[js-testing] type checking for dates.js (#2893)

* tests for dates.js

* linting

* test fduration output

* ignore warnings in code climate

* use eslint-2 otherwise defaults to eslint-3

* test eslint 1

* remove channel rule

* disable checks

* checks for eslint engine

superset/assets/spec/javascripts/modules/dates_spec.js

@@ -0,0 +1,85 @@
+import { it, describe } from 'mocha';
+import { expect } from 'chai';
+import {
+  tickMultiFormat,
+  formatDate,
+  timeFormatFactory,
+  fDuration,
+  now,
+  epochTimeXHoursAgo,
+  epochTimeXDaysAgo,
+  epochTimeXYearsAgo,
+ } from '../../../javascripts/modules/dates';
+
+describe('tickMultiFormat', () => {
+  it('is a function', () => {
+    assert.isFunction(tickMultiFormat);
+  });
+});
+
+describe('formatDate', () => {
+  it('is a function', () => {
+    assert.isFunction(formatDate);
+  });
+});
+
+describe('timeFormatFactory', () => {
+  it('is a function', () => {
+    assert.isFunction(timeFormatFactory);
+  });
+});
+
+describe('fDuration', () => {
+  it('is a function', () => {
+    assert.isFunction(fDuration);
+  });
+
+  it('returns a string', () => {
+    expect(fDuration(new Date(), new Date())).to.be.a('string');
+  });
+
+  it('returns the expected output', () => {
+    const output = fDuration('1496293608897', '1496293623406');
+    expect(output).to.equal('00:00:14.50');
+  });
+});
+
+describe('now', () => {
+  it('is a function', () => {
+    assert.isFunction(now);
+  });
+
+  it('returns a number', () => {
+    expect(now()).to.be.a('number');
+  });
+});
+
+describe('epochTimeXHoursAgo', () => {
+  it('is a function', () => {
+    assert.isFunction(epochTimeXHoursAgo);
+  });
+
+  it('returns a number', () => {
+    expect(epochTimeXHoursAgo(1)).to.be.a('number');
+  });
+});
+
+describe('epochTimeXDaysAgo', () => {
+  it('is a function', () => {
+    assert.isFunction(epochTimeXDaysAgo);
+  });
+
+  it('returns a number', () => {
+    expect(epochTimeXDaysAgo(1)).to.be.a('number');
+  });
+});
+
+describe('epochTimeXYearsAgo', () => {
+  it('is a function', () => {
+    assert.isFunction(epochTimeXYearsAgo);
+  });
+
+  it('returns a number', () => {
+    expect(epochTimeXYearsAgo(1)).to.be.a('number');
+  });
+});