Backward compatibility for validating JSON files using Test-JSON command

[TinaMor]

PR Description

Background

The Test-Json cmdlet was introduced in PowerShell 6.1 as a native way to validate JSON content. However, this command does not exist in Windows PowerShell 5.1 or earlier, which leads to runtime failures when scripts rely on it.

During the BuildKit installation process, attempts to use Test-Json in older environments result in the following error:

Get-Command : The term 'Test-Json' is not recognized as the name of a cmdlet, function, script file, or operable
program. Check the spelling of the name, or if a path was included, verify that the path is correct and try again.
At line:1 char:1
+ Get-Command Test-Json
+ ~~~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : ObjectNotFound: (Test-Json:String) [Get-Command], CommandNotFoundException
    + FullyQualifiedErrorId : CommandNotFoundException,Microsoft.PowerShell.Commands.GetCommandCommand

Fix

This PR remedies this by skipping JSON validation, with a warning, if the Test-JSON command does not exist.

Relevant Links

• Differences between Windows PowerShell 5.1 and PowerShell 7.x
• Test-JSON

Checklist

As part of our commitment to engineering excellence, before submitting this PR, please ensure:

• You have tested this code in both Desktop and Server environments, as well as AMD64 and ARM64 environments (functional testing).
• You have added unit tests for new code.
• You have added or updated documentation in the cmdlet docs, command-reference.md, and the modules help files.
• You have reviewed the PR/code best practices defined in the CONTRIBUTING.md.

In addition, after this PR has been reviewed, please ensure:

• If you make changes while addressing review comments, you test the final version again in both AMD64 and ARM64 environments.
• You validate that your changes have not introduced any regressions.

[Copilot]

Pull Request Overview

This PR adds backward compatibility for JSON validation by skipping the Test-Json call on Windows PowerShell 5.1 (with a warning), refines error handling, and updates supported hash algorithms.

• Limit supported checksum hash functions to SHA256, SHA384, and SHA512
• In ValidateJSONChecksumFile, warn and exit early if Test-Json is missing, and unify error messaging
• Add Pester tests for the skip logic and update documentation with a compatibility note

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
containers-toolkit/Private/CommonToolUtilities.psm1	Remove legacy hash algorithms, enforce failure on invalid JSON, skip validation when Test-Json is missing
Tests/CommonToolUtilities.Tests.ps1	Add test for skipping JSON validation, fix error message expectations
README.md	Add a note about module compatibility with PowerShell versions

Comments suppressed due to low confidence (3)

README.md:35

• [nitpick] The note suggests PowerShell 5.1 is unsupported, but you've added runtime compatibility for PS 5.1 in this PR. Consider clarifying that JSON validation is skipped on PS 5.1 but core functionality still works.

> NOTE: While this module is developed and tested with PowerShell 7, it may work with PowerShell 5.1, but it is not guaranteed. PowerShell 7 is recommended for the best experience.

Tests/CommonToolUtilities.Tests.ps1:537

• [nitpick] This test checks that no exception is thrown and that Test-Json isn’t invoked, but it doesn’t assert that the warning is emitted. Consider adding a check for the expected warning output to fully cover the new path.

It "should skip JSON validation when Test-Json is not available" {

Tests/CommonToolUtilities.Tests.ps1:538

• There's no space between the mock script block and -ParameterFilter, which will break Pester parsing. Add a space before -ParameterFilter.

Mock Get-Command -ModuleName "CommonToolUtilities" -MockWith { return $null }-ParameterFilter {