test: Default --previous-releases to false if dir is empty

test/functional/test_framework/test_framework.py

@@ -156,7 +156,7 @@ class BitcoinTestFramework(metaclass=BitcoinTestMetaClass):
         parser.add_argument("--portseed", dest="port_seed", default=os.getpid(), type=int,
                             help="The seed to use for assigning port numbers (default: current process id)")
         parser.add_argument("--previous-releases", dest="prev_releases", action="store_true",
-                            default=os.path.isdir(previous_releases_path),
+                            default=os.path.isdir(previous_releases_path) and bool(os.listdir(previous_releases_path)),
                             help="Force test of previous releases (default: %(default)s)")
         parser.add_argument("--coveragedir", dest="coveragedir",
                             help="Write tested RPC commands into this directory")