1 files changed, 74 insertions, 0 deletions
diff --git a/tests/test_dissector.cpp b/tests/test_dissector.cpp
new file mode 100644
index 0000000..9dd4135
--- /dev/null
+++ b/tests/test_dissector.cpp
@@ -0,0 +1,74 @@
+#include <doctest/doctest.h>
+
+#include "packeteer/l7/dissector.hpp"
+
+using namespace packeteer::net;
+
+namespace {
+
+// A dissector that claims a port but never actually matches any
+// payload - stands in for e.g. TlsSniDissector receiving QUIC bytes
+// on port 443: same port, wrong protocol, never succeeds.
+class NeverMatchesDissector : public L7Dissector {
+public:
+    explicit NeverMatchesDissector(std::uint16_t port) : port_(port) {}
+    std::uint16_t port() const override { return port_; }
+    std::optional<std::string> summarize(std::span<const unsigned char>) const override {
+        return std::nullopt;
+    }
+
+private:
+    std::uint16_t port_;
+};
+
+class AlwaysMatchesDissector : public L7Dissector {
+public:
+    AlwaysMatchesDissector(std::uint16_t port, std::string label)
+        : port_(port), label_(std::move(label)) {}
+    std::uint16_t port() const override { return port_; }
+    std::optional<std::string> summarize(std::span<const unsigned char>) const override {
+        return label_;
+    }
+
+private:
+    std::uint16_t port_;
+    std::string label_;
+};
+
+}  // namespace
+
+TEST_CASE("L7Registry falls through to a later dissector on the same port "
+          "when an earlier one fails to match") {
+    NeverMatchesDissector tls_like(443);
+    AlwaysMatchesDissector quic_like(443, "QUIC something");
+
+    L7Registry registry;
+    registry.add(&tls_like);
+    registry.add(&quic_like);
+
+    auto result = registry.dissect(443, {});
+    REQUIRE(result.has_value());
+    CHECK(*result == "QUIC something");
+}
+
+TEST_CASE("L7Registry still returns the first dissector to succeed, not the last") {
+    AlwaysMatchesDissector first(80, "first");
+    AlwaysMatchesDissector second(80, "second");
+
+    L7Registry registry;
+    registry.add(&first);
+    registry.add(&second);
+
+    auto result = registry.dissect(80, {});
+    REQUIRE(result.has_value());
+    CHECK(*result == "first");
+}
+
+TEST_CASE("L7Registry returns nullopt when no dissector on the port matches") {
+    NeverMatchesDissector only(443);
+
+    L7Registry registry;
+    registry.add(&only);
+
+    CHECK_FALSE(registry.dissect(443, {}).has_value());
+}