| name | dev-testing-vm |
| description | In-VM diagnostics and test fixtures for Capsem. Use when working with capsem-doctor, adding new in-VM tests, debugging test failures inside the guest, inspecting session databases, or updating the test fixture. Covers the full capsem-doctor test suite, how to run subsets, how to add new VM tests, session inspection, and fixture management. |
In-VM Testing
capsem-doctor
The diagnostic suite runs inside the guest VM via pytest. Tests live in guest/artifacts/diagnostics/ and are baked into the rootfs.
Running diagnostics
just exec "capsem-doctor"
just exec "capsem-doctor -k sandbox"
just exec "capsem-doctor -k network"
just exec "capsem-doctor -x"
Test categories
| File | What it verifies |
|---|
test_sandbox.py | Read-only rootfs, binary permissions, setuid/setgid, kernel hardening (no modules, no debugfs, no IPv6, no swap), process integrity, network isolation (dummy0, fake DNS, iptables) |
test_network.py | MITM CA in system store + certifi, curl without -k, Python urllib HTTPS, CA env vars, HTTP/80 blocked, non-443 blocked, direct IP blocked, multi-domain DNS, AI provider domains |
test_environment.py | TERM/HOME/PATH env vars, bash shell, kernel version, aarch64 arch, mount points, tmpfs |
test_runtimes.py | Python3, Node.js, npm, pip3, git version checks, Python/Node file I/O, git workflow |
test_utilities.py | ~36 unix utilities (coreutils, text processing, network, system tools) |
test_workflows.py | Text write/read, JSON roundtrip, shell pipes, large file (10MB) |
test_ai_cli.py | claude/gemini/codex installed and executable |
test_virtiofs.py | VirtioFS mount, ext4 loopback, workspace I/O, pip install, file delete+recreate |
Adding new in-VM tests
- Add test functions to the appropriate
guest/artifacts/diagnostics/test_*.py or create test_<category>.py
- Use
from conftest import run for shell commands, output_dir fixture for temp files
- Tests auto-skip outside the capsem VM (conftest checks for root + writable /root)
- Rebuild rootfs with
just build-assets to bake new test files into the image
- For fast iteration during development, tests in
diagnostics/ are also repacked into the initrd by just run, so just exec "capsem-doctor" picks up changes without a full rootfs rebuild
- Verify:
just exec "capsem-doctor -k <your_test>"
Session inspection
After running a VM session, inspect the telemetry database:
just inspect-session
just inspect-session <session-id>
just inspect-session --list
just inspect-session -n 10
Checks: session ledgers exist (net_events, model_calls, tool_calls, tool_responses, fs_events, dns_events, security_rule_events), row counts, orphaned tool_calls, AI-provider consistency.
Verifying telemetry pipelines
Each pipeline can be tested with a targeted VM command:
- fs_events:
just exec 'touch /root/test.txt && sleep 1' then just inspect-session
- net_events:
just exec 'curl -s https://api.anthropic.com/ && sleep 1'
- model_calls/tool_calls: boot interactively, run
claude -p "what is 2+2"
- MCP-origin tool_calls: boot interactively, run
claude -p "use fetch to get https://example.com" and query tool_calls WHERE origin = 'mcp'
If events are missing: check boot logs for daemon startup, vsock connection acceptance, and whether the VM lived long enough for the debouncer to flush (add sleep 1).
Test fixture
The fixture (data/fixtures/test.db) is a real session DB shared by frontend mock mode and Rust roundtrip tests. No synthetic data.
Updating the fixture
python3 scripts/integration_test.py --binary target/debug/capsem --assets assets
just inspect-session <session-id>
just update-fixture ~/.capsem/sessions/<id>/session.db
cargo test --workspace
The fixture must contain: both allowed and denied net_events, created/modified/deleted fs_events, model_calls with cost > 0, tool_calls with origin populated.
