[qa] Test fundrawtransaction with change_type option

test/functional/fundrawtransaction.py

@@ -212,6 +212,19 @@ class RawTransactionsTest(BitcoinTestFramework):
         out = dec_tx['vout'][0]
         assert_equal(change, out['scriptPubKey']['addresses'][0])
 
+        #########################################################
+        # test a fundrawtransaction with a provided change type #
+        #########################################################
+        utx = get_unspent(self.nodes[2].listunspent(), 5)
+
+        inputs  = [ {'txid' : utx['txid'], 'vout' : utx['vout']} ]
+        outputs = { self.nodes[0].getnewaddress() : Decimal(4.0) }
+        rawtx   = self.nodes[2].createrawtransaction(inputs, outputs)
+        assert_raises_rpc_error(-1, "JSON value is not a string as expected", self.nodes[2].fundrawtransaction, rawtx, {'change_type': None})
+        assert_raises_rpc_error(-5, "Unknown change type", self.nodes[2].fundrawtransaction, rawtx, {'change_type': ''})
+        rawtx = self.nodes[2].fundrawtransaction(rawtx, {'change_type': 'bech32'})
+        tx  = self.nodes[2].decoderawtransaction(rawtx['hex'])
+        assert_equal('witness_v0_keyhash', tx['vout'][rawtx['changepos']]['scriptPubKey']['type'])
 
         #########################################################################
         # test a fundrawtransaction with a VIN smaller than the required amount #