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scoverage is a free Apache licensed code coverage tool for Scala that offersstatement and branch coverage. scoverage is available forsbt,Maven,Mill, andGradle.

NOTE: That this repository contains the Scala compiler plugin for Code coveragein Scala 2 and other coverage utilities for generating reports. For Scala 3 codecoverage thecompiler natively producescode coverage output, but the reporting logic utilities are then shared with theScala 2 code coverage utilities in this repo.

In traditional code coverage tools, line coverage has been the main metric.This is fine for languages such as Java which are very verbose and very rarely have more than onestatement per line, and more usually have one statement spread across multiple lines.

In powerful, expressive languages like Scala, quite often multiple statements, or even branchesare included on a single line, eg a very simple example:

val status = if (Color == Red) Stop else Go

If you had a unit test that ran through the Color Red you would get 100% line coverageyet you only have 50% statement coverage.

Let's expand this example out to be multifaceted, albeit somewhat contrived:

val status = if (Color == Red) Stop else if (Sign == Stop) Stop else Go

Now we would get 100% code coverage for passing in the values (Green, SpeedLimit).

That's why in scoverage we focus on statement coverage, and don't even include line coverage as a metric.This is a paradigm shift that we hope will take hold.

Branch coverage is very useful to ensure all code paths are covered. Scoverage produces branch coverage metricsas a percentage of the total branches. Symbols that are deemed as branch statements are:

• If / else statements
• Match statements
• Partial function cases
• Try / catch / finally clauses

In this screenshot you can see the coverage HTML report that shows one branch of the if statement was notexecuted during the test run. In addition two of the cases in the partial function were not executed.

This project is the base library for instrumenting code via a scalac compiler plugin. To use scoverage in yourproject you will need to use one of the build plugins:

• scoverage-maven-plugin
• sbt-scoverage
• gradle-scoverage
• sbt-coveralls
• mill-contrib-scoverage
• Upload report toCodecov:Example Scala Repository
• Upload report toCodacy:Documentation

Scoverage support is available for the following tools:

• Sonar
• Jenkins

If you want to write a tool that uses this code coverage library then it is available on maven central.Search for scalac-scoverage-plugin.

You can exclude whole classes or packages by name. Pass a semicolon separatedlist of regexes to theexcludedPackages option.

For example:

-P:scoverage:excludedPackages:.*\.utils\..*;.*\.SomeClass;org\.apache\..*

The regular expressions are matched against the fully qualified class name, and must match the entire string to take effect.

Any matched classes will not be instrumented or included in the coverage report.

You can also exclude files from being considered for instrumentation.

-P:scoverage:excludedFiles:.*\/two\/GoodCoverage;.*\/three\/.*

Note: The.scala file extension needs to be omitted from the filename, if one is given.

Note: These two options only work for Scala2. Right now Scala3 does not supporta way to exclude packages or files from being instrumented.

You can also mark sections of code with comments like:

// $COVERAGE-OFF$...// $COVERAGE-ON$

Any code between two such comments will not be instrumented or included in the coverage report.

Further details are given in the plugin readme's.

For a full release history please see thereleasespage.