- name
- dev-testing
- description
- Capsem testing policy and workflow. Use whenever running or writing tests. For VM, hypervisor, frontend, or Python specifics see the dev-testing-* skills.
# Testing
Read `tests/README.md` before adding or moving test fixtures. Test-only config
belongs under `tests/fixtures/`, not root `config/`.
## Where a new guard belongs
A test that records an architectural mistake -- something that must not be
repeated, checkable from source -- is a Citadel guard, in `tests/citadel/`, not
another file at `tests/` root. It runs in the fast phase, so it costs seconds
rather than waiting on an asset build.
Two rules the existing guards follow:
State the reason in a named `*_RATIONALE` appended to the assertion, so a
violation teaches. `test_db_boundary.py` is the model. Where the reason is
already stated canonically -- `config/gate.toml [boundary]`, AGENTS.md, a skill
-- cite it instead of restating it.
Write the adversarial case, not just the conformance case. A guard proved only
by inputs it was built for is not proved. `test_workflow_enforcement.py` carries
fourteen evasions and four legitimate shapes because enumerating bad spellings
let five through; the rule is now a whitelist for that reason.
## Test execution
| Command | What | VM? |
|---------|------|-----|
| `just fast-test` | Incomplete source feedback only | No |
| `just focus-test <group>` | One existing owner; `rust` selects changed crates and reverse dependents | Depends on group |
| `just install` | Complete local macOS package build and native install for hands-on testing | Yes |
| `just test` | Complete local verification; required, passing, before a release | Yes |
A release requires a passing `just test` for its source first; hosted release
lanes then qualify what they publish.
`just fast-test` is incomplete feedback, and `just focus-test <group>` is the normal
targeted regression path. During TDD use the smallest native test; run `just test`
when complete local whole-system verification is useful.
The full gate is a construction boundary, not the edit loop. During TDD,
reproduce the failure with the smallest focused test, run that test red/green,
and batch adjacent parity fixes before paying for the complete gate. Run it
only when explicitly requested. Later fixes use focused owners; a gate-policy
edit is not permission for another full run. The one full run a change always
needs is the passing `just test` a release of it requires; the release command
refuses without it.
`just test` deliberately accepts committed or uncommitted developer work. It
records `HEAD` plus a digest of every tracked and untracked non-ignored source
byte, then fails if either changes while the gate runs. Generated output stays
under ignored build directories. The local proof therefore covers the exact
source state the developer asked to test without forcing commit choreography.
Automatic gate benchmark output belongs under ignored
`cache/target/tests/benchmarks/`. Historical benchmark publication uses the owning
pytest/benchmark command and an explicit review; it is not a Just convenience
recipe.
## Release CI invariant
Release CI reuses the same checked-in private modules as local `just test`:
- `_test-fast`
- `_test-static`
- `_test-artifacts`
- `_test-functional`
- `_test-glowup`
- `_test-release-contracts`
The build scope is selective; the quality scope is not. Binary CI builds only
packages and resolves every channel profile by recorded digest. Profile CI
builds exactly one channel/profile and resolves the current package by recorded
digest. The resolved complementary artifacts are staged into the production
test harness, not replaced by source-built substitutes.
Every activated pairing must pass artifact validation, all VM suites,
Winterfell/MCP lifecycle, IronBank, injection, integration, benchmarks, full
`capsem-doctor`, exact native install, and update glow-up. A staged profile
whose minimum package is not yet satisfied may run only the self-consistency,
integrity, isolation, and boot proof; the following binary lane must run the
complete functional and glow-up modules before activation.
Both macOS and Linux must install their exact publishable native packages,
including their real post-install scripts, before publication. Notarization and
the public stable-to-nightly switch/upgrade glow-up remain mandatory
end-to-end proof.
On Apple Silicon macOS, `just test` owns the pre-publication macOS package
boundary through `build_system/packaging/macos/macos_release_glowup.py`: it builds the package with the
production assembler, installs that exact file in a disposable headless Tart
guest, verifies the receipt, app bundle, complete binary cohort, service and
gateway health, then extracts the same package on the physical Mac and boots a
real Capsem guest VM from its exact binary/profile payload to a shell marker.
