1# BoringSSL SSL Tests 2 3This directory contains BoringSSL's protocol-level test suite. 4 5Testing a TLS implementation can be difficult. We need to produce invalid but 6sufficiently correct handshakes to get our implementation close to its edge 7cases. TLS's cryptographic steps mean we cannot use a transcript and effectively 8need a TLS implementation on the other end. But we do not wish to litter 9BoringSSL with options for bugs to test against. 10 11Instead, we use a fork of the Go `crypto/tls` package, heavily patched with 12configurable bugs. This code, along with a test suite and harness written in Go, 13lives in the `runner` directory. The harness runs BoringSSL via a C/C++ shim 14binary which lives in this directory. All communication with the shim binary 15occurs with command-line flags, sockets, and standard I/O. 16 17This strategy also ensures we always test against a second implementation. All 18features should be implemented twice, once in C for BoringSSL and once in Go for 19testing. If possible, the Go code should be suitable for potentially 20upstreaming. However, sometimes test code has different needs. For example, our 21test DTLS code enforces strict ordering on sequence numbers and has controlled 22packet drop simulation. 23 24To run the tests manually, run `go test` from the `runner` directory. It takes 25command-line flags found at the top of `runner/runner.go`. The `-help` option 26also works after using `go test -c` to make a `runner.test` binary first. 27 28If adding a new test, these files may be a good starting point: 29 30 * `runner/runner.go`: the test harness and all the individual tests. 31 * `runner/common.go`: contains the `Config` and `ProtocolBugs` struct which 32 control the Go TLS implementation's behavior. 33 * `test_config.h`, `test_config.cc`: the command-line flags which control the 34 shim's behavior. 35 * `bssl_shim.cc`: the shim binary itself. 36 37For porting the test suite to a different implementation see 38[PORTING.md](./PORTING.md). 39