Divides a test suite into groups with equal execution time, based on prior test timings.
This ensures optimal parallel execution. Since test file runtimes can vary significantly, splitting them evenly without considering timing may result in inefficient grouping.
This tool was written for Java and released as JAR archive.
Download and extract the latest build from the releases page.
Execute the test split with the required arguments. The tool returns the set of test classes for the current split, joined by spaces.
java -jar split-tests-java.jar --split-index 0 --split-total 10 --glob '**/*Test.java'For example, check out the project into project and the JUnit reports into reports.
java -jar split-tests-java.jar --split-index 0 --split-total 10 --glob 'project/**/*Test.java' --junit 'reports/**/*.xml'
Usage: <main class> [options]
Options:
* --split-index, -i
This test split index.
Default: 0
* --split-total, -t
Total number of test splits.
Default: 0
* --glob, -g
Glob pattern to find test files. Make sure to single-quote the pattern
to avoid shell expansion.
--calculate-optimal-total-split, -c
Calculates the optimal test split (only on the first split index). Logs
a warning if --split-total does not match.
Default: false
--debug, -d
Enables debug logging.
Default: false
--exclude-glob, -e
Glob pattern to exclude test files. Make sure to single-quote the
pattern to avoid shell expansion.
--format, -f
The output format.
Default: list
Possible Values: [list, gradle]
--help, -h
Prints the usage.
--junit-glob, -j
Glob pattern to find JUnit reports. Make sure to single-quote the
pattern to avoid shell expansion.
--max-optimal-total-split-calculations, -m
The maximum number of --calculate-optimal-total-split calculations.
Default: 50
--new-test-time, -n
Configures the calculation of the test time for tests without JUnit
reports.
Default: average
Possible Values: [zero, average, min, max]
--working-directory, -w
The working directory. Defaults to the current directory.
This tool is written in Java and uses Gradle as build tool.
- Install Java 21
- Checkout the repository
./gradlew shadowJar
split-tests-java is inspired by split-test for Ruby.
In comparison to split-test, split-tests-java works with standard JUnit reports without a file or filepath
attribute.
The output are also fully qualified class names instead of file names.
This makes it compatible with default Java tooling.