The local package is unsigned; its postinstall ad-hoc signs the installed
Mach-O payload with the required entitlements. Local qualification must not
load Developer ID material or create a signing keychain. The tagged publication
workflow alone signs, notarizes, staples, and installs the final publishable
package.
Tart macOS guests do not support nested virtualization, so these are two
explicit halves of one script rather than a claimed nested proof. `just fast-test`
deliberately excludes Tart and therefore cannot be used for release.
Rust is pinned to `1.97.1` across the workspace file, workflow steps,
host-builder, and bootstrap. Change all pin surfaces together in a deliberate
toolchain-bump PR. RustSec and JavaScript bulk advisories are blocking in
`just fast-test`, local `just test`, ordinary CI, and both release lanes,
as well as the scheduled/manual audit. A new advisory fails the candidate
until it is remediated or explicitly reviewed in checked-in scanner policy.
Linux proof is host-aware: a cross-built non-host package receives structural
validation in qualification and exact native installation in its tagged release
job. `CAPSEM_REQUIRE_LINUX_DEB_PROOF=1` must not reject that non-host package
before the host package reaches its mandatory KVM proof. The hosted arm64 runner
does not expose `/dev/kvm`, so it proves exact package/service operation while
the x86_64 runner additionally owns the guest-shell marker.
Expensive harnesses need a cheap clean-environment bootstrap proof at the
start of `just test`, before Docker/Colima or artifact preparation. The one
private `_test-fast` module is also called by `just fast-test`, ordinary CI, and
both release lanes. It owns YAML/workflow and source syntax, source contracts,
dependency audits, Clippy, Python lint/type checks, and JavaScript/frontend
checks; no caller may reproduce a subset inline. Only a green fast gate may
build the Linux install-test image. That preflight must use a
container-owned `UV_PROJECT_ENVIRONMENT` and prove `python -m pytest` launches
before VM, package, or asset work consumes hours. Keep an ordering contract.
It is fail-fast infrastructure
validation only: the later Docker/systemd install E2E remains mandatory and
must still exercise the installed package and post-install behavior.
## Local/CI execution parity
Read `references/local-ci-parity.md` before editing any release workflow, gate
recipe, or CI job. It holds the Ironbank parity rule (every portable release
gate must be owned by `just test`), scanner/tool pinning, Docker platform and
prune discipline, common cache contracts, and the source-guard contracts.
## TDD workflow
Write tests first:
1. Write failing tests that capture expected behavior
2. Verify they fail for the right reason
3. Write minimal implementation to pass them
4. Refactor
Without a failing test first, it's easy to write tests that pass by accident or don't actually verify the behavior you intended.
## Functional slice proof matrix
Every non-trivial feature slice needs evidence in all of these categories before it can be called done. A green unit suite or a benchmark is not a substitute for functional or end-to-end proof.
| Category | What it proves | Minimum expectation |
|----------|----------------|---------------------|
| Unit/contract | Pure logic, parser state machines, schema migration, helper APIs | Red/green tests for normal and edge behavior at the smallest useful boundary |
| Functional | The feature works through its production-facing API, not just private helpers | Exercise the real module boundary with realistic inputs and assert outputs plus side effects |
| Adversarial | The feature preserves security, privacy, and policy invariants when attacked | Malformed, oversized, denied, missing, racing, timeout, permission, and leak-prevention cases |
| E2E/VM | The user-visible path works in a real Capsem session | Boot/run a VM or use the black-box CLI/MCP/service path, then inspect externally visible behavior |
| Telemetry | Audit data is present, accurate, and queryable | Query `session.db` or logger readers for required rows, fields, decisions, errors, and attribution |
| Performance | Hot paths stayed inside the accepted budget | Benchmarks or timing assertions with recorded numbers and regression criteria |
If a category is genuinely impossible or deliberately deferred, record it as missing with a reason, owner, and follow-up task. Silent deferral is the bug. "Covered by later E2E" is not enough unless the tracker names the later test and the current milestone is explicitly scoped as internal-only.
