Added some tests

Author: nicolas-van

package.json

@@ -36,7 +36,7 @@
   "scripts": {
     "build": "rollup -c rollup.config.js",
     "test": "npm run lint && npm run coverage",
-    "coverage": "npm run jest -- --coverage",
+    "coverage": "npm run jest -- --coverage --verbose",
     "lint": "eslint -c .eslintrc.cjs \"src/**/*.mjs\"",
     "jest": "cross-env NODE_OPTIONS=--experimental-vm-modules jest",
     "docs": "jsdoc -c .jsdoc.json && node dev/docs-collect-version-numbers.cjs"

src/asyncGeneratorMap.test.mjs

@@ -597,7 +597,7 @@ test('asyncGeneratorMap infinite sync operator', async () => {
   expect(results[2]).toStrictEqual(4)
 })
 
-test('asyncGeneratorMap respect concurrency', async () => {
+test('asyncGeneratorMap blocks when concurrency reached', async () => {
   const callList = []
   const d = new Deferred()
   const p = asyncIterableToArray(asyncGeneratorMap(range(10), async (el, i) => {
@@ -611,3 +611,24 @@ test('asyncGeneratorMap respect concurrency', async () => {
   const result = await p
   expect(result).toStrictEqual(await asyncIterableToArray(range(10)))
 })
+
+test('asyncGeneratorMap reaches concurrency', async () => {
+  const expectedConcurrency = 10
+  let currentConcurrency = 0
+  let maxConcurrency = 0
+  const d = new Deferred()
+  const p = asyncIterableToArray(asyncGeneratorMap(range(100), async (el, i) => {
+    currentConcurrency += 1
+    maxConcurrency = Math.max(maxConcurrency, currentConcurrency)
+    await d.promise
+    currentConcurrency -= 1
+    maxConcurrency = Math.max(maxConcurrency, currentConcurrency)
+    return el
+  }, expectedConcurrency))
+  await asyncDelay()
+  expect(maxConcurrency).toStrictEqual(expectedConcurrency)
+  d.resolve()
+  const result = await p
+  expect(maxConcurrency).toStrictEqual(expectedConcurrency)
+  expect(result).toStrictEqual(await asyncIterableToArray(range(100)))
+})