testing

Testing guidelines and patterns for skia-rs.

Cursor rule for Cursor

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add rules/quinnjr/skia-rs/testing
Clone the repo
git clone --depth 1 https://github.com/quinnjr/skia-rs

Made for: Cursor.

Per session 0 Nothing until a file matches its globs; then the whole rule loads.
When invoked 375 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00000 $0.00375
Opus 5 $0.00000 $0.00187
Sonnet 5 $0.00000 $0.00075
Haiku 4.5 $0.00000 $0.00038

Measured yesterday against content hash c7cf46339ddb, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

testing scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured yesterday.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

.cursor/rules/testing.mdc · 63 lines

What it actually says

Testing Guidelines

Unit Tests

  • Place tests in the same file as the code
  • Test edge cases and error conditions
  • Use property-based testing with proptest for numeric code
#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn point_addition() {
        let p1 = Point::new(1.0, 2.0);
        let p2 = Point::new(3.0, 4.0);
        assert_eq!(p1 + p2, Point::new(4.0, 6.0));
    }
}

Property Testing

use proptest::prelude::*;

proptest! {
    #[test]
    fn matrix_identity_preserves_point(x in -1000.0f32..1000.0, y in -1000.0f32..1000.0) {
        let p = Point::new(x, y);
        let result = Matrix::IDENTITY.map_point(p);
        prop_assert!((result.x - p.x).abs() < 1e-6);
        prop_assert!((result.y - p.y).abs() < 1e-6);
    }
}

Conformance Testing

  • Compare output against Skia reference implementation
  • Use the skia/ submodule for reference
  • Document any intentional behavioral differences

Running Tests

# Run all tests
cargo test --workspace

# Run tests for a specific crate
cargo test -p skia-rs-core

# Run with output
cargo test --workspace -- --nocapture
Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. yesterday First seen · 63 lines · 0 tokens per session scan A c7cf46339ddb

Subscribe to this mod's changes

testing is a cursor rule published in the GitHub repository quinnjr/skia-rs (31 stars, last pushed 13d ago), licensed Apache-2.0. It costs nothing until one of its globs matches a file; then it loads 375 tokens. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-09-01.