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+# Interoperability test
+
+This tests that different libp2p implementations can communicate with each other
+on each of their supported capabilites.
+
+Each version of libp2p is defined in `versions.ts`. There the version defines
+its capabilities along with the id of its container image.
+
+# Test spec
+
+The implementation is run in a container and is passed parameters via
+environment variables. The current parameters are:
+
+| Name                 | Description                                                  | Is Optional                                                     |
+| -------------------- | ------------------------------------------------------------ | --------------------------------------------------------------- |
+| transport            | The transport to use                                         | no                                                              |
+| muxer                | The muxer to use                                             | no, except when transport is one of quic, quic-v1, webtransport |
+| security             | The security channel to use                                  | no, except when transport is one of quic, quic-v1, webtransport |
+| is_dialer            | Should you dial or listen                                    | no                                                              |
+| ip                   | IP address to bind the listener to                           | yes, default to "0.0.0.0"                                       |
+| redis_addr           | A different address to connect to redis (default redis:6379) | yes, default to the `redis` host on port 6379                   |
+| test_timeout_seconds | Control the timeout of test.                                 | yes, default to 180 seconds.                                    |
+
+The test should do two different things depending on if it's the dialer or
+listener.
+
+## Dialer
+
+The dialer should emit all diagnostic logs to `stderr`. Only the final JSON
+string result should be emitted to `stdout`.
+
+1. Connect to the Redis instance.
+2. Create a libp2p node as defined by the environment variables.
+3. Get the listener's address via Redis' `BLPOP` using the `listenerAddr` key.
+4. Record the current instant as `handshakeStartInstant`.
+5. Connect to the listener.
+6. Ping the listener, and record the round trip duration as `pingRTT`
+7. Record the duration since `handshakeStartInstant`. This is `handshakePlusOneRTT`.
+8. Print to `stdout` the JSON formatted string: `{"handshakePlusOneRTTMillis":
+   handshakePlusOneRTT, "pingRTTMilllis": pingRTT}`. Durations should be printed in
+   milliseconds as a float.
+9.  Exit with a code zero.
+
+On error, the dialer should return a non-zero exit code.
+
+## Listener
+
+The listener should emit all diagnostic logs to `stderr`.
+
+1. Connect to the Redis instance.
+2. Create a libp2p node as defined by the environment variables.
+3. Publish the listener's address via Redis' `RPUSH` using the `listenerAddr`
+   key.
+4. Sleep for the duration of `test_timeout_seconds`. The test runner will kill this
+   process when the dialer finishes.
+5. If the timeout is hit, exit with a non-zero error code.
+
+On error, the listener should return a non-zero exit code.
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