Test plugins - sndbox docs

Guest tests

sandbox plugin test .

The command runs cargo test against guest/Cargo.toml.

MockHost

MockHost records calls and accepts typed handlers:

import { MockHost } from "@sandbox/plugin-sdk";

const host = new MockHost().on("time", () => ({
  value: "2026-08-31T12:00:00Z",
  diagnostics: []
}));

const response = await host.call({ operation: "time" });
console.log(response.value, host.calls);

The mock rejects secret-shaped credential output so unit tests do not normalize a behavior production blocks.

Coverage to include

valid and invalid input/config/output schemas;
provider errors and rate-limit diagnostics;
cancellation and timeout;
retry and idempotency behavior;
every migration handler;
absence of undeclared calls; and
redaction of logs and errors.

Repository integration tests compile the example guests to wasm32-unknown-unknown and run them through sandbox-plugin-runtime, not a JavaScript replacement. Runtime tests enforce missing ambient imports, memory, fuel, time, network, storage, signature, tamper, and revocation controls.