cargo-build-before-test

Detects redundant cargo build steps that immediately precede cargo test with identical build conditions.

This rule looks for:

• a cargo build step
• followed within 3 steps by cargo test
• where both commands use the same profile, target, features, package scope, and target selection
• where cargo test does not use --no-run

Why it matters:

• cargo test compiles the required test targets automatically.
• A preceding cargo build with identical conditions usually rebuilds the same artifacts and adds avoidable compile time.
• On larger Rust repositories this can add noticeable wall-clock and CPU time.

What to do:

• Remove the redundant cargo build step.
• If you need an explicit compile phase, use cargo test --no-run instead.
• Compare job runtime with and without the cargo build step.

Exceptions:

• This rule does not flag when cargo test --no-run is present, because that explicitly requests a compile-only phase.
• This rule does not flag when build conditions differ (profile, target, features, package scope, or target selection), because the build may serve a different purpose.