scalac-scoverage-plugin

# scalac-scoverage-plugin

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scoverage is a free Apache licensed code coverage tool for Scala that offers
statement and branch coverage.  scoverage is available for
[sbt](https://github.com/scoverage/sbt-scoverage),
[Maven](https://github.com/scoverage/scoverage-maven-plugin),
[Mill](https://com-lihaoyi.github.io/mill/mill/Plugin_Scoverage.html), and
[Gradle](https://github.com/scoverage/gradle-scoverage).


**NOTE**: That this repository contains the Scala compiler plugin for Code coverage
in Scala 2 and other coverage utilities for generating reports. For Scala 3 code
coverage the [compiler](https://github.com/lampepfl/dotty) natively [produces](https://nightly.scala-lang.org/docs/internals/coverage.html)
code coverage output, but the reporting logic utilities are then shared with the
Scala 2 code coverage utilities in this repo.

![Screenshot of scoverage report html](misc/screenshot2.png)

### Statement Coverage

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 one
statement per line, and more usually have one statement spread across multiple lines.

In powerful, expressive languages like Scala, quite often multiple statements, or even branches
are 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 coverage
yet you only have 50% statement coverage.

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

```
val status = if (Color == Red) Stop els