How do I properly use the same `withData`for multiple tests? :thread:

# kotest

[mcpiroman]

How do I properly use the same `withData`for multiple tests? 🧵

[mcpiroman]

If I do

class Foo : FunSpec({
    context("foo") {
        withData(listOf(1f, -1f, 100000f)) { n ->
            test("add")      { n + 3f    shouldBeExactly n + 1 + 1 + 1 }
            test("multiply") { n * 3f    shouldBeExactly n + n + n }
            test("power")    { n.pow(3f) shouldBeExactly n * n * n }
        }
    }
})

It works, but yields very messy output:

[sam]

What output would you prefer to see ?

[mcpiroman]

A one that is anyhow structured. May be:

1.0
• multiply
• power
-1.0
• multiply
• power
Or:

multiply
• 1.0
• -1.0
power:
• 1.0
• -1.0

[sam]

You can nest withData many times

[mcpiroman]

Yes, but it just creates product of the data. I need to provide the same set of data to different tests. In JUnit4 it would be class parametrized tests.

[mcpiroman]

For context I need to test a database like table. The table can be configured with different indices, which do not alter behavior, only performance characteristics. Thus I want to run all table tests with different index configurations.

[sam]

you could do manual for each loops then create the tests inside however you need to