test: add bounds checking for submitpackage RPC

Author: stickies-v

test/functional/rpc_packages.py

@@ -25,6 +25,9 @@
 )
 
 
+MAX_PACKAGE_COUNT = 25
+
+
 class RPCPackagesTest(BitcoinTestFramework):
     def set_test_params(self):
         self.num_nodes = 1
@@ -340,6 +343,13 @@ def test_submitpackage(self):
         assert_raises_rpc_error(-25, "package topology disallowed", node.submitpackage, chain_hex)
         assert_equal(legacy_pool, node.getrawmempool())
 
+        assert_raises_rpc_error(-8, f"Array must contain between 1 and {MAX_PACKAGE_COUNT} transactions.", node.submitpackage, [])
+        assert_raises_rpc_error(-25, "package topology disallowed", node.submitpackage, [chain_hex[0]] * 1)
+        assert_raises_rpc_error(
+            -8, f"Array must contain between 1 and {MAX_PACKAGE_COUNT} transactions.",
+            node.submitpackage, [chain_hex[0]] * (MAX_PACKAGE_COUNT + 1)
+        )
+
         # Create a transaction chain such as only the parent gets accepted (by making the child's
         # version non-standard). Make sure the parent does get broadcast.
         self.log.info("If a package is partially submitted, transactions included in mempool get broadcast")