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Pester

Basic Setup​

Solution​

function Add-Numbers($a, $b) {
    return $a + $b
}
function Add-Numbers($a, $b) {
    return $a + $b
}

Tests​

BeforeAll {
    . $PSCommandPath.Replace(".Tests.ps1", ".ps1")
}

Describe "Add-Numbers" {
    It "adds positive numbers" {
        Add-Numbers 1 1 | Should -Be 2
    }
    It "adds negative numbers" {
        Add-Numbers 1 -6 | Should -Be -5
    }
}
BeforeAll {
    . $PSCommandPath.Replace(".Tests.ps1", ".ps1")
}

Describe "Add-Numbers" {
    It "adds positive numbers" {
        Add-Numbers 1 1 | Should -Be 2
    }
    It "adds negative numbers" {
        Add-Numbers 1 -6 | Should -Be -5
    }
}

Improving Logging​

Because Pester doesn't provide a way to log extra information (and outputting from the solution interferes with the actual returned value), debugging on Codewars can be difficult. Write-Host somewhat works by bypassing Pester. But all of the logs will be shown at the top and not inside each test cases like many of the other languages.

Tests like the following can help minimize the frustration:

Describe "Multiply" {
  Context "Fixed Tests" {
    # Parameterized test
    It "Multiply <a> <b> is <p>" -TestCases @(
      @{ a = 2; b = 2; p = 4 }
      @{ a = 1; b = 1; p = 1 }
      @{ a = 2; b = 3; p = 6 }
      @{ a = 3; b = 2; p = 6 }
    ) {
      param ($a, $b, $p)
      Multiply $a $b | Should Be $p
    } 
  }
  Context "Random Tests" {
    # try to generate useful test case names because
    # inspecting the arguments is difficult
    $rand = New-Object System.Random
    For ($i=0; $i -lt 100; $i++) {
      $a = $rand.next(1, 100)
      $b = $rand.next(1, 100)
      $p = $a * $b
      It("Multiply $($a) $($b) is $($p)") {
        Multiply $a $b | Should Be $p
      }
    }
  }
}
Describe "Multiply" {
  Context "Fixed Tests" {
    # Parameterized test
    It "Multiply <a> <b> is <p>" -TestCases @(
      @{ a = 2; b = 2; p = 4 }
      @{ a = 1; b = 1; p = 1 }
      @{ a = 2; b = 3; p = 6 }
      @{ a = 3; b = 2; p = 6 }
    ) {
      param ($a, $b, $p)
      Multiply $a $b | Should Be $p
    } 
  }
  Context "Random Tests" {
    # try to generate useful test case names because
    # inspecting the arguments is difficult
    $rand = New-Object System.Random
    For ($i=0; $i -lt 100; $i++) {
      $a = $rand.next(1, 100)
      $b = $rand.next(1, 100)
      $p = $a * $b
      It("Multiply $($a) $($b) is $($p)") {
        Multiply $a $b | Should Be $p
      }
    }
  }
}