fix: pin Pester to 4.10.1 for compatibility with pwsh 6.0.4 (#44)

* fix: pin Pester to 4.10.1

This makes tests work under PowerShell 6.0.4.

Also, import the FeatureFlags module first in run-tests.ps1, so that any failures in importing the module are detected early.

* fix: remove BeforeAll/AfterAll

They don't seem to work well with Pester 4.10.1.

test/FeatureFlags.Tests.ps1

@@ -1,23 +1,14 @@
-<#
-    .SYNOPSIS Tests for the FeatureFlags module.
-    .NOTES Please update to the last version of Pester before running the tests:
-           https://github.com/pester/Pester/wiki/Installation-and-Update.
-           After updating, run the Invoke-Pester cmdlet from the project directory.
-#>
-BeforeAll {
-    $ModuleName = "FeatureFlags"
-    Get-Module $ModuleName | Remove-Module -Force
-    Import-Module $PSScriptRoot\test-functions.psm1
-
-    $VerbosePreference = "Continue"
-    $Module = Import-Module $PSScriptRoot\..\${ModuleName}.psd1 -Force -PassThru
-    if ($null -eq $Module) {
-        Write-Error "Could not import $ModuleName"
-        exit 1
-    }
-    Write-Host "Done."
-    Write-Host $Module.ExportedCommands.Values.Name
+$ModuleName = "FeatureFlags"
+Get-Module $ModuleName | Remove-Module -Force
+Import-Module $PSScriptRoot\test-functions.psm1
+
+$VerbosePreference = "Continue"
+$Module = Import-Module $PSScriptRoot\..\${ModuleName}.psd1 -Force -PassThru
+if ($null -eq $Module) {
+    Write-Error "Could not import $ModuleName"
+    exit 1
 }
+Write-Host "Done."
 
 Describe 'Confirm-FeatureFlagConfig' {
     Context 'Validation of invalid configuration' {
@@ -645,7 +636,5 @@ Describe 'Out-EvaluatedFeaturesFiles' -Tag Features {
     }
 }
 
-AfterAll {
-    Remove-Module $ModuleName
-    Remove-Module test-functions
-}
+Remove-Module $ModuleName
+Remove-Module test-functions

tools/run-tests.ps1

@@ -1,29 +1,45 @@
 # Fail on the first error.
 $ErrorActionPreference = "Stop"
 
-$parentDir = Split-Path -Parent (Split-Path -Parent $PSCommandPath)
-$testDir = Join-Path $parentDir -ChildPath "test"
-
 # Debug info.
 Write-Host "PowerShell version" $PSVersionTable.PSVersion
 
-$RequiredPesterVersion = "5.3.3"
+# As a first step, try to import the FeatureFlags module.
+# When loaded, the module will try to read the schema and validate it, so some
+# errors can be triggered even before loading Pester.
+$ModuleName = "FeatureFlags"
+Get-Module $ModuleName | Remove-Module -Force
+$Module = Import-Module $PSScriptRoot\..\${ModuleName}.psd1 -Force -PassThru
+if ($null -eq $Module) {
+   Write-Error "Could not import $ModuleName"
+   exit 1
+}
+Write-Host "FeatureFlags module loads successfully. Removing it."
+Get-Module $ModuleName | Remove-Module -Force
+
+# Install the required Pester version.
+# We use the latest 4.x because 5.x fails to load under PowerShell 6.0.4,
+# which is one of the versions we want to test.
+$RequiredPesterVersion = "4.10.1"
 $pesterVersions = Get-Module -ListAvailable | Where-Object {$_.Name -eq "Pester" -and $_.Version -eq $RequiredPesterVersion}
 $InstallPester = $false
 if ($pesterVersions.Count -eq 0) {
    Write-Warning "Pester $RequiredPesterVersion not found, installing it."
    $InstallPester = $true
 }
-
 if ($InstallPester) {
    Install-Module Pester -Force -Scope CurrentUser -RequiredVersion $RequiredPesterVersion -SkipPublisherCheck
 }
 
+# Load the required Pester module.
 Get-Module -Name Pester | Remove-Module
 Import-Module Pester -RequiredVersion $RequiredPesterVersion
 
+# Invoke Pester.
+$parentDir = Split-Path -Parent (Split-Path -Parent $PSCommandPath)
+$testDir = Join-Path $parentDir -ChildPath "test"
 $FailedTests = Invoke-Pester $testDir -EnableExit -OutputFile "test/results.xml" -OutputFormat "NUnitXML" -CodeCoverage "$parentDir/FeatureFlags.psm1"
 if ($FailedTests -gt 0) {
     Write-Error "Error: $FailedTests Pester tests failed."
     exit $FailedTests
-}
+}