(#2854) Pester tests to Get-ChocolateyConfigValue

Add pester tests around the functionality added by
Get-ChocolateyConfigValue

tests/chocolatey-tests/features/ChocolateyFunctions.Tests.ps1

@@ -0,0 +1,39 @@
+# These tests install packages that exercise the Chocolatey PowerShell functions
+# TODO: Move some of the install tests into this file
+Describe 'Chocolatey PowerShell functions' {
+    BeforeAll {
+        Initialize-ChocolateyTestInstall
+    }
+
+    Context 'Get-ChocolateyConfigValue' -ForEach @{
+        ConfigValues = @(
+            @{ Name = 'addedTextValue' ; Value = 'SomeTextValue' }
+            @{ Name = 'addedNumberValue' ; Value = 123456 }
+            @{ Name = 'commandExecutionTimeoutSeconds' ; Value = 2795 }
+            @{ Name = 'cacheLocation' ; Value = $null }
+            @{ Name = 'nonExistentKey' ; Value = $null }
+        )
+    } -Tag Get-ChocolateyConfigValue {
+
+        BeforeAll {
+            Restore-ChocolateyInstallSnapshot
+
+            foreach ($Value in $ConfigValues) {
+                if ($null -ne $Value.Value) {
+                    Invoke-Choco config set --name $Value.Name --value $Value.Value
+                }
+            }
+
+            $Output = Invoke-Choco install getconfig --confirm
+        }
+
+        It 'Exits with Success (0)' {
+            $Output.ExitCode | Should -Be 0 -Because $Output.String
+        }
+
+        It 'Outputs the expected value for config entry (<Name>)' -ForEach $ConfigValues {
+            # Trim the output as Lines is trimmed.
+            $Output.Lines | Should -Contain "${Name}: $Value".Trim() -Because $Output.String
+        }
+    }
+}

tests/packages/getconfig/getconfig.nuspec

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+<?xml version="1.0" encoding="utf-8"?>
+<!-- Do not remove this test for UTF-8: if “Ω” doesn’t appear as greek uppercase omega letter enclosed in quotation marks, you should use an editor that supports UTF-8, not this one. -->
+<package xmlns="http://schemas.microsoft.com/packaging/2015/06/nuspec.xsd">
+  <metadata>
+    <id>getconfig</id>
+    <version>1.0.0</version>
+    <owners>Chocolatey</owners>
+    <title>getconfig</title>
+    <authors>Chocolatey</authors>
+    <copyright>Chocolatey</copyright>
+    <tags>getconfig</tags>
+    <description>Test package for using Get-ChocolateyConfigValue.</description>
+  </metadata>
+  <files>
+    <file src="tools\**" target="tools" />
+  </files>
+</package>

tests/packages/getconfig/tools/chocolateyinstall.ps1

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+$ErrorActionPreference = 'Stop'
+
+$ValuesToTest = @(
+    'addedTextValue'
+    'addedNumberValue'
+    'commandExecutionTimeoutSeconds'
+    'cacheLocation'
+    'nonExistentKey'
+)
+
+foreach ($Value in $ValuesToTest) {
+    $Result = Get-ChocolateyConfigValue -configKey $Value
+    Write-Host "${Value}: $Result"
+}