node.js - Using mocha with TDD interface, ReferenceError -

i trying unittesting node via mocha , chai. familiar python's built in unittest framework, using mocha's tdd interface, , chai's tdd style assertions.

the issue running mocha's tdd setup function. running, variables declare within undefined within tests.

here code:

test.js

var assert = require('chai').assert;  suite('testing unit testing === testception', function(){    setup(function(){     // setup function, y u no define variables?     // these work if move them individual tests,     // not want :(     var        foo = 'bar';   });    suite('chai tdd style assertions should work', function(){     test('true === true', function(){       var blaz = true;       assert.istrue(blaz,'blaz true');     });   });    suite('chai assertions using setup', function(){     test('variables declared within setup should accessible',function(done){       assert.typeof(foo, 'string', 'foo string');       assert.lengthof(foo, 3, 'foo`s value has length of 3');     });   }); }); 

which generates following error:

✖ 1 of 2 tests failed:     1) testing unit testing === testception chai assertions using setup variables declared within  setup should accessible:          referenceerror: foo not defined 

you're declaring foo in scope inaccessible other tests.

suite('testing unit testing === testception', function(){    var foo; // declare in scope tests can access.    setup(function(){     foo = 'bar'; // make changes/instantiations here   });    suite('this test able use foo', function(){     test('foo not undefined', function(){       assert.isdefined(foo, 'foo should have been defined.');     });   }); });