dev-coverage 0.1.0

What it does

dev-coverage runs cargo-llvm-cov against your project, parses the output, and emits results as dev-report::Report. It detects coverage regressions against a stored baseline and produces a CheckResult that AI agents and CI gates can act on.

Why a separate crate

Test coverage is the single most important metric for understanding test quality. Without it, you don't know how much of your code is actually exercised. With it, you can ask: "did this PR drop coverage below 80%?" and get a yes/no answer.

dev-coverage makes that question programmable, not interactive.

Quick start

[dependencies]
dev-coverage = "0.9"

use dev_coverage::{CoverageRun, CoverageThreshold};

let run = CoverageRun::new("my-crate", "0.1.0");
let result = run.execute()?;

let threshold = CoverageThreshold::min_line_pct(80.0);
let check = result.into_check_result(threshold);
// check is a dev_report::CheckResult ready to push into a Report.
# Ok::<(), dev_coverage::CoverageError>(())

Requirements

cargo-llvm-cov must be installed on the system:

cargo install cargo-llvm-cov

This is the only required external tool. The crate itself has no dependencies beyond dev-report.

Threshold types

Threshold	What it measures
`CoverageThreshold::MinLinePct`	Percent of executable lines exercised by tests.
`CoverageThreshold::MinFunctionPct`	Percent of functions called by at least one test.
`CoverageThreshold::MinRegionPct`	Percent of basic blocks (branch points) exercised.

Line coverage is the most common; region coverage is the most strict.

The `dev-*` suite

See dev-tools for the full suite.

Status

v0.9.0 is the foundation release: API shape is defined, the cargo-llvm-cov integration lands in 0.9.1. Production use is discouraged until 1.0.

Minimum supported Rust version

1.85 — pinned in Cargo.toml and verified by CI.

License

Apache-2.0. See LICENSE.