assert_raises_jsonrpc(-342, "non-JSON HTTP response with '403 Forbidden' from server", self.run_allowip_test, ['1.1.1.1'], non_loopback_ip, defaultport)
 
 if __name__ == '__main__':
     RPCBindTest().main()
diff --git a/qa/rpc-tests/segwit.py b/qa/rpc-tests/segwit.py
index a6e3c29bd2..5b1fba8eec 100755
--- a/qa/rpc-tests/segwit.py
+++ b/qa/rpc-tests/segwit.py
@@ -105,22 +105,12 @@ class SegWitTest(BitcoinTestFramework):
         assert_equal(len(node.getblock(block[0])["tx"]), 1)
         sync_blocks(self.nodes)
 
-    def fail_accept(self, node, txid, sign, redeem_script=""):
-        try:
-            send_to_witness(1, node, getutxo(txid), self.pubkey[0], False, Decimal("49.998"), sign, redeem_script)
-        except JSONRPCException as exp:
-            assert(exp.error["code"] == -26)
-        else:
-            raise AssertionError("Tx should not have been accepted")
+    def fail_accept(self, node, error_msg, txid, sign, redeem_script=""):
+        assert_raises_jsonrpc(-26, error_msg, send_to_witness, 1, node, getutxo(txid), self.pubkey[0], False, Decimal("49.998"), sign, redeem_script)
 
     def fail_mine(self, node, txid, sign, redeem_script=""):
         send_to_witness(1, node, getutxo(txid), self.pubkey[0], False, Decimal("49.998"), sign, redeem_script)
-        try:
-            node.generate(1)
-        except JSONRPCException as exp:
-            assert(exp.error["code"] == -1)
-        else:
-            raise AssertionError("Created valid block when TestBlockValidity should have failed")
+        assert_raises_jsonrpc(-1, "CreateNewBlock: TestBlockValidity failed", node.generate, 1)
         sync_blocks(self.nodes)
 
     def run_test(self):
@@ -177,18 +167,18 @@ class SegWitTest(BitcoinTestFramework):
 
         self.log.info("Verify default node can't accept any witness format txs before fork")
         # unsigned, no scriptsig
-        self.fail_accept(self.nodes[0], wit_ids[NODE_0][WIT_V0][0], False)
-        self.fail_accept(self.nodes[0], wit_ids[NODE_0][WIT_V1][0], False)
-        self.fail_accept(self.nodes[0], p2sh_ids[NODE_0][WIT_V0][0], False)
-        self.fail_accept(self.nodes[0], p2sh_ids[NODE_0][WIT_V1][0], False)
+        self.fail_accept(self.nodes[0], "mandatory-script-verify-flag", wit_ids[NODE_0][WIT_V0][0], False)
+        self.fail_accept(self.nodes[0], "mandatory-script-verify-flag", wit_ids[NODE_0][WIT_V1][0], False)
+        self.fail_accept(self.nodes[0], "mandatory-script-verify-flag", p2sh_ids[NODE_0][WIT_V0][0], False)
+        self.fail_accept(self.nodes[0], "mandatory-script-verify-flag", p2sh_ids[NODE_0][WIT_V1][0], False)
         # unsigned with redeem script
-        self.fail_accept(self.nodes[0], p2sh_ids[NODE_0][WIT_V0][0], False, witness_script(False, self.pubkey[0]))
-        self.fail_accept(self.nodes[0], p2sh_ids[NODE_0][WIT_V1][0], False, witness_script(True, self.pubkey[0]))
+        self.fail_accept(self.nodes[0], "mandatory-script-verify-flag", p2sh_ids[NODE_0][WIT_V0][0], False, witness_script(False, self.pubkey[0]))
+        self.fail_accept(self.nodes[0], "mandatory-script-verify-flag", p2sh_ids[NODE_0][WIT_V1][0], False, witness_script(True, self.pubkey[0]))
         # signed
-        self.fail_accept(self.nodes[0], wit_ids[NODE_0][WIT_V0][0], True)
-        self.fail_accept(self.nodes[0], wit_ids[NODE_0][WIT_V1][0], True)
-        self.fail_accept(self.nodes[0], p2sh_ids[NODE_0][WIT_V0][0], True)
-        self.fail_accept(self.nodes[0], p2sh_ids[NODE_0][WIT_V1][0], True)
+        self.fail_accept(self.nodes[0], "no-witness-yet", wit_ids[NODE_0][WIT_V0][0], True)
+        self.fail_accept(self.nodes[0], "no-witness-yet", wit_ids[NODE_0][WIT_V1][0], True)
+        self.fail_accept(self.nodes[0], "no-witness-yet", p2sh_ids[NODE_0][WIT_V0][0], True)
+        self.fail_accept(self.nodes[0], "no-witness-yet", p2sh_ids[NODE_0][WIT_V1][0], True)
 
