test: add two edge case tests for CSubNet

Author: vasild

src/test/netbase_tests.cpp

@@ -160,6 +160,9 @@ BOOST_AUTO_TEST_CASE(subnet_test)
     BOOST_CHECK(ResolveSubNet("1.2.2.20/26").Match(ResolveIP("1.2.2.63")));
     // All-Matching IPv6 Matches arbitrary IPv4 and IPv6
     BOOST_CHECK(ResolveSubNet("::/0").Match(ResolveIP("1:2:3:4:5:6:7:1234")));
+    // But not `::` or `0.0.0.0` because they are considered invalid addresses
+    BOOST_CHECK(!ResolveSubNet("::/0").Match(ResolveIP("::")));
+    BOOST_CHECK(!ResolveSubNet("::/0").Match(ResolveIP("0.0.0.0")));
     BOOST_CHECK(ResolveSubNet("::/0").Match(ResolveIP("1.2.3.4")));
     // All-Matching IPv4 does not Match IPv6
     BOOST_CHECK(!ResolveSubNet("0.0.0.0/0").Match(ResolveIP("1:2:3:4:5:6:7:1234")));