Global Configuration

Some property test settings can be set globally for all property tests.

Default Iterations

The standard default iteration count is 1000. This means when you don't specify the iteration count in a property test, the default will be 1000.

We can override this default either by assigning a value to PropertyTesting.defaultIterationCount, or by using the system property kotest.proptest.default.iteration.count.

Any test which directly sets the iteration count will of course use that value.

For example:

PropertyTesting.defaultIterationCount = 123

// will use 555 iterations specified in the test
forAll<String, String>(555) { a,b -> a + b == "$a$b" }

// will use 123 iterations from the global default
forAll<String, String> { a,b -> a + b == "$a$b" }

If you are using Kotest framework, then you can perform this action before any tests by using project config. For example:

class KotestConfig : AbstractProjectConfig() {
   override suspend fun beforeProject() {
      PropertyTesting.defaultIterationCount = 123
   }
}

Printing Shrink Steps

By default, when using shrinking, each shrinking step will not be logged, but only the final shrunk value.

To enable logging of each intermediate value, assign true to PropertyTesting.shouldPrintShrinkSteps or use the system property kotest.proptest.output.shrink-steps=true.