         self.log.info("Verify witness txs are skipped for mining before the fork")
         self.skip_mine(self.nodes[2], wit_ids[NODE_2][WIT_V0][0], True) #block 424
@@ -203,8 +193,8 @@ class SegWitTest(BitcoinTestFramework):
         self.success_mine(self.nodes[2], wit_ids[NODE_2][WIT_V1][1], False) #block 429
 
         self.log.info("Verify unsigned p2sh witness txs without a redeem script are invalid")
-        self.fail_accept(self.nodes[2], p2sh_ids[NODE_2][WIT_V0][1], False)
-        self.fail_accept(self.nodes[2], p2sh_ids[NODE_2][WIT_V1][1], False)
+        self.fail_accept(self.nodes[2], "mandatory-script-verify-flag", p2sh_ids[NODE_2][WIT_V0][1], False)
+        self.fail_accept(self.nodes[2], "mandatory-script-verify-flag", p2sh_ids[NODE_2][WIT_V1][1], False)
 
         self.log.info("Verify unsigned p2sh witness txs with a redeem script in versionbits-settings blocks are valid before the fork")
         self.success_mine(self.nodes[2], p2sh_ids[NODE_2][WIT_V0][1], False, witness_script(False, self.pubkey[2])) #block 430
@@ -457,10 +447,13 @@ class SegWitTest(BitcoinTestFramework):
         importlist.append(bytes_to_hex_str(p2wshop1))
 
         for i in importlist:
+            # import all generated addresses. The wallet already has the private keys for some of these, so catch JSON RPC
+            # exceptions and continue.
             try:
                 self.nodes[0].importaddress(i,"",False,True)
             except JSONRPCException as exp:
                 assert_equal(exp.error["message"], "The wallet already contains the private key for this address or script")
+                assert_equal(exp.error["code"], -4)
 
         self.nodes[0].importaddress(script_to_p2sh(op0)) # import OP_0 as address only
         self.nodes[0].importaddress(multisig_without_privkey_address) # Test multisig_without_privkey
@@ -475,12 +468,7 @@ class SegWitTest(BitcoinTestFramework):
         # note that no witness address should be returned by unsolvable addresses
         # the multisig_without_privkey_address will fail because its keys were not added with importpubkey
         for i in uncompressed_spendable_address + uncompressed_solvable_address + unknown_address + unsolvable_address + [multisig_without_privkey_address]:
-            try:
-                self.nodes[0].addwitnessaddress(i)
-            except JSONRPCException as exp:
-                assert_equal(exp.error["message"], "Public key or redeemscript not known to wallet, or the key is uncompressed")
-            else:
-                assert(False)
+            assert_raises_jsonrpc(-4, "Public key or redeemscript not known to wallet, or the key is uncompressed", self.nodes[0].addwitnessaddress, i)
 
