Charter — AI-Agent Readiness Scanner

Rule ID: AE-TEST-001 · Severity: High · Category: Testing · Auto-fixable: No

Why this rule

An agent that writes code in a language with no automated tests has no way to verify its own work. Tests are the agent’s exit condition — without them it can only produce a diff, not a proof. The AGENTS.md standard treats the test command as one of the highest-value pieces of context an agent can have. AE-TEST-001 checks that there is actually something to run — before AE-AUTO-001 checks that the command is discoverable.

What triggers it

Charter detects active languages from manifest files committed to the repo:

Language	Manifest
Go	`go.mod`
JavaScript / TypeScript	`package.json`
Rust	`Cargo.toml`
Python	`pyproject.toml` or `requirements.txt`
Java / Kotlin	`pom.xml` or `build.gradle`
Ruby, C#, PHP	Equivalents

A language is only active when its manifest is present and the repo contains at least one non-test source file for that language outside tooling directories (scripts/, vendor/, node_modules/, dist/, build/). For each active language, Charter checks whether at least one test file exists using standard naming conventions:

Language	Test file patterns
Go	`*_test.go`
JavaScript / TypeScript	`.test.`, `.spec.`
Python	`test_.py`, `_test.py`, `conftest.py`
Rust	Files under `tests/`, inline `#[cfg(test)]` markers
Java / Kotlin	`Test.java`, `Test.kt`

Files in directories named test/, tests/, spec/, or __tests__/ also count, regardless of language.

Charter detects active languages by manifest, not by line count. A go.mod with one .go source file (non-test) counts as an active language and requires at least one test file.

Examples

Failing
Passing

A Go module with source files under internal/ but no *_test.go file anywhere:

my-service/
├── go.mod
├── internal/
│   ├── scorer.go
│   └── parser.go
└── cmd/
    └── main.go
# no *_test.go files → flagged High

A TypeScript project with source files but no test files:

my-app/
├── package.json
├── src/
│   └── index.ts
# no *.test.ts, *.spec.ts, or __tests__/ → flagged High

Go module with at least one test file:

my-service/
├── go.mod
├── internal/
│   ├── scorer.go
│   └── scorer_test.go  ✓

TypeScript project with a test directory:

my-app/
├── package.json
├── src/
│   └── index.ts
└── __tests__/
    └── index.test.ts  ✓

Rust crate with inline unit tests — #[cfg(test)] blocks count:

src/lib.rs

pub fn add(a: i32, b: i32) -> i32 { a + b }

#[cfg(test)]
mod tests {
    use super::*;
    #[test]
    fn test_add() { assert_eq!(add(2, 3), 5); }
}

How to fix

Add a minimal test file for each active language that Charter flags. The test does not need comprehensive coverage — Charter checks for presence, not coverage percentage or pyramid shape.

Identify the active languages

Run charter doctor or charter explain AE-TEST-001 to see which languages are flagged and which manifest triggered each one.

Add a minimal test file

Create at least one test file using the language’s standard naming convention. A single passing test satisfies the rule.

Verify the finding clears

Run charter doctor again to confirm the finding no longer appears.

Score impact

High (−10); no hard cap. If multiple active languages all lack tests, each fires a separate finding instance.

Edge cases

Docs, config, and tooling-only repos

AE-TEST-001 does not fire when no recognized code language is active. A repo containing only Markdown, YAML config, or tooling scripts is not penalized.

Embedded web assets in Go binaries

A //go:embed’d web asset (e.g. a report.js embedded into a Go binary) is a bundled resource, not a language surface. It does not activate JavaScript/TypeScript even when a build-tooling package.json is present.

Stray secondary-language files

A lone *.rb Homebrew formula with no Gemfile, or a stray *.py helper with no pyproject.toml, is not an active language and does not require tests.

Rust inline tests

Rust inline unit tests count via the #[cfg(test)] / #[test] content signal — no separate tests/ directory is required.

AE-AUTO-001

Requires a discoverable command to run the tests that this rule checks for.

AE-CI-002

Requires CI to run those tests on every pull request.

CLI

charter explain AE-TEST-001

​Why this rule

​What triggers it

​Examples

​How to fix

​Score impact

​Edge cases

​Related rules

AE-AUTO-001

AE-CI-002

​CLI

Why this rule

What triggers it

Examples

How to fix

Score impact

Edge cases

Related rules

CLI