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Version: 2.0.x

Running Tests

We can run ZIO Tests in two ways:

  1. If we added zio.test.sbt.ZTestFramework to SBT's testFrameworks, our tests should be automatically picked up by SBT on invocation of test:
sbt test                      // run all tests
sbt testOnly HelloWorldSpec // run a specific test

To run a specific test by their labels, we can use the -t "<label>" option. Assume we have multiple tests like the below:

import zio.test._

object ExampleSpec extends ZIOSpecDefault {
def spec = suite("clock")(
test("foo") {
test("foo bar") {
test("foo bar baz") {

We can run those test that contains the "bar" label using the following SBT command:

testOnly ExampleSpec -- -t "bar"

You can also execute the single SBT command directly from the shell with this command that properly quotes and escapes arguments:

sbt "testOnly ExampleSpec -- -t \"bar\""

It will print the following results after running all tests containing the "bar" label:

sbt:zio-2.0> testOnly ExampleSpec -- -t "bar"
+ example suite
+ foo bar
+ foo bar baz
3 tests passed. 0 tests failed. 0 tests ignored.
  1. However, if we're not using SBT or have some other special needs, the ZIOSpecDefault has a main method which can be invoked directly or with SBTs Test/run or Test/runMain commands:
sbt Test/run                       // prompt to choose which test to run
sbt Test/runMain HelloWorldSpec // run a specific test