Make the CI pipeline work with Pester 5 and later

[Mike-Crowley]

Fixes #1744

Problem

Every Azure Pipelines job currently fails on every PR — including trivial ones — before running a single test. All six jobs (e.g. on #1721, #1723, #1729, #1741, #1742) stop in the "Install and Test" step with:

Invoke-Pester : A parameter cannot be found that matches parameter name 'OutputFile'.
At D:\a\1\s\CI\CI.ps1:113 char:34

The pipeline's "Update Pester" step installs the latest Pester (currently 6.x) on every agent, but CI/CI.ps1 still uses the Pester 4 invocation syntax: -OutputFile was removed in Pester 5, and the result object's TestResult property became Tests/Failed.

Changes

CI/CI.ps1 — when New-PesterConfiguration exists (Pester 5+), build a configuration object instead: TestResult.Enabled + OutputPath produce the same TestResultsPS<version>.xml NUnit file the PublishTestResults task consumes (the default output format is NUnit 2.5, matching the task's testResultsFormat: 'NUnit'), and Filter.Tag/Filter.ExcludeTag reproduce the TestImportOnly handling. Failed tests are listed from the v5 Failed collection. On older Pester the original code runs unchanged.

Five tests — with the invocation fixed, five tests still fail under Pester 5+ because Set-ItResult -Pending no longer exists (Parameter set cannot be resolved...). These are all placeholders for known EPPlus 4.5 bugs (plus one "can't test passwords on PS6+" guard); they now use -Skipped, which Pester 4.7+ and 5+ both support:

• Export-Excel.Tests.ps1, ExtraLongCmd.tests.ps1, First10Races.tests.ps1, Join-Worksheet.tests.ps1 ("Bug in EPPLus 4.5")
• PasswordProtection.tests.ps1 ("Can't test passwords on V6 and later")

Compare-WorkSheet.tests.ps1 — the Windows PowerShell GridView test spawns a child powershell.exe -Command $cmdline; native argument passing mangles the embedded quotes, so the child's Import-Module fails whenever the repository path contains spaces and the test fails with Expected 'FF90EE90', but got $null. CI agents (D:\a\1\s) never see this, but local contributors with spaces in their clone path do. The child is now launched with -EncodedCommand, which sidesteps quoting entirely.

Verification

Ran ./CI/CI.ps1 -Test end to end (including CI/Install.ps1, against a sandboxed PSModulePath) with Pester 6.0.1:

	Result
PowerShell 7.6	277 passed, 0 failed, 7 skipped
Windows PowerShell 5.1	287 total, 0 failures (NUnit XML)
./CI/CI.ps1 -TestImportOnly	tag filter selects exactly the 1 import test

Also verified the failure branch behaves (a failing test produces the "Test failures:" listing and a non-zero exit), and that the produced TestResultsPS*.xml is valid NUnit 2.5 with one test-case per test.

This should let the pipeline actually validate the open PRs again.

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Updates the repository’s CI test runner and a handful of tests to be compatible with Pester 5+ (while keeping a Pester 4 fallback), unblocking Azure Pipelines from failing before tests execute.

Changes:

• Updated CI/CI.ps1 to use New-PesterConfiguration / Invoke-Pester -Configuration when available (Pester 5+), retaining the legacy Pester 4 invocation otherwise.
• Replaced Set-ItResult -Pending with Set-ItResult -Skipped in five placeholder/guard tests to avoid Pester 5+ parameter-set failures.
• Fixed Windows PowerShell child process invocation in Compare-WorkSheet.tests.ps1 by switching to -EncodedCommand to avoid quote-mangling when paths contain spaces.

Reviewed changes

Copilot reviewed 7 out of 7 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
CI/CI.ps1	Switches CI Pester invocation to configuration-object mode for Pester 5+ while preserving Pester 4 behavior.
tests/PasswordProtection.tests.ps1	Updates placeholder test outcome from Pending to Skipped for Pester 5+ compatibility.
tests/Join-Worksheet.tests.ps1	Updates placeholder test outcome from Pending to Skipped for Pester 5+ compatibility.
tests/First10Races.tests.ps1	Updates placeholder test outcome from Pending to Skipped for Pester 5+ compatibility.
tests/ExtraLongCmd.tests.ps1	Updates placeholder test outcome from Pending to Skipped for Pester 5+ compatibility.
tests/Export-Excel.Tests.ps1	Updates placeholder test outcome from Pending to Skipped for Pester 5+ compatibility.
tests/Compare-WorkSheet.tests.ps1	Uses powershell.exe -EncodedCommand to make module import robust when repo paths contain spaces.

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