specdiff

Show how the test outline of a project has changed on a branch.

Parses test files from two VCS revisions using tree-sitter, normalizes them into a language-agnostic tree, diffs the trees with rename detection, and presents the structural diff as CLI output or a real-time TUI.

Features

Multi-framework support: RSpec, Minitest, pytest, Jest/Vitest/Mocha, Go testing, Rust #[test], ExUnit — defined declaratively in TOML
Git and Jujutsu (jj) support with automatic backend detection
Tree-sitter parsing for accurate, syntax-aware test discovery
Shared example resolution (RSpec shared_examples, pytest conftest)
Rename detection with similarity scoring
Parameterized test awareness (rstest, pytest.mark.parametrize, Jest .each)
Output formats: colored tree (default), JSON, compact
Watch mode TUI with live refresh on file changes

Requirements

Git: Any reasonably modern git (1.7+)
Jujutsu (optional): If a .jj directory is present, specdiff uses jj automatically

Installation

Homebrew (macOS/Linux)

brew tap michaeldhopkins/tap
brew install specdiff

From source

cargo install --git https://github.com/michaeldhopkins/specdiff

Manual download

Download binaries from GitHub Releases.

Usage

specdiff

Run in a git/jj repository. Opens a TUI that shows test outline changes on the current branch and live-refreshes when test files change.

Keybindings: q quit, c toggle changed-only, j/k scroll, PgUp/PgDn page scroll.

Non-interactive output

specdiff --print
specdiff -p --format json
specdiff -p --format compact

Options

Flag	Description
`-p`, `--print`	Print diff to stdout and exit (non-interactive)
`--base <REV>`	Base revision (default: auto-detected)
`--head <REV>`	Head revision (default: working copy)
`--format <FORMAT>`	Output format: `tree` (default), `json`, `compact`
`--changed-only`	Only show changed specs
`--framework <NAME>`	Force a specific framework
`--filter <PATTERN>`	Filter specs by name pattern
`--no-color`	Disable colored output
`-h`, `--help`	Print help
`-V`, `--version`	Print version

Example output

models::User
+   validates uniqueness of username
    validates email format
->  requires password -> validates password length
~   associations
+     has many comments
      has many posts
+ requests::admin
+   DELETE /users/:id returns 403

Legend: + added, - removed, -> renamed, ~ modified (children changed)

Supported Frameworks

Framework	Language	Detection
RSpec	Ruby	DSL (`describe`/`it`/`context`)
Minitest	Ruby	Class names (`Test`) + method names (`test_`)
pytest	Python	Class names (`Test`) + function names (`test_`)
Jest / Vitest / Mocha	JavaScript/TypeScript	DSL (`describe`/`it`/`test`)
Go testing	Go	Function names (`Test*`) + `t.Run` subtests
Rust built-in	Rust	`#[test]` + `#[cfg(test)]` attributes
rstest	Rust	`#[rstest]` parameterized tests
proptest	Rust	`proptest!` macro
ExUnit	Elixir	DSL (`describe`/`test`)

Framework knowledge is defined in TOML data files under frameworks/. Adding a new framework requires only a new TOML file in most cases.

Contributing

Requires Rust 1.85+.

cargo build
cargo test
cargo clippy --all-targets -- -D warnings
cargo deny check licenses

License

Dual-licensed under MIT or Apache-2.0.

specdiff 0.16.0