Development

Prerequisites

Rust (edition 2024, see rust-toolchain.toml for pinned version)
wasm32-unknown-unknown target: rustup target add wasm32-unknown-unknown
Dioxus CLI: cargo install dioxus-cli or cargo binstall dioxus-cli
Node.js / npm (for Tailwind CSS — see issue #12)

Local Development

# Install Tailwind CSS dependencies (required before any cargo command).
# build.rs compiles Tailwind CSS via `npx @tailwindcss/cli`.
npm ci

# Start Dioxus dev server (web target)
# Tailwind CSS is compiled by build.rs via `npx @tailwindcss/cli` so that
# every cargo invocation (clippy, test, coverage, dx serve, etc.) works
# without relying on the Dioxus CLI's bundled Tailwind.
# See: https://github.com/altendky/mujou/issues/12
#
# Shared theme assets (site/theme.css, site/theme-toggle.js, site/theme-detect.js)
# are copied to OUT_DIR by build.rs and injected via include_str!().
# build.rs also generates crates/mujou-app/index.html (gitignored) with the
# theme-detect script inlined in <head> to prevent flash of wrong theme.
dx serve --platform web --package mujou-app

# Format
cargo fmt

# Lint
cargo clippy --all-targets --all-features -- -D warnings

# Test core crates (no WASM runtime needed)
cargo nextest run --all-features

# Coverage
cargo llvm-cov --all-features --workspace

Installing Development Tools

# Dioxus CLI
cargo install dioxus-cli

# cargo-nextest (test runner)
cargo install cargo-nextest --locked

# cargo-llvm-cov (coverage)
cargo install cargo-llvm-cov --locked

# cargo-deny (dependency audit)
cargo install cargo-deny --locked

Testing Strategy

Test Type	Location	Coverage Target
Unit tests	`crates//src//.rs`	100% with exclusions
Integration tests	`crates/mujou-app/tests/`	Key workflows

Core Crate Testing

Core crates (mujou-pipeline, mujou-export) are fully testable without a browser or WASM runtime. All functions are pure: deterministic inputs produce deterministic outputs.

# Test just the pipeline crate
cargo nextest run -p mujou-pipeline

# Test just the export crate
cargo nextest run -p mujou-export

Test Patterns

Synthetic test images (e.g., a white rectangle on black background) for predictable edge detection output
Known-good polyline inputs for export format tests
Round-trip tests where applicable (e.g., export to SVG, verify SVG structure)

Coverage Requirements

Tool: cargo-llvm-cov
Target: 100% with explicit exclusions for untestable code
Enforcement: Ratchet – fail if coverage drops more than 2% from main; new code must be fully covered or explicitly excluded

Coverage Exclusions

Use LCOV comments with justification:

#![allow(unused)]
fn main() {
// Platform-specific WASM code not testable in native tests
some_wasm_only_code(); // LCOV_EXCL_LINE

// LCOV_EXCL_START -- web-sys DOM interaction, tested manually in browser
fn trigger_download(...) { ... }
// LCOV_EXCL_STOP
}

Workspace Lints

[workspace.lints.rust]
unsafe_code = "deny"

[workspace.lints.clippy]
pedantic = { level = "warn", priority = -1 }
nursery = { level = "warn", priority = -1 }
unwrap_used = "deny"
expect_used = "deny"
panic = "deny"

Pre-commit Hooks

Philosophy: Pre-commit hooks provide developers an opt-in mechanism for fast local feedback. They do not enforce policy – CI is the source of truth.

Hook	Stage	Purpose
`trailing-whitespace`	pre-commit	Clean whitespace
`end-of-file-fixer`	pre-commit	Consistent EOF
`check-toml`	pre-commit	TOML syntax
`check-yaml`	pre-commit	YAML syntax
`check-merge-conflict`	pre-commit	Catch conflict markers
`typos`	pre-commit	Spell checking
`markdownlint-cli2`	pre-commit	Markdown linting
`cargo fmt --check`	pre-commit	Formatting
`cargo clippy`	pre-commit	Linting
`cargo nextest run`	manual	Tests
`cargo deny`	manual	Dependency audit

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