diff --git a/common/test/run-json.c b/common/test/run-json.c
index e599a0f59..8c21ed7f1 100644
--- a/common/test/run-json.c
+++ b/common/test/run-json.c
@@ -4,7 +4,41 @@
 /* AUTOGENERATED MOCKS START */
 /* AUTOGENERATED MOCKS END */
 
-int main(void)
+
+// issue #577
+
+static void do_json_tok_bitcoin_amount(const char* val, uint64_t expected)
+{
+	uint64_t amount;
+	jsmntok_t tok;
+
+	tok.start = 0;
+	tok.end = strlen(val);
+
+	fprintf(stderr, "do_json_tok_bitcoin_amount(\"%s\", %"PRIu64"): ", val, expected);
+
+	assert(json_tok_bitcoin_amount(val, &tok, &amount) == true);
+	assert(amount == expected);
+
+	fprintf(stderr, "ok\n");
+}
+
+
+static int test_json_tok_bitcoin_amount(void)
+{
+	do_json_tok_bitcoin_amount("0.00000001", 1);
+	do_json_tok_bitcoin_amount("0.00000007", 7);
+	do_json_tok_bitcoin_amount("0.00000008", 8);
+	do_json_tok_bitcoin_amount("0.00000010", 10);
+	do_json_tok_bitcoin_amount("0.12345678", 12345678);
+	do_json_tok_bitcoin_amount("0.01234567", 1234567);
+	do_json_tok_bitcoin_amount("123.45678900", 12345678900);
+
+	return 0;
+}
+
+
+static int test_json_escape(void)
 {
 	struct json_result *result = new_json_result(NULL);
 	jsmntok_t *toks;
@@ -43,3 +77,10 @@ int main(void)
 	tal_free(result);
 	return 0;
 }
+
+
+int main(void)
+{
+	test_json_tok_bitcoin_amount();
+	test_json_escape();
+}