<p align="center">
<img src="https://raw.githubusercontent.com/dragginzgame/shared-assets/main/ic-testkit/ic-testkit-readme-header.svg" alt="IC Testkit — Internet Computer helper library" width="100%">
</p>
# ic-testkit
PocketIC-oriented test utilities for Internet Computer canister tests.
```toml
[dev-dependencies]
ic-testkit = "0.64"
ic-platform = { version = "0.6", features = ["pocket-ic"] }
```
For typed application calls, enable the `wire` feature and depend directly on
`ic-wire` for method contracts. Testkit does not own Candid codecs or call helpers.
The published MSRV is Rust 1.91, and the selected PocketIC line is 16.
Canisters using benchmark markers can add the crate under `[dependencies]`.
The Wasm library uses Platform's raw counters and marker logging,
without a canister SDK or Candid; `fake_principal` retains PocketIC’s principal identity through
`ic_platform::principal::ExternalPrincipal`, without enabling Candid on Wasm.
`pic` is host-only. `performance` is Wasm-only;
`benchmark` counters, parsing and aggregation, and `fake_principal` are available on both
targets. Native CSV and Markdown directory output lives in the repository's
`benchmark_report` example. Standalone recipe builders return
`std::io::Result<StandaloneCanisterFixture>`.
External interfaces that require Candid remain caller-owned: use a direct
Platform dependency for encoding/decoding and PocketIC's raw byte operations.
PocketIC retains its upstream Candid dependencies; Testkit's Wasm profile remains
Candid-free.
The optional native `wire` feature adds `pic::query_wire` and `pic::update_wire`.
Enable it on your Testkit dependency and declare `ic-wire = "0.5"` for your method
contracts. Each helper takes an explicit target/caller
and borrowed request; the Method owns the exact name, identity, types and finite
limits. It executes one PocketIC operation without update retries; a refused reply
does not prove absence of effects. It preserves
application-level results. `WireCallError` retains typed codec causes, complete
structured rejections and the existing transport classification. Unrelated panic
payloads resume. Display omits payloads; raw calls remain available for malformed
requests and original-byte evidence. Reply admission follows PocketIC's allocation,
so it supplies no network pre-allocation or peak-heap guarantee. The feature is off
by default and adds no Wire dependency to the canister library graph.
Requests may use borrowed bounded fields. Responses must implement
`serde::de::DeserializeOwned` because the helper releases the received buffer
before returning; generic callers must carry that bound alongside `M: Method`.
This is the PocketIC package in the IC Tooling workspace. It provides:
- optional typed Wire query/update helpers with contextual, structured errors
- `try_pocket_ic_operation` for recognized synchronous transport panics, preserving
upstream results and unrelated panics without automatic replay
- canister install and retry helpers
- explicit PocketIC startup, retained server/instance ownership, fallible async construction, and
structured child/readiness failures
- explicit authenticated `ic-testkit-server setup`, offline `check`, and a shared
environment startup contract with `ic-testkit-server run -- COMMAND`
for suites spanning several test processes
- one recipe baseline pool for single- and multi-canister PocketIC reuse
- deterministic fake principals
- controller-aware, caller-labeled collect-all diagnostics
- explicit diagnostic reporting to a caller-selected writer, containing secondary
collection and output panics
- compact benchmark marker parsing, aggregation and comparison
- canister-side `performance::measure` marker emission
`ic-testkit` does not wrap the PocketIC simulator API or serialize independent
instances. `pic::server_assets` owns explicit server provisioning and offline
verification for Rust callers and the published CLI; tests never install implicitly.
Rust fixtures call `server_assets::check(&directory)` and pass the returned
absolute executable path to `PocketIcStartupConfig::Spawn`, without invoking the CLI.
Explicit `server_assets::setup` takes a caller-owned cancellation predicate.
Tests normally retain one
`PocketIcInstance<PocketIc>` and use `owned.instance` for simulator operations;
focused extension traits provide reusable harness behavior. Import all upstream
client and DTO identities directly from `ic_platform::pocket_ic`; Testkit owns no
parallel import path. Platform owns additions to that explicit surface.
```bash
cargo install --locked --features cli ic-testkit
ic-testkit-server setup
ic-testkit-server check
ic-testkit-server run -- cargo test --locked
```
The `cli` feature builds the server command; library-only consumers omit it.
For Shared Tooling's lockfile-selected installer, also pass `--features cli`:
```bash
bash scripts/dev/install-rust-tools.sh --consumer "$PWD" \
--package ic-testkit --lockfile Cargo.lock --bin ic-testkit-server \
--profile release --features cli
```
Setup selects Testkit's reviewed PocketIC 16.1.0 archive for Linux x86-64,
macOS Intel or macOS Apple Silicon. It authenticates the archive's pinned digest,
bounds decompression and admits executable bytes/version before publication.
Setup/check print the absolute executable path; diagnostics go to stderr.
`--directory DIRECTORY` selects a physical root (default
`.tools/ic-testkit-server` in the working directory). Checks and run never
download, update or repair a server. Failed attempts and previous bundles remain
retained; a changed installation requires a fresh selected root.
