[sunli829]

Summary

nsh/test's matchers compared values through JSON: undefined equalled null, dates, maps, sets and typed arrays lost their contents, toBe was structural and a RegExp ran in Rust's syntax. This makes them Jest's (decided in the API review before the first recorded release):

• toBe is Object.is.
• toEqual is Jest's recursive equality: classes, undefined properties as missing ones, dates by time, regular expressions by source and flags, maps and sets by entries, buffers and typed arrays by bytes, cycles.
• toMatchObject uses it for its leaves; toContain is ===, toContainEqual structural.
• A RegExp given to toMatch / toThrow runs on the JS engine.
• Values are kept as JS made them and compared in Rust over the VM (nsh-testing values.rs), never through JSON.
• Selector regexes stay matched in Rust (off the JS thread, or on a real host's agent); their docs now say Rust's regex syntax.

Public API

• nsh_core::element::JsClass — #[non_exhaustive] enum { Array, Function, Date, RegExp, Map, Set, Error, ArrayBuffer, View(&'static str), Object, … }: the class of a JS object, what toEqual compares by.
• JsIn::class(&self) -> Option<JsClass> — a value's class.
• JsIn::same_value(&self, other: JsIn<'_>) -> bool — Object.is.
• JsIn::as_buffer(&self) -> Option<Vec<u8>> — an ArrayBuffer's or a view's bytes.
• JsIn::iterate(&self) -> Result<Option<Vec<JsOwned<'a>>>, PropError> — the items of an iterable.
• JsIn::invoke(&self, name: &str, args: &[JsIn<'_>]) -> Result<JsOwned<'a>, PropError> — call a method.
• JsHost::{class, same_value, buffer, iterate, invoke} — the host side of the above, with defaults for hosts that have none.
• nsh/test: expect's matchers keep their names and signatures; their meaning is Jest's.

Test

• cargo test -p nsh-testing --features js,bundle,agent (new tests/testing/expect/Expect.test.ts), -p nsh-js, -p nsh-core
• nsh test of gallery (223), gallery-rs (74), counter, embedded, host-echo, rust-exports
• cargo clippy --workspace --all-targets, web clippy

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