feat(tests):add Get-ReleaseAsset tests

ps-arch-wsl/ps-arch-wsl.Tests.ps1

@@ -0,0 +1,29 @@
+BeforeAll {
+    Import-Module $PSScriptRoot/ps-arch-wsl.psm1 -Force
+}
+
+Describe "Get-ReleaseAsset" {
+    It "Finds the release asset" {
+        InModuleScope ps-arch-wsl {
+            $foundAsset = Get-ReleaseAsset -Repository "yuk7/ArchWSL" -AssetFilter "cer"
+            $latestCertificateInTemp = Get-ChildItem $env:Temp | Where-Object { $_.FullName -like "*.cer" } | Sort-Object -Property CreationTime -Descending
+            $foundAsset | Should -Be $latestCertificateInTemp[0].FullName
+        }
+    }
+
+    It "Can't find the release asset" {
+        InModuleScope ps-arch-wsl {
+            $repository = "yuk7/ArchWSL"
+            $filter = "someNonExistentExt"
+            { Get-ReleaseAsset -Repository $repository -AssetFilter $filter } | Should -Throw -ExpectedMessage "Failed to find an asset matching the filter '$filter' from the latest release of $repository."
+        }
+    }
+
+    It "Can't find the repository" {
+        InModuleScope ps-arch-wsl {
+            $repository = "scottmckendry/norepositoryhere"
+            $filter = "doesntmatter"
+            { Get-ReleaseAsset -Repository $repository -AssetFilter $filter } | Should -Throw -ExpectedMessage "$repository doesn't exist or has no releases."
+        }
+    }
+}