save/test/streaming.js

A simple CRUD based persistence abstraction for storing objects to any backend data store. eg. Memory, MongoDB, Redis, CouchDB, Postgres, Punch Card etc.

var assert = require('assert')
var Stream = require('stream').Stream
var streamAssert = require('stream-assert')
var mapSeries = require('async').mapSeries

module.exports = function(idProperty, getEngine) {
  describe('WriteStream', function() {
    it('should be a write stream', function(done) {
      getEngine(function(ignoreError, engine) {
        assert.ok(engine instanceof Stream, 'not a Stream')
        done()
      })
    })

    it('should create new documents when data is written', function(done) {
      getEngine(function(ignoreError, engine) {
        engine
          .pipe(
            streamAssert.first(function(data) {
              assert.deepStrictEqual(data.a, 1)
            })
          )
          .pipe(streamAssert.end(done))

        engine.write({ a: 1 })
        engine.end()
      })
    })

    it('should update documents if data has a idProperty when written to stream', function(done) {
      getEngine(function(ignoreError, engine) {
        engine.create({ a: 1 }, function(ignoreError, existingEntity) {
          engine
            .pipe(
              streamAssert.first(function(data) {
                assert.strictEqual(data.a, 2)
                assert.strictEqual(existingEntity._id, data._id)
              })
            )
            .pipe(streamAssert.end(done))

          engine.write({ _id: existingEntity._id, a: 2 })
          engine.end()
        })
      })
    })

    it('should insert if idProperty is given but not found', function(done) {
      getEngine(function(ignoreError, engine) {
        engine
          .pipe(
            streamAssert.first(function(data) {
              assert.strictEqual(data.a, 2)
            })
          )
          .pipe(streamAssert.end(done))

        engine.write({ _id: 1, a: 2 })
        engine.end()
      })
    })
  })

  describe('ReadStream', function() {
    it('should return ReadStream if no callback is provided', function(done) {
      getEngine(function(ignoreError, engine) {
        assert.ok(engine.find({}) instanceof Stream, 'not a instance of Stream')
        done()
      })
    })

    it('should stream result data via ‘objectIdToString’ transformation', function(done) {
      getEngine(function(ignoreError, engine) {
        mapSeries(
          [
            { a: 1, b: 0 },
            { a: 2, b: 0 }
          ],
          engine.create,
          function(ignoreError, documents) {
            var stream = engine.find({ b: 0 })
            stream
              .pipe(
                streamAssert.first(function(data) {
                  assert.deepStrictEqual(data, documents[0])
                })
              )
              .pipe(
                streamAssert.second(function(data) {
                  assert.deepStrictEqual(data, documents[1])
                })
              )
              .pipe(streamAssert.end(done))
          }
        )
      })
    })

    it('should emit `received`', function(done) {
      getEngine(function(ignoreError, engine) {
        mapSeries(
          [
            { a: 1, b: 0 },
            { a: 2, b: 0 }
          ],
          engine.create,
          function(ignoreError, documents) {
            var receivedData = []
            engine.on('received', function(data) {
              receivedData.push(data)
              if (data.length === 2) {
                done()
              } else if (data.length > 2) {
                done(new Error('Too many events emitted'))
              }
            })
            var stream = engine.find({ b: 0 })
            stream
              .pipe(
                streamAssert.first(function(data) {
                  assert.deepStrictEqual(data, documents[0])
                })
              )
              .pipe(
                streamAssert.second(function(data) {
                  assert.deepStrictEqual(data, documents[1])
                })
              )
              .pipe(streamAssert.end(done))
          }
        )
      })
    })
  })
}