2 unstable releases

Uses new Rust 2024

new 0.3.0	May 6, 2026
0.2.0	May 2, 2026

#486 in Cargo plugins

MIT/Apache

90KB
2.5K SLoC

cargo-test-lint

AST-driven test quality linter for Rust. Catches common test anti-patterns at compile time using tree-sitter parsing.

Quick Start

cargo install cargo-test-lint
cargo test-lint

Rules

Rule	ID	Default	Description
Assertion Roulette	`assertion-roulette`	warn	`assert!`/`assert_eq!`/`assert_ne!` without context message
Max Expects	`max-expects`	warn	Test has too many assertions (default threshold: 5)
Sleepy Test	`sleepy-test`	forbid	`std::thread::sleep` in test code
Test Branching	`test-branching`	warn	`if`/`match` in test body (tests should be deterministic)
Async Blocking	`async-blocking`	warn	Blocking call in `#[tokio::test]`
Nested Mod	`nested-mod`	warn	Deeply nested test module (default max depth: 3)
Unnecessary Clone	`unnecessary-clone`	warn	`.clone()` on value that isn't reused
Deep Wrapper	`deep-wrapper`	warn	Type wrapper nested >3 levels deep
Missing Drop Guard	`missing-drop-guard`	warn	Resource allocation without RAII binding
Dead Test Helper	`dead-test-helper`	warn	Unused function/struct in test module
Static Mut	`static-mut`	warn	`static mut` variable (incompatible with nextest)
Env Set Var	`env-set-var`	warn	`std::env::set_var` in test (unsafe with nextest)
String Literal Corpus	`string-literal-corpus`	warn	Test corpus code embedded in string literals
Filesystem IO	`fs-io-in-test`	warn	`std::fs` calls in test (flakiness)

Configuration

Add to Cargo.toml (workspace or package level):

[lints.cargo-test-lint]
max-expects = 10
max-nested-mod = 2
deny-warnings = true

[lints.cargo-test-lint.rules]
sleepy-test = "deny"
test-branching = "allow"

Options

max-expects — Max assertions per test before warning (0 disables, default: 5)
max-nested-mod — Max nesting depth for test modules (0 disables, default: 3)
nextest — Enable nextest-specific checks
deny-warnings — Exit with error if any warnings found
rules — Per-rule level overrides: allow, warn, deny, forbid

CLI Flags

cargo test-lint [OPTIONS]

Options:
  --project-root <PATH>  Project root [default: .]
  --fix                  Auto-fix where possible
  --rules <RULES>        Filter rules
  --format <FORMAT>      Output format: terminal, sarif [default: terminal]
  --max-expects <N>      Override max assertions threshold
  --nextest              Enable nextest checks
  --deny-warnings        Treat warnings as errors

Output Formats

Terminal (default) — Colored diagnostics for local development.

SARIF — Static Analysis Results Interchange Format for CI and tool integration.

IDE Integration

rust-analyzer

Add to .vscode/settings.json:

{
  "rust-analyzer.check.command": "cargo test-lint"
}

Diagnostics appear inline as you edit.

Architecture

Single crate using tree-sitter for AST parsing. See ARCHITECTURE.md.

Property-Based Testing

This project uses proptest for property-based testing (PBT).

Conventions

Location: Property tests live alongside unit tests in the same module or in tests/ for integration-level properties.
Generator naming: All strategy/allocator functions use the arb_ prefix (e.g., arb_path(), arb_config()).
Case counts:
- Local development: 256 cases (proptest default).
- CI: 1000 cases via PROPTEST_CASES=1000 environment variable.
Shrinking: max_shrink_iters: 10000 configured for thorough minimization in CI.
Running: CI uses cargo test -- --include-ignored to ensure all PBT tests execute.

Example

use proptest::prelude::*;

fn arb_identifier() -> impl Strategy<Value = String> {
    proptest::string::string_regex("[a-z][a-z0-9_]{0,30}").unwrap()
}

proptest! {
    #![proptest_config(common::proptest_config())]

    #[test]
    fn identifier_never_empty(ref s in arb_identifier()) {
        assert!(!s.is_empty());
    }
}

License

MIT OR Apache-2.0

Dependencies

~12–17MB
~392K SLoC