DeltaCover

DeltaCover is a lightweight, open-source code coverage tool designed for Java applications. It provides developers with insights into which parts of their code are executed during testing, helping to identify untested or rarely tested code paths. The tool is particularly useful for improving test coverage and ensuring more reliable software.

DeltaCover operates by analyzing bytecode rather than source code, which allows it to work with compiled applications without requiring modifications to the source files. It integrates seamlessly with Java Virtual Machines (JVMs) and can be used alongside other testing frameworks like JUnit or TestNG. The tool generates detailed reports, including metrics such as line coverage, branch coverage, and method coverage, which help developers assess the thoroughness of their test suites.

One of the key features of DeltaCover is its ability to compare coverage results between different runs, such as comparing test coverage before and after adding new tests. This delta analysis helps developers identify improvements in test coverage and pinpoint areas where additional test cases may be needed. The tool also supports incremental coverage analysis, making it efficient for continuous integration environments.

DeltaCover is distributed under an open-source license, allowing developers to use, modify, and distribute the tool freely. It is maintained by a community of developers and is regularly updated to support new Java versions and testing frameworks. While it is not as widely known as some other coverage tools, DeltaCover is valued for its simplicity, efficiency, and flexibility in measuring and improving code coverage.