Write Scrut Tests

Scrut Test Style Guide

Apply the scrut test conventions from ./references/SCRUT.md when creating or editing scrut CLI test files.

Key Conventions

Read ./references/SCRUT.md for the complete guide. Summary:

File Organization

• Place tests in tests/scrut/ at the repository root
• One file per behavior group (help.md, error-handling.md, flag-validation.md)
• Use kebab-case.md file names describing the behavior tested

Test Structure

• One logical assertion per scrut block for precise failure locations
• Use > continuation prefix to split long &&-chained commands across lines
• Order blocks: happy path first, then common variations, then edge cases, then errors
• Level-1 heading for the test group, level-2 headings for individual test cases

Binary Invocation

• Always reference the binary via "${TOOL_BIN}" environment variable, never by path
• Use NO_COLOR=1 for commands that may produce colored output
• Use $(mktemp -d) for commands that create files

Assertion Selection

• Exact match (default) for stable, deterministic output like help text
• (glob) for dynamic values: versions, timestamps, commit hashes, paths
• (glob+) for variable-length sections you want to acknowledge but not pin
• (regex) only when glob patterns are insufficient
• Prefer NO_COLOR=1 over (escaped) matching for colored output

Error Testing

• Always include the expected exit code: [1]
• Redirect stderr to stdout: 2>&1
• Pipe through head -1 for long error output with usage text
• Use {output_stream: stderr} attribute as an alternative to redirection

Maintainability

• Pin help text and error messages exactly (catches regressions in user-facing text)
• Use glob for values that change between builds (versions, hashes, timestamps)
• Review diffs after make test-scrut-update to ensure glob/regex patterns were not replaced with literals

Zsh Plugin and Library Testing

For testing zsh plugins and sourced library code with scrut, read ./references/zsh-plugin-testing.md. Key points:

• Use --shell zsh flag with scrut test and scrut update
• Use source "${TESTDIR}/path/to/file.zsh" instead of "${TOOL_BIN}"
• Each scrut block supports only one $ line; additional $ lines are treated as expected output
• Do not set ERR_EXIT at file level; use emulate -LR zsh with strict options inside functions
• Chain source and function calls with && on the same command line

Validation

After writing or editing scrut tests, run them to verify:

make test-scrut

If snapshots need updating after intentional output changes:

make test-scrut-update