         for i in compressed_spendable_address + compressed_solvable_address:
             witaddress = self.nodes[0].addwitnessaddress(i)
@@ -559,12 +547,8 @@ class SegWitTest(BitcoinTestFramework):
         # note that a multisig address returned by addmultisigaddress is not solvable until it is added with importaddress
         # premature_witaddress are not accepted until the script is added with addwitnessaddress first
         for i in uncompressed_spendable_address + uncompressed_solvable_address + premature_witaddress + [compressed_solvable_address[1]]:
-            try:
-                self.nodes[0].addwitnessaddress(i)
-            except JSONRPCException as exp:
-                assert_equal(exp.error["message"], "Public key or redeemscript not known to wallet, or the key is uncompressed")
-            else:
-                assert(False)
+            # This will raise an exception
+            assert_raises_jsonrpc(-4, "Public key or redeemscript not known to wallet, or the key is uncompressed", self.nodes[0].addwitnessaddress, i)
 
         # after importaddress it should pass addwitnessaddress
         v = self.nodes[0].validateaddress(compressed_solvable_address[1])
diff --git a/qa/rpc-tests/wallet.py b/qa/rpc-tests/wallet.py
index 00fe37563b..80f74fa108 100755
--- a/qa/rpc-tests/wallet.py
+++ b/qa/rpc-tests/wallet.py
@@ -71,7 +71,7 @@ class WalletTest (BitcoinTestFramework):
         unspent_0 = self.nodes[2].listunspent()[0]
         unspent_0 = {"txid": unspent_0["txid"], "vout": unspent_0["vout"]}
         self.nodes[2].lockunspent(False, [unspent_0])
-        assert_raises_message(JSONRPCException, "Insufficient funds", self.nodes[2].sendtoaddress, self.nodes[2].getnewaddress(), 20)
+        assert_raises_jsonrpc(-4, "Insufficient funds", self.nodes[2].sendtoaddress, self.nodes[2].getnewaddress(), 20)
         assert_equal([unspent_0], self.nodes[2].listlockunspent())
         self.nodes[2].lockunspent(True, [unspent_0])
         assert_equal(len(self.nodes[2].listlockunspent()), 0)
@@ -251,19 +251,11 @@ class WalletTest (BitcoinTestFramework):
         txObj = self.nodes[0].gettransaction(txId)
         assert_equal(txObj['amount'], Decimal('-0.0001'))
 
-        try:
-            txId  = self.nodes[0].sendtoaddress(self.nodes[2].getnewaddress(), "1f-4")
-        except JSONRPCException as e:
-            assert("Invalid amount" in e.error['message'])
-        else:
-            raise AssertionError("Must not parse invalid amounts")
+        # This will raise an exception because the amount type is wrong
+        assert_raises_jsonrpc(-3, "Invalid amount", self.nodes[0].sendtoaddress, self.nodes[2].getnewaddress(), "1f-4")
 
-
-        try:
-            self.nodes[0].generate("2")
-            raise AssertionError("Must not accept strings as numeric")
-        except JSONRPCException as e:
-            assert("not an integer" in e.error['message'])
+        # This will raise an exception since generate does not accept a string
+        assert_raises_jsonrpc(-1, "not an integer", self.nodes[0].generate, "2")
 
         # Import address and private key to check correct behavior of spendable unspents
         # 1. Send some coins to generate new UTXO
@@ -394,7 +386,7 @@ class WalletTest (BitcoinTestFramework):
 
         node0_balance = self.nodes[0].getbalance()
         # With walletrejectlongchains we will not create the tx and store it in our wallet.
-        assert_raises_message(JSONRPCException, "mempool chain", self.nodes[0].sendtoaddress, sending_addr, node0_balance - Decimal('0.01'))
+        assert_raises_jsonrpc(-4, "Transaction has too long of a mempool chain", self.nodes[0].sendtoaddress, sending_addr, node0_balance - Decimal('0.01'))
 
         # Verify nothing new in wallet
         assert_equal(total_txs, len(self.nodes[0].listtransactions("*",99999)))