dynamic-scope.test.js

const { context } = require('testim'); /* Magic */

describe('my dynamic scope test', () => {
    let something = 'anything';// Can't access this variable, we can only use context

    function addFoo() {
        let name = context.getVar('name') || '';
        name = name + 'foo';
        context.setVar('name', name);
    }
    function addBar() {
        let name = context.getVar('name') || '';
        name = name + 'bar';
        context.setVar('name', name);
        addFoo(); // This does affect the name in current scope
    }

    it('should fail', () => {
        addBar();
        let name = context.getVar('name');
        expect(name).toBe('bar'); // Name is actually foobar
    });
});

static-scope.test.js

describe('my test', () => {
    let something = 'anything';// Can access this variable

    function addFoo() {
        let name = '';
        name = name + 'foo';
        return name;
    }
    function addBar() {
        let name = '';
        name = name + 'bar';
        addFoo(); // This doesn't affect the name in current scope
        return name;
    }

    it('should pass', () => {
        expect(addBar()).toBe('bar');
    });
});