For policy, MITM, MCP, telemetry, networking, filesystem, process lifecycle, or sandbox-boundary work, the functional slice matrix is mandatory. The tests should prove not only that the happy path succeeds, but also that enforcement happens at the intended boundary: a blocked MCP tool does not dispatch, a blocked return does not leak, a denied URL does not reach the network, a malformed frame does not poison the stream, and telemetry records the truth.
## Ironbank ledger tests
Use `/ironbank` for release-critical VM, network, model, MCP, credential
broker, package-manager, doctor, benchmark, and security acceptance proof.
Ironbank lives in `tests/ironbank/` and is full black-box: tests are written
from public contracts, CLI help, docs, generated schemas, hermetic fixtures,
route responses, logs, DB rows, and installed package metadata. Do not inspect
Rust/product internals to decide expected behavior.
Ironbank cannot use:
- `skip`, `skipif`, `slow`, optional markers, or public-network dependencies
- status-code-only replay
- row-exists checks
- parser-only assertions
- manual OAuth/client runs as release proof
One deterministic stimulus must prove the whole ledger path: client result,
parsed facts, CEL/security decision, detection/enforcement rows, protocol DB
rows, structured logs, status counters, UDS route, HTTP route, and UI-facing
JSON. Every emitted DB/log/route field is exact-value asserted, covered by a
typed invariant, or explicitly marked not applicable. Unknown fields fail the
test until the field ledger is updated.
Package-manager tests prove function. Installing `zstd`, for example, means
compressing known bytes, decompressing them, and comparing the exact output;
not just checking dpkg output.
## Logged-data DB ownership
Telemetry and security ledgers are database-owned. Service routes, UI handlers,
MCP helpers, and benchmark harnesses must not build their own logged-data
projection caches and must not open SQLite directly. They may own query intent
(for example the fields a route needs), but they call the logger DB object to
execute it. The logger DB object owns connection threads, `mem`/disk table
layout, write buffering, flush, reload-from-disk behavior, WAL tuning, and
future FTS5/search tables.
Do not move route-specific SQL into `DbWriter` or turn the DB layer into a pile
of route helper methods such as `stats_detail_payload()` just to hide SQL. The
boundary is execution and storage mechanics:
```rust
db.ready().await?;
db.query(sql, params).await?;
db.write(event).await?;
```
`db.write(event).await` means the DB object accepted the event into its
producer buffer. Tests that assert read-after-write rows must use the DB flush
barrier or shutdown/reopen. Do not paper over visibility with sleeps, route
projections, or direct SQLite readers.
Empty table means empty result. Missing table or column means the schema
contract is broken and must fail loudly; never add compatibility branches that
treat missing ledger shape as empty data.
Regression tests must guard the boundary. If a route needs ledger data, add a
test that proves the route uses the DB object and a source guard that rejects
raw `rusqlite` opens, direct `DbReader::open`, and service-owned projection
state in production route code. Add a companion guard that prevents
route-specific DB writer methods or missing-schema fallbacks from being
introduced.
## Mock server boundary
`crates/capsem-mock-server` is the single reusable local fixture server for
benchmarks, doctor, protocol recording/replay, gateway/integration tests, and
Ironbank. It owns mock protocol responses and deterministic local upstream
behavior. Tests may launch it through `build_system/scripts/test/mock_server.py`,
`tests/helpers/mock_server.py`, or `CAPSEM_MOCK_SERVER_BASE_URL`.
Do not add another local HTTP/MCP/OAuth/model mock server for a feature. Extend
the shared mock server and its fixtures instead, then assert the route through
the relevant black-box test.
