Add tests for new JoinSplit keys returned by z_listreceivedbyaddress

qa/rpc-tests/zkey_import_export.py

@@ -89,6 +89,12 @@ class ZkeyImportExportTest (BitcoinTestFramework):
 
             try:
                 assert_equal(amts, [tx["amount"] for tx in txs])
+                for tx in txs:
+                    # make sure JoinSplit keys exist and have valid values
+                    assert_equal( "jsindex" in tx, True)
+                    assert_equal( "jsoutindex" in tx, True)
+                    assert_greater_than( tx["jsindex"], -1 )
+                    assert_greater_than( tx["jsoutindex"], -1 )
             except AssertionError:
                 logging.error(
                     'Expected amounts: %r; txs: %r',