Cannot execute tests when babel does not transpile 'let' keyword

[janmisek]

Happening on 2.3.0-beta.1 in chromium 47

I am getting following exception when executing tests in case babel transpilation of 'let' keyword is disabled.

Uncaught SyntaxError: Block-scoped declarations (let, const, function, class) not yet supported outside strict mode

My ember-cli-build.js config for babel

        babel: {
            comments: false,
            optional: [
                //"es7.asyncFunctions"
                //"es7.functionBind"
            ],
            blacklist: [
                'es6.templateLiterals',
                'es6.blockScoping',
                'es6.constants'
            ]
        },

Generally problem is that each non jshint module included in compiled tests.js is missing 'use strict' statement

[janmisek]

I have traced down issue to the https://github.com/babel/ember-cli-babel/blob/cb4c2e763eb2fdb96654957ee2578912f88a8265/index.js#L93 where useStrict is blacklisted from babel with comment Ember-CLI inserts its own 'use strict' directive. But for tests tree (tests.js) this ember-cli strict mode is not used

[janmisek]

What about use lib/broccoli/test-prefix.js with use strict content to be used same way for tests.

[stefanpenner]

@nathanhammond i think the use-strict trick you added needs to also prepend to the test file.

[rwjblue]

Ya, agreed. Possibly also to test-support.js.

[nathanhammond]

@rwjblue Can't turn it on for test-support.js since both Ember and QUnit do things where they assume that this is set inside of an IIFE. Not a problem in this case as no user code ends up inside of test-support.js.

@janmisek Thanks for reporting, sorry to take so long on addressing. 😄