_ZIO Test_ is a featherweight testing library for effectful programs.
_ZIO Test_ is a featherweight testing library for effectful programs.
The library imagines every spec as an ordinary immutable value, providing tremendous potential for composition. Thanks to tight integration with ZIO, specs can use resources (including those requiring disposal), have well- defined linear and parallel semantics, and can benefit from a host of ZIO combinators.
import zio.test._ import zio.clock.nanoTime import Assertion.isGreaterThan object MyTest extends DefaultRunnableSpec { def spec = suite("clock")( testM("time is non-zero") { assertM(nanoTime)(isGreaterThan(0)) } ) }
The environment package contains testable versions of all the standard ZIO
environment types through the TestClock, TestConsole,
TestSystem, and TestRandom modules.
The environment package contains testable versions of all the standard ZIO
environment types through the TestClock, TestConsole,
TestSystem, and TestRandom modules. See the documentation on the
individual modules for more detail about using each of them.
If you are using ZIO Test and extending RunnableSpec a
TestEnvironment containing all of them will be automatically provided to
each of your tests. Otherwise, the easiest way to use the test implementations
in ZIO Test is by providing the TestEnvironment to your program.
import zio.test.environment._
myProgram.provideLayer(testEnvironment)Then all environmental effects, such as printing to the console or
generating random numbers, will be implemented by the TestEnvironment and
will be fully testable. When you do need to access the "live" environment,
for example to print debugging information to the console, just use the
live combinator along with the effect as your normally would.
If you are only interested in one of the test implementations for your
application, you can also access them a la carte through the make method
on each module. Each test module requires some data on initialization.
Default data is included for each as DefaultData.
import zio.test.environment._
myProgram.provideM(TestConsole.make(TestConsole.DefaultData))Finally, you can create a Test object that implements the test interface
directly using the makeTest method. This can be useful when you want to
access some testing functionality without using the environment type.
import zio.test.environment._ for { testRandom <- TestRandom.makeTest(TestRandom.DefaultData) n <- testRandom.nextInt } yield n
This can also be useful when you are creating a more complex environment to provide the implementation for test services that you mix in.