Add the beginnings of a peers.exchange test and begin to fix fallout.

src/tests.c

@@ -915,6 +915,7 @@ void tf_tests(const tf_test_options_t* options)
 	_tf_test_run(options, "auto", _test_auto, false);
 	_tf_test_run(options, "go-ssb-room", tf_ssb_test_go_ssb_room, true);
 	_tf_test_run(options, "encrypt", tf_ssb_test_encrypt, false);
+	_tf_test_run(options, "peer_exchange", tf_ssb_test_peer_exchange, false);
 	tf_printf("Tests completed.\n");
 #endif
 }