Run uses that prepared selection when neither `POCKET_IC_BIN` nor
`IC_TESTKIT_POCKET_IC_URL` is selected, and exports the executable and managed
URL to the command. Explicit binary overrides admit stable 16.x servers,
independently of the Rust client's latest download constant. URL mode borrows an
existing server. For long pre-client work, select `run --idle-ttl SECONDS -- COMMAND`
or the `Spawn` variant's `server_idle_ttl` field. This selects operation-idle
lifetime independently of `--ttl`'s hard limit; omitted idle selection retains
PocketIC's default. Both options require owned-server mode and positive seconds.
Most users should read the
[repository README](https://github.com/dragginzgame/ic-tooling#readme) for
setup, examples, local checks, and release notes.
The [documentation index](https://github.com/dragginzgame/ic-tooling/blob/main/docs/testkit/README.md)
links current usage guidance and historical design records.
Startup failures expose `PocketIcStartupError::failure()`
and `PocketIcStartupFailure` for cause matching. Read bounded server excerpts
through `output()`, and inspect typed secondary failures through
`command_cleanup()` and `server_cleanup()`. The original cause remains primary;
raw output files remain caller-owned.
Use direct `ic-host-artifacts`, `ic-host-fs` and `ic-host-process` dependencies
for generic artifact streams, filesystem operations and process custody. Testkit
selects gzip for its reviewed PocketIC server assets; its normal dependency graph
does not select Host's Wasm-inspection feature. Consumers select the capabilities
they use rather than inheriting them through Testkit.
The published archive includes [`CHANGELOG.md`](CHANGELOG.md) for historical
upgrade actions. Current build and artifact-cache contracts belong to IC Build;
historical Testkit artifact imports are not current entry points.
The repository also includes a complete
[multi-canister baseline recipe](https://github.com/dragginzgame/ic-tooling/blob/main/crates/ic-testkit/examples/multi_canister_baseline_pool.rs)
compiled by the crate's normal all-target checks. The
[transactional external-artifact example](https://github.com/dragginzgame/ic-tooling/blob/main/crates/ic-build/examples/transactional_artifact_cache.rs)
is compiled and maintained by IC Build.
Benchmark aggregate/comparison rows and aggregate errors expose
`scope: BenchmarkScope::{Suite, All}` for their identity; `average(scale)` returns
checked floor-rounded `u128` means with Testkit's `BenchmarkAverageError`.
`compare_benchmark_aggregates(current, previous, scale)` returns
current/previous means and run counts, preserving missing rows and measured zero.
Approximate percentage fields are removed. Aggregate CSV/text uses scale one in
original counter units; comparison CSV includes both scales. Exact totals remain
available, and zero runs/scaled overflow return typed errors. Write the changed
columns to new report directories; retained reports are not reinterpreted.
Baseline recipes construct `ResetRequirements { funding, policies }` with the
fixed optional fields in `ResetPolicies`. Their resets independently report
`ResetReceipt { policies }`; absence differs from an explicit irrelevant policy. The pool
restores the captured snapshots with the selected funding; successful manual
restoration returns unit. `ResetReceipt` covers non-snapshot guarantees. These are source API hard cuts.
Generic Cargo/Wasm builds, retained artifact caches and freshness APIs belong to
[IC Build](https://github.com/dragginzgame/ic-build). Depend on it directly and use
`ic_build::artifacts`; Testkit keeps PocketIC lifecycle and benchmark policy.
Pass `fixture.pocket_ic()` and `fixture.canister_id()` explicitly to
`query_wire` or `update_wire` with the `wire` feature. The standalone fixture owns
installation and lifetime; Wire owns method contracts and codec limits.
See the [packaged migration notes](CHANGELOG.md).
Benchmark commands own run identities, provenance, history selection and any
metadata sidecars. The repository's `benchmark_report` example renders supplied
measurements as CSV and Markdown; it has no metadata schema, reader or
history-discovery policy.
### Raw reply canister fixtures
Enable `ic-testkit`'s `reply-fixtures` feature to use
`pic::fixtures::raw_reply_canister`. Supply exact raw reply bytes and explicit
aggregate method-count, UTF-8 method-name and reply-byte ceilings. Empty or
control-containing names, duplicate exports and unsupported Wasm32 extents are
rejected before encoding. Method names must be unique across query and update exports.
The generated memory has a fixed maximum and can hold replies spanning pages.
This helper does not decode Candid, install canisters, select principals or fund
instances; keep product reply catalogs and assertions in the consuming tests.## Toolchains and checks
Testkit is part of the IC Tooling workspace. Use the root
[host guide](../../docs/hosts.md) and [publication guide](../../docs/publishing.md)
for setup and coordinated releases.
- `make testkit-check`: Testkit libraries and private driver with the prepared server.
- `make testkit-wasm-check` and `make testkit-msrv`: deployed profiles.
- `make testkit-package-check`: all coordinated public archives, including tests.
- `make testkit-browser-check`: browser-session support.
The [0.62 migration](../../docs/changelog/0.62.md) replaces the old independent
Testkit release flow. The root changelog owns new releases; the package changelog
retains published history. Neither package checking nor ordinary validation
authorizes downloads, publication or artifact cleanup.