rust/tests/run-make/README.md

The run-make test suite

The run-make test suite contains tests which are the most flexible out of all the rust-lang/rust test suites. run-make tests can basically contain arbitrary code, and are supported by the run_make_support library.

Infrastructure

There are two kinds of run-make tests:

1. The new rmake.rs version: this allows run-make tests to be written in Rust (with rmake.rs as the main test file).
2. The legacy Makefile version: this is what run-make tests were written with before support for rmake.rs was introduced.

The implementation for collecting and building the rmake.rs recipes (or Makefiles) are in src/tools/compiletest/src/runtest.rs, in run_rmake_v2_test and run_rmake_legacy_test.

Rust-based run-make tests: rmake.rs

The setup for the rmake.rs version is a 3-stage process:

1. First, we build the run_make_support library in bootstrap as a tool lib.

2. Then, we compile the rmake.rs "recipe" linking the support library and its dependencies in, and provide a bunch of env vars. We setup a directory structure within build/<target>/test/run-make/

   <test-name>/
       rmake.exe              # recipe binary
       rmake_out/             # sources from test sources copied over
   

   and copy non-rmake.rs input support files over to rmake_out/. The support library is made available as an extern prelude.

3. Finally, we run the recipe binary and set rmake_out/ as the working directory.