[Explore] Streamlined metric definitions for SQLA and Druid (#4663)

* adding streamlined metric editing

* addressing lint issues on new metrics control

* enabling druid

superset/assets/spec/javascripts/explore/components/AdhocMetricEditPopoverTitle_spec.jsx

@@ -0,0 +1,48 @@
+/* eslint-disable no-unused-expressions */
+import React from 'react';
+import sinon from 'sinon';
+import { expect } from 'chai';
+import { describe, it } from 'mocha';
+import { shallow } from 'enzyme';
+import { OverlayTrigger } from 'react-bootstrap';
+
+import AdhocMetric from '../../../../javascripts/explore/AdhocMetric';
+import AdhocMetricEditPopoverTitle from '../../../../javascripts/explore/components/AdhocMetricEditPopoverTitle';
+import { AGGREGATES } from '../../../../javascripts/explore/constants';
+
+const columns = [
+  { type: 'VARCHAR(255)', column_name: 'source' },
+  { type: 'VARCHAR(255)', column_name: 'target' },
+  { type: 'DOUBLE', column_name: 'value' },
+];
+
+const sumValueAdhocMetric = new AdhocMetric({
+  column: columns[2],
+  aggregate: AGGREGATES.SUM,
+});
+
+function setup(overrides) {
+  const onChange = sinon.spy();
+  const props = {
+    adhocMetric: sumValueAdhocMetric,
+    onChange,
+    ...overrides,
+  };
+  const wrapper = shallow(<AdhocMetricEditPopoverTitle {...props} />);
+  return { wrapper, onChange };
+}
+
+describe('AdhocMetricEditPopoverTitle', () => {
+  it('renders an OverlayTrigger wrapper with the title', () => {
+    const { wrapper } = setup();
+    expect(wrapper.find(OverlayTrigger)).to.have.lengthOf(1);
+    expect(wrapper.find(OverlayTrigger).dive().text()).to.equal('My Metric\xa0');
+  });
+
+  it('transfers to edit mode when clicked', () => {
+    const { wrapper } = setup();
+    expect(wrapper.state('isEditable')).to.be.false;
+    wrapper.simulate('click');
+    expect(wrapper.state('isEditable')).to.be.true;
+  });
+});