[qa] add assert_raises_message to check specific error message

qa/rpc-tests/test_framework/util.py

@@ -531,10 +531,14 @@ def assert_greater_than(thing1, thing2):
         raise AssertionError("%s <= %s"%(str(thing1),str(thing2)))
 
 def assert_raises(exc, fun, *args, **kwds):
+    assert_raises_message(exc, None, fun, *args, **kwds)
+
+def assert_raises_message(exc, message, fun, *args, **kwds):
     try:
         fun(*args, **kwds)
-    except exc:
-        pass
+    except exc as e:
+        if message is not None and message not in e.error['message']:
+            raise AssertionError("Expected substring not found:"+e.error['message'])
     except Exception as e:
         raise AssertionError("Unexpected exception raised: "+type(e).__name__)
     else:

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(JSONRPCException, self.nodes[2].sendtoaddress, self.nodes[2].getnewaddress(), 20)
+        assert_raises_message(JSONRPCException, "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)