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Scala (WarpScript)

WarpScript

WarpScript is an experimental measurement API based on the Free Monad, allowing users to represent a measurement plan as a monadic pipeline of exec and measure operations. exec is a simple wrapper around a call-by-name parameter, useful for side effects or setup test data. measure is for measuring a call-by-name parameter.

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import com.workday.warp.junit.WarpJUnitSpec
import com.workday.warp.monadic.WarpAlgebra._
import com.workday.warp.logger.WarpLogging
import org.junit.jupiter.api.Test

class WarpScriptSpec extends WarpJUnitSpec with WarpLogging {

  @Test
  def measureSpec(): Unit = {
      val demo: WarpScript[Int] = for {
        // exec() is useful for setup test data
        a <- exec(1 + 1)
        // measure() accepts a name and an expression, and measures that expression
        b <- measure("com.workday.warp.MeasureSpec.a", { logger.info("computing a"); a + 1 })
        c <- measure("com.workday.warp.MeasureSpec.b", a + b)
      } yield c

      // run the script
      interpretImpure(demo) should be (5)
  }
}

Macros

In our own testing, we found it cumbersome to repeat variables and TestIds within a WarpScript, so we provide a macro that will rewrite a WarpScript and automatically derive a TestId for each measured section within the script. For example, a script such as this:

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for {
  a <- exec(1 + 1)
  b <- measure(a + 1)
  c <- measure(b + 1)
  d <- measure(c + 1)
} yield d

will be macro-expanded into this (assuming it is defined within a class called com.workday.warp.MacroExampleSpec):

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for {
  a <- exec(1 + 1)
  b <- measure("com.workday.warp.MacroExampleSpec.b", a + 1)
  c <- measure("com.workday.warp.MacroExampleSpec.c", b + 1)
  d <- measure("com.workday.warp.MacroExampleSpec.d", c + 1)
} yield d

Note the match between the bound variable and the TestId on each line. We found it difficult to implement a macro that appropriately targets minor AST differences across different scala versions, so we publish macros as a separate artifact com.workday.warp:warp-core-macros_2.13 that only targets scala 2.13.

Here is a more complete example:

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import com.workday.warp.monadic.WarpAlgebra._
import com.workday.warp.monadic.WarpMacros.deriveTestIds
import org.junit.jupiter.api.Test

class MacroExampleSpec {

  @Test
  def macroExample(): Unit = {
    val script: WarpScript[Option[String]] = deriveTestIds {
      for {
        a <- exec(1 + 1)
        b <- measure(a.toString + "abcd")
        c <- measure("defg" :: List(b))
        d <- measure(c.headOption)
      } yield d
    }

    interpretImpure(script)
  }
}