[JavaScript] Scoped packages throw SyntaxError when running tests

Description

When passing a scoped npm package (@scope/my-project) to the projectName argument, it seems to produce test files that are not valid syntax, due to the @ symbol.

SyntaxError: /Users/jgoldsmith/Sites/personal/my-project/test/api/AuthApi.spec.js: Unexpected token (23:30)
  21 |   } else {
  22 |     // Browser globals (root is window)
> 23 |     factory(root.expect, root.@ScopeMyProject);
     |                               ^
  24 |   }
  25 | }(this, function(expect, @ScopeMyProject) {
  26 |   'use strict';

Swagger-codegen version

2.4.0

Command line used for generation

docker run \
  --rm \
  --volume ${PWD}:/local \
  swaggerapi/swagger-codegen-cli \
  generate \
    --input-spec http://localhost:3000/v1/docs \
    --lang javascript \
    --output /local \
    --additional-properties usePromises=true,useES6=true,emitModelMethods=true,projectName='@scope/my-project',projectDescription='Some description...'

Steps to reproduce

1. Run the above docker command (be sure to pass it a Swagger spec that both exists and is valid).
2. Run npm test.
3. Observe the error that is thrown.

Suggest a fix/enhancement

Modify https://github.com/swagger-api/swagger-codegen/blob/master/modules/swagger-codegen/src/main/resources/Javascript/model_test.mustache#L11

I'll try and get a PR going, just wanted to solicit some quick feedback.

Inspect modules/swagger-codegen/src/main/resources/Javascript/model_test.mustache at the referenced line, then reproduce the issue with the Docker generation command and run npm test. Done means generated tests for a scoped projectName parse and pass without the @ symbol causing invalid JavaScript syntax.