## Parallel tests as dogfooding (n=4 is non-negotiable)
`just test` runs the python suite under `pytest -n 4 --dist=loadfile`. Four real VMs boot simultaneously. **This is the canary, not just a speed-up.** We ship Capsem as a multi-VM sandbox for AI agents -- if our own test suite cannot safely boot 4 concurrent VMs, real users running an agent farm will hit the exact same bug. Treat any concurrency flake as a Capsem-side bug, not a test-tuning problem:
- "Suspend timed out" under load -> service IPC handling is racy, not "bump the timeout"
- "Session did not become ready" -> Apple VZ resource serialization, VirtioFS lock contention, or service handling concurrent provisions; investigate, don't suppress
- Two tests both want the same VM name -> name-collision bug in `validate_vm_name` / registry, not "isolate test names better"
- Stale socket between tests -> service didn't reap a child cleanly, real production bug
Anti-patterns when a test flakes under `-n 4`:
- Adding `time.sleep()` to "let things settle" -- masking a race
- Bumping the per-test timeout -- buying time for a real bug to manifest in prod instead of CI
- Marking the test `serial` so it runs alone -- defeating the dogfooding signal
The exception is a true timing or benchmark probe whose assertion is the
measured number. Those tests must already be marked `serial` and `just test`
runs them immediately after the `-n 4` canary. That is not a flake escape
hatch: it prevents another benchmark file from stealing the same Apple VZ
launch budget and corrupting the number we are trying to publish.
The host has plenty of headroom (48 GB RAM, 14 cores; 4 VMs at 2 GB / 2 CPU each = 8 GB / 8 cores). If concurrency surfaces a flake, fix the product, then re-run. Bumping `-n` higher (8, 12) is the natural follow-on once n=4 is stable -- real users will run more.
### Orphan processes across runs are a product bug (not a test bug)
If a previous `just test -n 4` run was interrupted (ctrl-C, pytest-xdist worker death, host crash) and the NEXT run flakes with "vm-ready never asserted", UDS "connection refused", or mysterious HTTP 500s -- the cause is companion processes from the interrupted run still alive under PID 1. `pkill -f "cache/target/cargo/debug/capsem-(service|process|gateway|tray|mcp)"` will make the flake vanish, but that is cleanup-after-the-fact. The fix is on the COMPANION side: every spawned companion (gateway, tray, and any new one) must use `capsem-guard::install(parent_pid, lock_path)` to enforce (a) refuse-standalone, (b) singleton, (c) self-exit on parent death. See `/dev-rust-patterns` lesson 18. Regression tests live in `tests/capsem-service/test_companion_lifecycle.py` -- never remove them; when adding a new companion, extend that file.
**Never `pkill -f capsem-` with a broad pattern** during test debugging: `capsem-` matches `--crate-name capsem-core` in running rustc/cargo invocations and will SIGKILL the compiler mid-build. Use a binary-path pattern like `pkill -f "cache/target/cargo/debug/capsem-(service|process|gateway|tray|mcp)"` instead.
### Apple VZ lifecycle serialization is part of the product
Apple's Virtualization.framework does not tolerate overlapping checkpoint
lifecycle operations (`saveMachineStateToURL` and `restoreMachineStateFromURL`)
on sibling VMs, and teardown must not cross those checkpoint edges. Capsem uses
`ServiceState::save_restore_lock` plus the host-wide `VzHostLock` flock:
cold starts and teardown take shared/read guards, save and restore take
exclusive/write guards. The rail holds even when pytest-xdist spawns one
`capsem-service` per worker, while independent cold starts can still run
together for the boot-latency gate.
Do not demote suspend/resume, lifecycle, provisioning, or teardown tests to
`-n 1` to sidestep VZ races. `just test` at `-n 4` is the contract; if a
concurrent run sees restore permission errors, loop-device corruption,
connection-refused startup races, or readiness misses, fix the lifecycle rail.
Full context and failure signatures live in
`web/docs/src/content/docs/gotchas/concurrent-suspend-resume.md`.
## Adversarial testing
Capsem is a security product. Every security-relevant feature needs tests that actively try to break invariants. Think like an attacker:
- Can a corp-blocked domain be snuck through another provider's list?
- Does an overlapping wildcard in allow+block always deny?
- Does malformed input (empty strings, unicode, huge payloads, invalid JSON) get rejected?
