add-scrut-cli-tests

Add Scrut CLI Tests

Set up scrut snapshot-based CLI integration testing for a CLI project with Makefile targets and CI workflow integration.

Prerequisites

• A CLI project that produces a binary or has an executable entry point
• A .github/workflows/ci.yml workflow (or equivalent CI workflow file) is recommended for CI integration

Workflow

1. Detect the Project Type

Identify the project language by checking for manifest files:

Marker(s)	Language
go.mod	Go
Package.swift	Swift
Cargo.toml	Rust
build.zig	Zig
pyproject.toml, setup.py	Python
Gemfile, *.gemspec	Ruby
Executable scripts (no manifest)	Shell

If no manifest is found and executable shell scripts exist in the root, bin/, or scripts/, treat the project as a shell script CLI.

If the project type cannot be determined, ask the user what language the project uses and where the binary or executable is located.

Check for an existing tests/scrut/ directory; if present, warn and ask whether to add to it or abort.

2. Gather Project Information

Collect the following, inferring from existing files where possible:

• Binary name: determine by project type:
  • Go: check the Makefile build target for the output binary name (look for -o bin/NAME or -o NAME), or derive from the last segment of the module path in go.mod
  • Swift: check Package.swift for executable target names, or check the Makefile build target
  • Rust: check Cargo.toml for [[bin]] entries or the name field under [package]
  • Zig: check build.zig for b.addExecutable(.{ .name = "..." }) and use the .name value, or use the directory name
  • Python: check pyproject.toml for [project.scripts] entries
  • Ruby: check the gemspec for executables or look in bin/ or exe/
  • Shell: use the script filename as the binary name
• Binary path: determine the full path used to run the binary:
  • Compiled languages (Go, Swift, Rust, Zig): typically bin/NAME or a build output directory (e.g., $(CURDIR)/bin/NAME for Go, $(CURDIR)/zig-out/bin/NAME for Zig)
  • Interpreted languages (Python, Ruby, Shell): the script path itself (e.g., bin/NAME, ./NAME)
• Environment variable name: derive from the binary name, uppercased with hyphens replaced by underscores, suffixed with _BIN (e.g., bopca becomes BOPCA_BIN, my-tool becomes MY_TOOL_BIN)
• Build required: whether a build step is needed before running tests (yes for compiled languages, no for interpreted languages)