Contributing to Scala's OSS Ecosystem

Running the Test Suite


Partest is a custom parallel testing tool that we use to run the test suite for the Scala compiler and library. Go to the scala project folder from your local checkout and run it via sbt, ant or standalone as follows.

Using sbt

The test suite can be run from the sbt console with:

sbt:root> partest

You can get a summary of the usage by running partest --help.

If you would like to run particular tests pass the test paths as arguments

sbt:root> partest test/files/pos/bounds.scala test/scaladoc/run/diagrams-base.scala

To run only the Scaladoc tests use --srcpath with the location of the tests

sbt:root> partest --srcpath scaladoc

Using ant

Please note support for ant was removed on the 2.12 branch.

The test suite can be run by using ant from the command line:

$ ant test.suite


Please note the standalone scripts mentioned below were removed in 2.12.2. sbt is the preferred way to run the test suite.

There are launch scripts partest and partest.bat in the test folder of the scala project. To have partest run failing tests only and print details about test failures to the console, you can use

./test/partest --show-diff --show-log --failed

You can get a summary of the usage by running partest without arguments.

  • Most commonly you want to invoke partest with an option that tells it which part of the tests to run. For example --all, --pos, --neg or --run.
  • You can test individual files by specifying individual test files (.scala files) as options. Several files can be tested if they are from the same category, e.g., pos.
  • You can enable output of log and diff using the -show-log and -show-diff options.
  • If you get into real trouble, and want to find out what partest does, you can run it with option --verbose. This info is useful as part of bug reports.
  • Set custom path from where to load classes: -classpath <path> and -buildpath <path>.
  • You can use the SCALAC_OPTS environment variable to pass command line options to the compiler.
  • You can use the JAVA_OPTS environment variable to pass command line options to the runner (e.g., for run/jvm tests).
  • The launch scripts run partest as follows:

      scala -cp <path to partest classes> <options>

    Partest classes from a quick build, e.g., can be found in ./build/quick/classes/partest/.

    Partest will tell you where it loads compiler/library classes from by adding the partest.debug property:

      scala -Dpartest.debug=true -cp <path to partest classes> <options>

ScalaCheck tests

Tests that depend on ScalaCheck can be added under folder ./test/files/scalacheck. A sample test:

import org.scalacheck._
import Prop._

object Test {
	val prop_ConcatLists = property{ (l1: ListInt, l2: ListInt) =>
		l1.size + l2.size == (l1 ::: l2).size

	val tests = List(("prop_ConcatLists", prop_ConcatLists))



Some tests might fail because line endings in the .check files and the produced results do not match. In that case, set either

git config core.autocrlf false


git config core.autocrlf input

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