Fix invocation of JSON Schema library and probability check bug

FeatureFlags.psm1

@@ -35,22 +35,41 @@ Write-Verbose "Found JSON.Net assembly at $jsonLibPath"
 try {
     $jsonType = Add-Type -Path $jsonLibPath -PassThru
     $jsonSchemaType = Add-Type -Path $schemaLibPath -PassThru
-    Write-Verbose "JSON.Net type: $jsonType"
-    Write-Verbose "NjsonSchema type: $jsonSchemaType"
+    #Write-Verbose "JSON.Net type: $jsonType"
+    #Write-Verbose "NjsonSchema type: $jsonSchemaType"
 } catch {
     Write-Error "Error loading JSON libraries ($jsonLibPath, $schemaLibPath): $($_.Exception.Message)"
+    throw
 }
 
 $script:schema = $null
 try {
+    Write-Verbose "Reading JSON schema..."
     $script:schemaPath = Get-Content $PSScriptRoot\featureflags.schema.json
-    $script:schema = [NJsonSchema.JSonSchema4]::FromJsonAsync($script:schemaPath).GetAwaiter().GetResult()
-    Write-Debug "Loaded JSON schema from featureflags.schema.json."
 } catch {
-    Write-Error "Error loading JSON schema"
-    Write-Host $_.Exception.Message
+    Write-Error "Error reading JSON schema: $($_.Exception.Message)"
+    throw
 }
 
+try {
+    Write-Verbose "Loading JSON schema..."
+    $script:schema = [NJsonSchema.JSonSchema]::FromJsonAsync($script:schemaPath).GetAwaiter().GetResult()
+} catch {
+    $firstException = $_.Exception
+    # As a fallback, try reading using the JsonSchema4 object. The JSON schema library
+    # exposes that object to .NET Framework instead of JsonSchema for some reason.
+    try {
+        Write-Verbose "Loading JSON schema (fallback)..."
+        $script:schema = [NJsonSchema.JSonSchema4]::FromJsonAsync($script:schemaPath).GetAwaiter().GetResult()
+    } catch {
+        Write-Error "Error loading JSON schema: $($_.Exception.Message). First error: $($firstException.Message)."
+        Write-Host $_.Exception.Message
+        throw
+    }
+}
+Write-Verbose "Loaded JSON schema from featureflags.schema.json."
+Write-Verbose $script:schema
+
 <#
 .SYNOPSIS 
 Validates feature flag configuration.
@@ -225,9 +244,9 @@ function Test-FeatureConditions
             $probability = $condition.probability
             $random = (Get-Random) % 100 / 100.0
             Write-Verbose "random: ${random}. Checking against ${probability}"
-            if($random -gt $condition.probability)
+            if($random -ge $condition.probability)
             {
-                Write-Verbose "Probability condition not met: ${random} > ${probability}"
+                Write-Verbose "Probability condition not met: ${random} ≥ ${probability}"
                 return $false
             }
         } else {

azure-pipelines.yml

@@ -15,7 +15,7 @@ jobs:
       linux:
         imageName: 'ubuntu-16.04'
       mac:
-        imageName: 'macos-10.13'
+        imageName: 'macos-10.15'
       windows:
         imageName: 'vs2017-win2016'
 

test/FeatureFlags.Tests.ps1

@@ -4,11 +4,19 @@
            https://github.com/pester/Pester/wiki/Installation-and-Update.
            After updating, run the Invoke-Pester cmdlet from the project directory.
 #>
-
 $ModuleName = "FeatureFlags"
-Import-Module $PSScriptRoot\..\${ModuleName}.psd1 -Force
+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
+
 Describe 'Confirm-FeatureFlagConfig' {
     Context 'Validation of invalid configuration' {
         It 'Fails on empty or null configuration' {

tools/run-tests.ps1

@@ -2,11 +2,18 @@
 $parentDir = Split-Path -Parent (Split-Path -Parent $PSCommandPath)
 $testDir = Join-Path $parentDir -ChildPath "test"
 
+# Debug info.
+$PSVersionTable | Out-String
+
+Write-Host "Checking for Pester > 4.0.0..."
 $pester = Get-Module -ListAvailable | Where-Object {$_.Name -eq "Pester" -and $_.Version -gt '4.0.0'}
 if ($pester.Count -eq 0) {
     Write-Host "Cannot find the Pester module. Installing it."
-    Install-Module Pester -Force -Scope CurrentUser
+    Install-Module Pester -Force -Scope CurrentUser -RequiredVersion 4.10.1
+} else {
+    Write-Host "Found Pester version $($pester.Version)."
 }
+
 $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."