Switch Windows CI virtual displays from usbmmidd_v2 to VirtualDrivers/Virtual-Display-Driver

[Copilot]

SetCurrentTopology_DuplicatedTopology fails because usbmmidd_v2 creates displays with DISPLAYCONFIG_OUTPUT_TECHNOLOGY_OTHER, which Windows refuses to use in clone/duplicate topology operations on modern runners.

Test changes

• DuplicatedTopology and MixedTopology system tests now use getAvailableDevices(*m_layer) (default only_valid_output=true) instead of false, filtering out DISPLAYCONFIG_OUTPUT_TECHNOLOGY_OTHER displays — consistent with how the equivalent mode tests already behave, and enables graceful skip rather than hard fail when no clonable displays are present

CI changes

Replace usbmmidd_v2 with VirtualDrivers/Virtual-Display-Driver (VDD 25.7.23), an officially signed IDD-based driver whose displays:

• Report a proper output technology (not OTHER), so they pass the only_valid_output=true filter
• Support all topology modes including clone/duplicate

Installation steps added to the Prepare tests step:

• Download NefCon v1.17.40 for command-line UMDF driver installation
• Extract VDD signing certs from mttvdd.cat → install into TrustedPublisher store
• Pre-create C:\VirtualDisplayDriver\vdd_settings.xml with <count>2</count> before driver load (driver reads this on startup to determine monitor count)
• Install via nefconw.exe install MttVDD.inf "Root\MttVDD"
• Poll Get-PnpDevice -HardwareID "Root\MttVDD" for OK status (up to 60 s) instead of a hardcoded sleep

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• https://api.github.com/repos/VirtualDrivers/Virtual-Display-Driver/contents/VirtualDisplayDriver
  • Triggering command: /home/REDACTED/work/_temp/ghcca-node/node/bin/node /home/REDACTED/work/_temp/ghcca-node/node/bin/node --enable-source-maps /home/REDACTED/work/_temp/copilot-developer-action-main/dist/index.js (http block)
• https://api.github.com/repos/VirtualDrivers/Virtual-Display-Driver/git/trees/master
  • Triggering command: /home/REDACTED/work/_temp/ghcca-node/node/bin/node /home/REDACTED/work/_temp/ghcca-node/node/bin/node --enable-source-maps /home/REDACTED/work/_temp/copilot-developer-action-main/dist/index.js (http block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>2 Unit tests failing on Windows in CI</issue_title>
<issue_description>### Describe the Bug

Two unit tests are consistently failing on Windows in GitHub CI/CD.

https://github.com/LizardByte/libdisplaydevice/actions/runs/23116234792/job/67142327315

[  FAILED  ] 2 tests, listed below:
[  FAILED  ] WinDisplayDeviceTopology.SetCurrentTopology_DuplicatedTopology
[  FAILED  ] WinDisplayDeviceTopology.SetCurrentTopology_MixedTopology

Expected Behavior

Tests should pass.

Additional Context

No response</issue_description>

<agent_instructions>Find the cause of the failing tests and a proper fix. If the failing tests indicate a problem with the actual source code, then the fix should be in the source code. If the failing tests indicate a problem with flaky tests, then the fix should be either in the test code or in the CI/CD setup/prep.</agent_instructions>

Comments on the Issue (you are @copilot in this section)

• Fixes 2 Unit tests failing on Windows in CI #217

---

🔒 GitHub Advanced Security automatically protects Copilot coding agent pull requests. You can protect all pull requests by enabling Advanced Security for your repositories. Learn more about Advanced Security.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 93.12%. Comparing base (c8f4bdc) to head (2c4ed9b).
✅ All tests successful. No failed tests found.

Additional details and impacted files

@@           Coverage Diff           @@
##           master     #218   +/-   ##
=======================================
  Coverage   93.12%   93.12%           
=======================================
  Files          34       34           
  Lines        2123     2123           
  Branches     1086     1086           
=======================================
  Hits         1977     1977           
  Misses         82       82           
  Partials       64       64           

Flag	Coverage Δ
Linux	93.73% <ø> (ø)
Windows	92.80% <ø> (ø)
macOS	74.20% <ø> (ø)

Flags with carried forward coverage won't be shown. Click here to find out more.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud