Unit testing neo4j-driver errors

[pito-svk]

I would like to unit test my function which takes Neo4jError as first argument for example.

I have a function to properly format neo4j driver errors:

exports.formatErrors = () => {
  return (err, req, res, next) => {
    let error

    if (err.fields) {
      const singleError = err.fields[0]
      const errorName = _.last(singleError.code.split('.'))

      if (errorName === 'ConstraintValidationFailed') {
        const field = singleError.message.split('"')[1]
        error = new ValidationError(`${field} already exists`)
      }
    }

    if (!error) error = err

    next(error)
  }
}

The point is, that I would like to mock this error for example:

Structure {
  signature: 127,
  fields:
   [ { code: 'Neo.ClientError.Schema.ConstraintValidationFailed',
       message: 'Node 0 already exists with label User and property "email"=[john@doe.com]' } ] }

Is it possible to get Neo4jError class from this module and create error mock from this?

Thanks!

[lutovich]

Hi @pito-svk,

I think Neo4jError is exported alongside functions like driver() and auth(). Following code works for me:

var neo4j = require('neo4j-driver').v1;
var error = new neo4j.Neo4jError('Hi, I am an error', 'This is my error code');
console.log(error);

Do you think it is enough to test formatErrors function?

Thanks.

[pito-svk]

What about struct with signature and fields? This is the error object I get when try to create node with uniqueness constraint.

[lutovich]

@pito-svk I think the whole Structure object is exposed by mistake. What you see here is just a raw Bolt protocol message. We should construct a Neo4jError from it and pass it to the catch()/onError() callbacks. I'll create a task for us to fix this.

Thanks a lot for reporting the problem!

[lutovich]

Hi @pito-svk, we've just released 1.1.1 version of the driver with the mentioned errors fix. Now all thrown errors should be of type Neo4jError. Hope the fix works for you, please feel free to create a new issue or update this one if it does not.