1. Docker image for running unit tests 
   1. gives engineers a consistent way to run the unit tests. One your workstation you might need different versions of SDKs and tools, but a docker container lets you pin versions of things like the AWS Powershell tools
   2. Makes all pathing consistent – you can setup your laptop anyway you lock, but the paths inside of the container are consistent
2. Docker-compose
   1. Provides a way to customize unit test runs to a project
   2. Provides a consistent way for engineers to map drives into the container
3. Code coverage metrics
   1. At my company we don’t put too much stock in code coverage metrics, but they offer some context for how thorough an engineer has been with unit tests
   2. We keep a loose goal of 60%
4. Unit test passing count
   1. A failed unit test does not go to production. A failed unit test has a high chance of causing production outage

How!

• /
  • docker-compose.yml
  • /pestertester
    • Dockerfile
    • Run-AllUnitTests.ps1

We call our image “pestertester” (I’m more proud of that name than I should be).

• /ConfigModule.psm1
  • /tests
    • /ConfigModule.tests.ps1
• ConfigModule2.psm1
  • /tests
    • /ConfigModule2.tests.ps1

$results = @();
gci -recurse -include tests -directory | ? {$_.FullName -notlike "*dsc*"} | % {
    set-location $_.FullName;
    $tests = gci;
    foreach ($test in $tests) {
        $module = $test.Name.Replace("tests.ps1","psm1")
        $result = invoke-pester ".\$test" -CodeCoverage "..\$module" -passthru -quiet;
        $results += @{Module = $module;
                      Total = $result.TotalCount;
                      passed = $result.PassedCount;
                      failed = $result.FailedCount
                      codecoverage = [math]::round(($result.CodeCoverage.NumberOfCommandsExecuted / $result.CodeCoverage.NumberOfCommandsAnalyzed) * 100,2)
                    }
    }
}

foreach ($result in $results) {
    write-host -foregroundcolor Magenta "module: $($result['Module'])";
    write-host "Total tests: $($result['total'])";
    write-host -ForegroundColor Green "Passed tests: $($result['passed'])";
    if($result['failed'] -gt 0) {
        $color = "Red";
    } else {
        $color = "Green";
    }
    write-host -foregroundcolor $color "Failed tests: $($result['failed'])";
    if($result['codecoverage'] -gt 60) {
        $color = "Green";
    } elseif($result['codecoverage'] -gt 30) {
        $color = "Yellow";
    } else {
        $color = "Red";
    }
    write-host -ForegroundColor $color "CodeCoverage: $($result['codecoverage'])";
}

The last piece to tie all of this together is a docker-compose file. The docker compose file handles

1. Mapping the windows drives into the container
2. Executing the script that runs the unit tests

version: '3.7'

services:
  pestertester:
    build: ./pestertester
    volumes:
      - c:\users\bolson\documents\github\dt-infra-citrix-management\ssm:c:\ssm
    stdin_open: true
    tty: true
    command: powershell "cd ssm;C:\scripts\Run-AllUnitTests.ps1"