Josh Compose

"josh compose" is a subcommand of "josh" CLI that runs a set of commands in defined environments. The commands and environments are defined in .josh files, most of which are in the root of the repo in the /ws directory.

Obtaining access to josh binary

When josh is available in current environment, use that command. When it's not available, use cargo run --bin josh -- compose ... to run the command.

Test organization

This repo uses scrut tool to run integration tests. scrut is a tool for snapshot testing. The tool takes cram-style .t files where shell commands are defined along with their expected output. When the output changes, scrut detects it.

Test files live under tests/ and are organized by subsystem:

• tests/filter/ — filter language tests (largest suite)
• tests/proxy/ — git proxy tests
• tests/cli/ — CLI tests
• tests/experimental/ — excluded from release tests

Running tests via josh compose run

Tests run inside an isolated podman container. Step results are cached; the cache key is the SHA of the filtered workspace tree, so the cache is automatically invalidated when source files change.

Running all tests

josh compose run

To test a specific commit instead of the working tree, pass it as the first argument:

josh compose run HEAD

Other values you can pass include:

• . (default) — working tree, including uncommitted changes
• + — staged files (git index); useful to test only what you've git added
• HEAD — last commit, ignoring any local changes

Inspecting test output

Each test file prints a result line in the josh compose run output:

Result: 1 document(s) with N testcase(s): N succeeded, 0 failed and 0 skipped

Followed at the end by SUCCESS: <sha> or FAILED: <name>.

For failing tests, the scrut diff format shows the shell expression that failed, expected output (preceded by -), and actual output (preceded by +). The updated .t files are written back to the working directory, so you can inspect them directly.

Iterating on a failing test

1. Edit the .t test file or the relevant source code.
2. Re-run josh compose run — the changed working tree produces a new SHA, so the cache is bypassed automatically.

Do not use --clean or --clean-all

Never pass --clean or --clean-all to josh compose run. The cache is reliable; clearing it just forces a full rebuild and wastes time. If something seems wrong that you believe a cache wipe would fix, stop and ask the user to run the clean in a separate terminal — do not run it yourself, ever.