expect().resolves and expect().rejects

[Electroid]

Adds support for:

import { test } from "bun:test";

test("resolves and rejects", () => {
  expect(Promise.resolve()).resolves.toBeUndefined();
  expect(Promise.reject(new Error()).rejects.toBeInstanceOf(Error);
});

[Electroid]

Also, you'll want to review this PR per-commit, since the first commit is just moving code from 1 file to several.

[github-actions]

❌ @Jarred-Sumner 10 files with test failures on bun-darwin-aarch64:

• test/bundler/bundler_browser.test.ts
• test/bundler/esbuild/default.test.ts
• test/bundler/esbuild/importstar.test.ts
• test/cli/install/bunx.test.ts
• test/js/bun/eventsource/eventsource.test.ts
• test/js/bun/test/test-test.test.ts
• test/js/bun/websocket/websocket-server.test.ts
• test/js/third_party/socket.io/socket.io-close.test.ts
• test/js/web/fetch/fetch-leak.test.js
• test/js/web/websocket/websocket.test.js

View test output

^{#28546b1c03ad8c09cd0087ad4dc3308b61c04755}

[github-actions]

❌ @Jarred-Sumner 8 files with test failures on linux-x64-baseline:

• test/bundler/bundler_browser.test.ts
• test/bundler/esbuild/default.test.ts
• test/bundler/esbuild/importstar.test.ts
• test/cli/install/bunx.test.ts
• test/js/bun/util/inspect.test.js
• test/js/bun/websocket/websocket-server.test.ts
• test/js/third_party/prisma/prisma.test.ts
• test/js/web/websocket/websocket.test.js

View test output

^{#28546b1c03ad8c09cd0087ad4dc3308b61c04755}

[github-actions]

❌ @Jarred-Sumner 9 files with test failures on linux-x64:

• test/bundler/bundler_browser.test.ts
• test/bundler/esbuild/default.test.ts
• test/bundler/esbuild/importstar.test.ts
• test/cli/install/bunx.test.ts
• test/js/bun/util/inspect.test.js
• test/js/bun/websocket/websocket-server.test.ts
• test/js/third_party/prisma/prisma.test.ts
• test/js/third_party/socket.io/socket.io-close.test.ts
• test/js/web/websocket/websocket.test.js

View test output

^{#28546b1c03ad8c09cd0087ad4dc3308b61c04755}

[github-actions]

❌ @Jarred-Sumner 10 files with test failures on bun-darwin-x64-baseline:

• test/bundler/bundler_browser.test.ts
• test/bundler/esbuild/default.test.ts
• test/bundler/esbuild/importstar.test.ts
• test/cli/install/bunx.test.ts
• test/cli/test/bun-test.test.ts
• test/js/bun/spawn/spawn-streaming-stdin.test.ts
• test/js/bun/sqlite/sqlite.test.js
• test/js/bun/websocket/websocket-server.test.ts
• test/js/web/timers/setTimeout.test.js
• test/js/web/websocket/websocket.test.js

View test output

^{#28546b1c03ad8c09cd0087ad4dc3308b61c04755}

[Jarred-Sumner]

@Electroid we want mark the Promise as handled. Promises internally hold a state flag. Promise.reject() goes into the rejection queue immediately, but then at the end of the next tick, when promise rejections are drained, we check if the rejected Promise was handled. If handled, it is not reported.

You'll need to read JSC's code to figure out exactly where, but it will ultimately be an |= on this flag:

bun/src/bun.js/bindings/bindings.cpp

Line 2451 in 669e789

promise->internalField(JSC::JSPromise::Field::Flags).set(arg0->vm(), promise, jsNumber(static_cast<unsigned>(JSC::JSPromise::Status::Fulfilled)));

[Jarred-Sumner]

The main question here is if value will need to be wrapped in a Promise as well.

The pattern is

await expect(fetch(url)).resolves.toBeInstanceOf(Response)

Sometimes, people do this:

try {
   expect(123).toBe(456);
} catch (e) {

} 

So if they do that with a Promise and call .then, .catch, .finally etc, their code will throw an error.