qemu_guest_agent: Add test for QGA install without virtio-serial

[6-dehan]

Add a new test case gagent_install_no_device to verify that 'QEMU Guest Agent (QGA)' can be successfully installed on a VM booted without a virtio-serial device.

Changes:

• cfg: Add gagent_install_no_device test variant and no_serial serial variant.
• py:
• Implement gagent_check_install_no_device using direct MSI install command.
• Update setup to skip agent creation when serial type is none.
• Update run_once to skip verification for install_no_device case.

ID: 4506
Signed-off-by: Dehan Meng [email protected]

Summary by CodeRabbit

• Tests
  • Added a Windows-specific test variant for guest-agent installation without a virtio-serial device.
  • Added a corresponding no-serial variant to cover device-less scenarios.
  • Introduced dedicated test paths that bypass serial-device checks to validate installation behavior without serial support.
  • Expanded coverage for no-serial configurations across Linux and Windows.

_{✏️ Tip: You can customize this high-level summary in your review settings.}

[coderabbitai]

Walkthrough

Adds a Windows-specific test variant gagent_install_no_device and a no_serial variant in the qemu test config that sets gagent_serial_type = none and check_vioser = no. In test code, guest-agent creation is skipped when gagent_serial_type is "none", and the base run_once path is bypassed when gagent_check_type equals install_no_device. New handler methods gagent_check_install_no_device are added for Linux and Windows to verify installation without a virtio-serial device.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

• Inspect qemu/tests/qemu_guest_agent.py: conditional creation of QemuAgent, updated run_once sequencing, and two new gagent_check_install_no_device methods.
• Verify qemu/tests/cfg/qemu_guest_agent.cfg: new gagent_install_no_device and no_serial variants and parameter alignment with code checks.
• Confirm control flow covers Linux and Windows paths and that skipping agent creation has no unintended side effects.

Pre-merge checks and finishing touches

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 44.44% which is insufficient. The required threshold is 80.00%.	You can run @coderabbitai generate docstrings to improve docstring coverage.

✅ Passed checks (2 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title 'qemu_guest_agent: Add test for QGA install without virtio-serial' clearly and specifically describes the main change: adding a new test case for QEMU Guest Agent installation without a virtio-serial device, which aligns directly with the changeset.

✨ Finishing touches

• 📝 Generate docstrings

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

---

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[6-dehan]

@leidwang please help to review when you're free
(1/1) Host_RHEL.m10.u2.ovmf.qcow2.virtio_scsi.up.virtio_net.Guest.Win2025.x86_64.io-github-autotest-qemu.qemu_guest_agent.no_serial.gagent_install_no_device.q35: PASS (104.91 s)

[coderabbitai]

Actionable comments posted: 0

🧹 Nitpick comments (2)

qemu/tests/qemu_guest_agent.py (2)

451-512: gagent_check_install_no_device cleanly covers the no-serial install scenario

This flow (ensure VM, open session, uninstall if present, resolve MSI path via get_qga_pkg_path when available, install using gagent_install_cmd, then assert service status) matches the intent of validating QGA install without a virtio-serial device and relies only on guest-side checks, not self.gagent. The extra get_qga_pkg_path call duplicates some work done in the Windows setup path but is harmless and keeps the test self-contained.

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4681-4682: Windows setup consistently avoids gagent_create for gagent_serial_type = "none"

Mirroring the base class, this guard prevents trying to create a QemuAgent backed by a non-existent serial device in the no_serial variant, without impacting existing virtio/ISA flows. If you touch this again, a small helper like if params.get("gagent_serial_type") != "none": shared between Linux and Windows setups could reduce duplication.

📜 Review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between f5d68b3 and 4f0b173.

📒 Files selected for processing (2)

• qemu/tests/cfg/qemu_guest_agent.cfg (2 hunks)
• qemu/tests/qemu_guest_agent.py (4 hunks)

🔇 Additional comments (4)

qemu/tests/cfg/qemu_guest_agent.cfg (2)

669-672: New Windows gagent_install_no_device variant wiring looks correct

The combination of only Windows, only no_serial, and gagent_check_type = install_no_device cleanly targets the new Python handler without affecting existing variants.

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696-699: no_serial serial variant is safely isolated to the new test

Restricting this variant to only gagent_install_no_device, setting gagent_serial_type = none, and disabling check_vioser ensures no other tests run without a GA channel and that this scenario does not expect virtio-serial.

qemu/tests/qemu_guest_agent.py (2)

430-431: Guarding gagent_create when serial type is "none"

Conditionally skipping gagent_create when gagent_serial_type is "none" avoids constructing a QemuAgent without a backing chardev, while preserving previous behaviour for all other values (including None).

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4429-4431: Skipping base run_once for install_no_device avoids accessing self.gagent

By not calling QemuGuestAgentTest.run_once when gagent_check_type == "install_no_device", this path correctly avoids gagent_verify() in cases where no QemuAgent was created (the no_serial scenario), while all other check types retain the original verification.

[leidwang]

Please add JIRA ID to the PR's description.

[leidwang]

Does this PR need to be reviewed by Boqiao?

[6-dehan]

Does this PR need to be reviewed by Boqiao?

Yes, will add him to review and test later.

[6-dehan]

@fbq815 Could you please help to review when you have a moment?

[coderabbitai]

Actionable comments posted: 1

📜 Review details

Configuration used: CodeRabbit UI

Review profile: CHILL

Plan: Pro

📥 Commits

Reviewing files that changed from the base of the PR and between 4f0b173 and 0f6c21b.

📒 Files selected for processing (2)

• qemu/tests/cfg/qemu_guest_agent.cfg (2 hunks)
• qemu/tests/qemu_guest_agent.py (4 hunks)

🚧 Files skipped from review as they are similar to previous changes (1)

• qemu/tests/cfg/qemu_guest_agent.cfg

🔇 Additional comments (3)

qemu/tests/qemu_guest_agent.py (3)

430-431: LGTM: Conditional agent creation is correctly gated.

The logic appropriately skips guest agent creation when gagent_serial_type is "none", which aligns with the test objective to verify QGA installation without a virtio-serial device.

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4427-4428: LGTM: Correctly bypasses verification for no-device install test.

Skipping the base run_once (which calls gagent_verify) when gagent_check_type is "install_no_device" is appropriate, as verification requires a working virtio-serial channel that won't exist in this test scenario.

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4678-4679: LGTM: Consistent with base class implementation.

The conditional agent creation pattern matches the base class implementation (Lines 430-431), ensuring consistent behavior across Windows and Linux guests.