From 787904d3eff73f515d0c732037da24d9d5507b14 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Timoth=C3=A9e=20Rebours?= <tim@seald.io>
Date: Tue, 16 Nov 2021 14:18:08 +0100
Subject: [PATCH] executor async tests

---
 test/db.test.js             | 13 ------
 test/executor.async.test.js | 85 +++++++++++++++++++++++++++++++++++++
 2 files changed, 85 insertions(+), 13 deletions(-)
 create mode 100755 test/executor.async.test.js

diff --git a/test/db.test.js b/test/db.test.js
index a11fef2..82332d2 100755
--- a/test/db.test.js
+++ b/test/db.test.js
@@ -431,12 +431,10 @@ describe('Database', function () {
     it('If the callback throws an uncaught exception, do not catch it inside findOne, this is userspace concern', function (done) {
       let tryCount = 0
       const currentUncaughtExceptionHandlers = process.listeners('uncaughtException')
-      const currentUnhandledRejectionHandlers = process.listeners('unhandledRejection')
 
       let i
 
       process.removeAllListeners('uncaughtException')
-      process.removeAllListeners('unhandledRejection')
 
       process.on('uncaughtException', function MINE (ex) {
         process.removeAllListeners('uncaughtException')
@@ -449,17 +447,6 @@ describe('Database', function () {
         done()
       })
 
-      process.on('unhandledRejection', function MINE (ex) {
-        process.removeAllListeners('unhandledRejection')
-
-        for (i = 0; i < currentUnhandledRejectionHandlers.length; i += 1) {
-          process.on('unhandledRejection', currentUnhandledRejectionHandlers[i])
-        }
-
-        ex.message.should.equal('SOME EXCEPTION')
-        done()
-      })
-
       d.insert({ a: 5 }, function () {
         // eslint-disable-next-line node/handle-callback-err
         d.findOne({ a: 5 }, function (err, doc) {
diff --git a/test/executor.async.test.js b/test/executor.async.test.js
new file mode 100755
index 0000000..d57127e
--- /dev/null
+++ b/test/executor.async.test.js
@@ -0,0 +1,85 @@
+/* eslint-env mocha */
+const testDb = 'workspace/test.db'
+const { promises: fs, constants: fsConstants } = require('fs')
+const assert = require('assert').strict
+const path = require('path')
+const Datastore = require('../lib/datastore')
+const Persistence = require('../lib/persistence')
+
+// Test that operations are executed in the right order
+// We prevent Mocha from catching the exception we throw on purpose by remembering all current handlers, remove them and register them back after test ends
+const testRightOrder = async d => {
+  const docs = await d.findAsync({})
+  assert.equal(docs.length, 0)
+
+  await d.insertAsync({ a: 1 })
+  await d.updateAsync({ a: 1 }, { a: 2 }, {})
+  const docs2 = await d.findAsync({})
+  assert.equal(docs2[0].a, 2)
+  d.updateAsync({ a: 2 }, { a: 3 }, {}) // not awaiting
+  d.executor.pushAsync(async () => { throw new Error('Some error') }) // not awaiting
+  const docs3 = await d.findAsync({})
+  assert.equal(docs3[0].a, 3)
+}
+
+// Note:  The following test does not have any assertion because it
+// is meant to address the deprecation warning:
+// (node) warning: Recursive process.nextTick detected. This will break in the next version of node. Please use setImmediate for recursive deferral.
+// see
+const testEventLoopStarvation = async d => {
+  const times = 1001
+  let i = 0
+  while (i < times) {
+    i++
+    d.findAsync({ bogus: 'search' })
+  }
+  await d.findAsync({ bogus: 'search' })
+}
+
+// Test that operations are executed in the right order even with no callback
+const testExecutorWorksWithoutCallback = async d => {
+  d.insertAsync({ a: 1 })
+  d.insertAsync({ a: 2 })
+  const docs = await d.findAsync({})
+  assert.equal(docs.length, 2)
+}
+
+describe('Executor async', function () {
+  describe('With persistent database', async () => {
+    let d
+
+    beforeEach(async () => {
+      d = new Datastore({ filename: testDb })
+      assert.equal(d.filename, testDb)
+      assert.equal(d.inMemoryOnly, false)
+      await Persistence.ensureDirectoryExistsAsync(path.dirname(testDb))
+      try {
+        await fs.access(testDb, fsConstants.FS_OK)
+        await fs.unlink(testDb)
+      } catch (err) {}
+      await d.loadDatabaseAsync()
+      assert.equal(d.getAllData().length, 0)
+    })
+
+    it('Operations are executed in the right order', () => testRightOrder(d))
+
+    it('Does not starve event loop and raise warning when more than 1000 callbacks are in queue', () => testEventLoopStarvation(d))
+
+    it('Works in the right order even with no supplied callback', () => testExecutorWorksWithoutCallback(d))
+  })
+}) // ==== End of 'With persistent database' ====
+
+describe('With non persistent database', function () {
+  let d
+
+  beforeEach(async () => {
+    d = new Datastore({ inMemoryOnly: true })
+    assert.equal(d.inMemoryOnly, true)
+    await d.loadDatabaseAsync()
+    assert.equal(d.getAllData().length, 0)
+  })
+
+  it('Operations are executed in the right order', () => testRightOrder(d))
+
+  it('Works in the right order even with no supplied callback', () => testExecutorWorksWithoutCallback(d))
+}) // ==== End of 'With non persistent database' ====