🧪 [Test]: Cover parallel module sessions

Exercise concurrent runspace and process imports plus direct byte-array key derivation.

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>

Author: MariusStorhaug

tests/Sodium.Tests.ps1

@@ -163,6 +163,14 @@ Describe 'Sodium' {
             $derivedPublicKey | Should -Be $expectedPublicKey
         }
 
+        It 'Get-SodiumPublicKey - Returns the public key as a byte array' {
+            $keyPair = New-SodiumKeyPair
+            $derivedPublicKey = Get-SodiumPublicKey -PrivateKey $keyPair.PrivateKey -AsByteArray
+
+            $derivedPublicKey | Should -BeOfType ([byte])
+            [Convert]::ToBase64String($derivedPublicKey) | Should -Be $keyPair.PublicKey
+        }
+
         It 'Get-SodiumPublicKey - Throws an error when an invalid private key is provided' {
             $invalidPrivateKey = 'InvalidKey'
 
@@ -186,4 +194,46 @@ Describe 'Sodium' {
             }
         }
     }
+
+    Context 'Parallel sessions' {
+        It 'Loads and completes crypto round trips in parallel runspaces' {
+            $modulePath = (Get-Module -Name Sodium -ErrorAction Stop).Path
+            Test-Path -Path $modulePath | Should -BeTrue
+            $results = 1..4 | ForEach-Object -Parallel {
+                Import-Module -Name $using:modulePath -Force
+                $keyPair = New-SodiumKeyPair -Seed "Runspace-$_"
+                $message = "Parallel runspace $_"
+                $sealedBox = ConvertTo-SodiumSealedBox -Message $message -PublicKey $keyPair.PublicKey
+                ConvertFrom-SodiumSealedBox -SealedBox $sealedBox -PrivateKey $keyPair.PrivateKey
+            } -ThrottleLimit 4
+
+            $results | Should -HaveCount 4
+            $results | Should -Contain 'Parallel runspace 1'
+            $results | Should -Contain 'Parallel runspace 4'
+        }
+
+        It 'Loads and completes crypto round trips in parallel processes' {
+            $modulePath = (Get-Module -Name Sodium -ErrorAction Stop).Path
+            $jobs = 1..4 | ForEach-Object {
+                Start-Job -ScriptBlock {
+                    $id = $args[0]
+                    $modulePath = $args[1]
+                    Import-Module -Name $modulePath -Force
+                    $keyPair = New-SodiumKeyPair -Seed "Process-$id"
+                    $message = "Parallel process $id"
+                    $sealedBox = ConvertTo-SodiumSealedBox -Message $message -PublicKey $keyPair.PublicKey
+                    ConvertFrom-SodiumSealedBox -SealedBox $sealedBox -PrivateKey $keyPair.PrivateKey
+                } -ArgumentList $_, $modulePath
+            }
+
+            try {
+                $results = $jobs | Receive-Job -Wait
+                $results | Should -HaveCount 4
+                $results | Should -Contain 'Parallel process 1'
+                $results | Should -Contain 'Parallel process 4'
+            } finally {
+                $jobs | Remove-Job -Force
+            }
+        }
+    }
 }