feat: added jest expect support

package.json

@@ -61,17 +61,19 @@
     "cli-truncate": "^3.1.0",
     "diff": "^5.0.0",
     "elegant-spinner": "^3.0.0",
+    "expect": "^27.4.2",
     "fast-glob": "^3.2.7",
     "figures": "^4.0.0",
     "find-up": "^6.2.0",
     "happy-dom": "^2.24.5",
+    "jest-matcher-utils": "^27.4.2",
     "jest-snapshot": "^27.4.2",
     "jest-util": "^27.4.2",
     "jsdom": "^19.0.0",
-    "nanoid": "^3.1.30",
     "log-symbols": "^4.1.0",
     "log-update": "^5.0.0",
     "mlly": "^0.3.15",
+    "nanoid": "^3.1.30",
     "picocolors": "^1.0.0",
     "piscina": "^3.1.0",
     "sade": "^1.7.4",

src/index.ts

@@ -1,3 +1,4 @@
+import { MatchersObject } from 'expect/build/types'
 import { UserOptions } from './types'
 
 export * from './types'
@@ -16,6 +17,10 @@ declare module 'vite' {
 
 declare global {
   namespace Chai {
+    interface ExpectStatic {
+      extend(expects: MatchersObject): void
+    }
+
     interface Assertion {
       // Snapshot
       toMatchSnapshot(message?: string): Assertion

src/integrations/chai/jest-extend.ts

@@ -0,0 +1,78 @@
+import chai, { util } from 'chai'
+
+import { MatcherState } from 'expect'
+import { MatchersObject, SyncExpectationResult } from 'expect/build/types'
+
+import {
+  iterableEquality,
+  subsetEquality,
+} from 'expect/build/utils'
+import * as matcherUtils from 'jest-matcher-utils'
+import { ChaiPlugin } from './types'
+
+const isAsyncFunction = (fn: unknown) =>
+  typeof fn === 'function' && (fn as any)[Symbol.toStringTag] === 'AsyncFunction'
+
+const getMatcherState = (assertion: Chai.AssertionStatic & Chai.Assertion) => {
+  const actual = assertion._obj
+  const isNot = util.flag(assertion, 'negate') as boolean
+  const jestUtils = {
+    ...matcherUtils,
+    iterableEquality,
+    subsetEquality,
+  }
+
+  // TODO add to ctx - { error, promise, equals, ...getState() }
+  const matcherState: MatcherState = {
+    isNot,
+    utils: jestUtils,
+    assertionCalls: 0,
+    promise: '',
+    equals: () => true,
+    suppressedErrors: [],
+  }
+
+  return {
+    state: matcherState,
+    isNot,
+    actual,
+  }
+}
+
+function JestExtendPlugin(expects: MatchersObject): ChaiPlugin {
+  return (c, utils) => {
+    Object.entries(expects).forEach(([expectAssertionName, expectAssertion]) => {
+      function expectSyncWrapper(this: Chai.AssertionStatic & Chai.Assertion, ...args: any[]) {
+        const { state, isNot, actual } = getMatcherState(this)
+
+        // @ts-expect-error
+        const { pass, message } = expectAssertion.call(state, actual, ...args) as SyncExpectationResult
+
+        if ((pass && isNot) || (!pass && !isNot))
+          c.expect.fail(message())
+      }
+
+      async function expectAsyncWrapper(this: Chai.AssertionStatic & Chai.Assertion, ...args: any[]) {
+        const { state, isNot, actual } = getMatcherState(this)
+
+        // @ts-expect-error
+        const { pass, message } = await expectAssertion.call(state, actual, ...args) as SyncExpectationResult
+
+        if ((pass && isNot) || (!pass && !isNot))
+          c.expect.fail(message())
+      }
+
+      const expectAssertionWrapper = isAsyncFunction(expectAssertion) ? expectAsyncWrapper : expectSyncWrapper
+
+      utils.addMethod(chai.Assertion.prototype, expectAssertionName, expectAssertionWrapper)
+    })
+  }
+}
+
+export function JestExtend(): ChaiPlugin {
+  return (chai, utils) => {
+    utils.addMethod(chai.expect, 'extend', (expects: MatchersObject) => {
+      chai.use(JestExtendPlugin(expects))
+    })
+  }
+}