- Can path traversal escape the VirtioFS sandbox?
- Can a guest process modify its own binaries?
Stress-test boundary conditions. Write tests for the attacks you'd attempt yourself.
### Security invariants to verify in tests
When touching security-relevant code, check these invariants have test coverage:
| Invariant | What to test | Where |
|-----------|-------------|-------|
| VirtioFS share is `guest/` only | `session_dir/guest/` exists, symlinks resolve, host-only files (`session.db`, `serial.log`) are outside the share | `capsem-core::lib::tests` |
| UDS sockets are 0600 | After bind, verify permissions exclude other users | `capsem-process` |
| Process env is cleared | `env_clear()` called, only allowlisted vars passed | `capsem-service` spawn tests |
| No `process::exit` on guest I/O | Control channel close causes loop break, not exit | `capsem-process` |
| Sensitive logs are 0600 | `serial.log` created with restricted permissions | `capsem-process` |
| Gateway auth on all routes | Every route except `GET /` returns 401 without token | `capsem-gateway::auth::tests` |
| Auth rate limiting | 429 after threshold, resets after window | `capsem-gateway::auth::tests` |
| CORS rejects external origins | Only localhost/127.0.0.1/tauri allowed | `capsem-gateway::tests` |
| Body size limit | 413 for >10MB payloads | `capsem-gateway::proxy::tests` |
| VM ID validation | Path traversal (`../`), dots, spaces, null bytes rejected | `capsem-gateway::terminal::tests` |
| Rootfs read-only | profile rootfs asset mounted ro, guest binaries 555 | `capsem-doctor` in-VM tests |
| Suspend reports errors | IPC failure and timeout both return 500, not silent success | `capsem-service` tests |
## Test fixture anti-pattern: masking races with polling
If all test fixtures wait/poll before asserting, the tests will never catch server-side race conditions. For every endpoint that talks to a VM socket, write at least one test that calls it IMMEDIATELY after provision (no `wait_exec_ready`, no `ready_vm` fixture). The server must handle readiness internally.
**Pattern to avoid** (masks the bug -- server never needs wait logic because client always waits):
```
fixture calls provision -> fixture polls wait_exec_ready -> test calls exec
```
**Required test pattern** (catches the bug -- if server doesn't wait, test fails):
```
test calls provision -> test immediately calls exec -> server handles wait
```
See `tests/capsem-service/test_svc_exec_ready.py` for the regression tests that enforce this.
### wait_exec_ready is a single call, not a loop
`wait_exec_ready` (in `tests/helpers/service.py`, `tests/helpers/mcp.py`, `tests/capsem-gateway/test_gw_e2e.py`) makes one exec call with the server-side timeout passed through. The server's `handle_exec` calls `wait_for_vm_ready` internally, which polls until the VM is ready. Do NOT add client-side retry loops -- that creates a double-wait where each retry can block for the full server timeout (30s client retries x 30s server wait = pathological cascade). One wait, one place.
### Exec latency regression gate
`tests/capsem-serial/test_boot_timing.py::test_exec_latency_within_gate` asserts that provision-to-first-exec completes within `EXEC_LATENCY_GATE`. If this test fails, investigate boot time (process.log boot_timeline spans), not the wait mechanism.
## Where tests live
- **Rust unit: sibling `tests.rs` file, not inline `mod tests { ... }`.** See the next subsection.
- Rust integration: `crates/capsem-core/tests/`
- In-VM diagnostics: `guest/artifacts/diagnostics/test_*.py` (see dev-testing-vm)
- Hypervisor: KVM + Apple VZ tests (see dev-testing-hypervisor)
- Frontend: `web/app/src/lib/__tests__/` (see dev-testing-frontend)
- Python (builder): `tests/test_*.py`
- Python integration (service daemon): `tests/capsem-*/` directories, each with its own conftest.py and pytest marker
- Ironbank release ledger: `tests/ironbank/` (black-box only; no Rust
implementation-derived expectations)
### Rust unit tests: sibling `tests.rs` pattern
Ver no GitHub