nedb/test_lac/openFds.test.js

const fs = require('fs')
const fsPromises = fs.promises
const Nedb = require('../lib/datastore')
const N = 64

// A console.error triggers an error of the parent test

const test = async () => {
  let filehandles = []
  try {
    for (let i = 0; i < 2 * N + 1; i++) {
      const filehandle = await fsPromises.open('./test_lac/openFdsTestFile', 'r')
      filehandles.push(filehandle)
    }
    console.error('No error occurred while opening a file too many times')
    process.exit(1)
  } catch (error) {
    if (error.code !== 'EMFILE') {
      console.error(error)
      process.exit(1)
    }
  } finally {
    for (const filehandle of filehandles) {
      await filehandle.close()
    }
    filehandles = []
  }

  try {
    for (let i = 0; i < N; i++) {
      const filehandle = await fsPromises.open('./test_lac/openFdsTestFile2', 'r')
      filehandles.push(filehandle)
    }
  } catch (error) {
    console.error(`An unexpected error occurred when opening file not too many times with error: ${error}`)
    process.exit(1)
  } finally {
    for (const filehandle of filehandles) {
      await filehandle.close()
    }
  }

  try {
    const db = new Nedb({ filename: './workspace/openfds.db' })
    await db.loadDatabaseAsync()
    await db.removeAsync({}, { multi: true })
    await db.insertAsync({ hello: 'world' })

    for (let i = 0; i < 2 * N + 1; i++) {
      await db.persistence.persistCachedDatabaseAsync()
    }
  } catch (error) {
    console.error(`Got unexpected error during one persistence operation with error: ${error}`)
  }
}
try {
  test()
} catch (error) {
  console.error(error)
  process.exit(1)
}