adamchalmers
commented
3 months ago Current plan is:
- The CI image (and local dev, if you're running tests locally) will require starting a server. Start it with
cargo run kcl-test-server. - That server connects to the engine, and listens for incoming KCL programs over localhost:3333. When it gets a HTTP request, it gets a KCL file from the request body, executes it on the engine, and serves a PNG snapshot in response.
- The unit tests will send their KCL files over localhost:3333 and get a PNG file back. Then call 2020 on that PNG as usual.
Nextest has experimental support for setup scripts (docs, tracking issue: https://github.com/nextest-rs/nextest/issues/978). If we use it, then Nextest would automatically start the test server if you run a test that requires it. Could be nice.
If we don't want to use the experimental nextest feature, then we just kcl-test-server in GitHub Actions, and print a nice error message in the unit tests if the server isn't found.
I've got a POC here: https://github.com/KittyCAD/modeling-app/pull/2627
Background
Currently every Rust unit test creates a new kittycad client, starting a new session with the engine.
Problem
This seems inefficient -- it would add a lot of latency from starting and stopping engine sessions.
Solution
Before running any tests, start a test server. The test server has one HTTP endpoint which takes a KCL program, executes it, and responds with a PNG snapshot. It does this by running a KCL executor.
Each test, instead of making its own KCL executor, just sends programs to this HTTP server. This way our suite of 100 tests only connects to the engine once, instead of 100 times -- should be much faster.