cargo-llvm-cov vs EclEmma

cargo-llvm-cov is a Cargo subcommand that uses rustc’s LLVM source-based instrumentation to generate code coverage reports. It works with cargo test, cargo run, and cargo nextest through a Cargo-compatible command-line interface, and supports proc-macro UI tests. Line and region coverage are available; branch coverage is optional and requires nightly Rust. Doc-test coverage is also optional and requires nightly features. Reports can be generated as text, HTML, JSON, LCOV, Cobertura XML, or Codecov Custom Coverage format. The project provides GitHub Actions examples for uploading reports to Codecov and a GitLab CI example using Cobertura output. LCOV results can be viewed in VS Code with the Coverage Gutters extension. With compatible Clang and LLVM tools configured, the tool can include C and C++ code linked to a Rust library or binary. It supports Linux, macOS, and Windows, and is licensed under either Apache-2.0 or MIT at the user's choice. Installation requires rustc 1.87 or newer, while running it requires Cargo 1.60 or newer. Branch and doc-test coverage are unstable and have known issues, respectively.

EclEmma is a Java code coverage tool that brings coverage analysis into the Eclipse workbench. It supports local Java applications, Eclipse and RCP applications, Equinox OSGi, JUnit, TestNG, Eclipse plug-in and RAP tests, SWTBot tests, and Scala applications. Its Coverage view summarizes results by project and lets developers inspect methods; source editors highlight covered and uncovered code. Coverage summaries can use instruction, branch, line, method, type and cyclomatic complexity counters. Users can switch among coverage sessions or merge results from separate test runs. EclEmma imports JaCoCo.exec data and exports reports in HTML, XML or CSV, as well as JaCoCo execution data files. It is based on JaCoCo and can be installed through the Eclipse Marketplace Client, an update site or manually. The free plug-in is listed at free under the Eclipse Public License 2.0. It requires Eclipse 3.8 or higher, Java 1.5 or higher, and Eclipse Java development tools; the project states that it has no operating-system dependency. Its Eclipse integration focuses on individual developers, with JaCoCo integrations suggested for automated builds.