[explore] viz type selector as modal (#2787)

* [explore] viz type selector as modal

* Addressing comments

* Adressing comments

superset/assets/spec/javascripts/explorev2/components/VizTypeControl_spec.jsx

@@ -0,0 +1,37 @@
+import React from 'react';
+import sinon from 'sinon';
+import { expect } from 'chai';
+import { describe, it, beforeEach } from 'mocha';
+import { shallow } from 'enzyme';
+import { Modal } from 'react-bootstrap';
+import VizTypeControl from '../../../../javascripts/explore/components/controls/VizTypeControl';
+
+const defaultProps = {
+  name: 'viz_type',
+  label: 'Visualization Type',
+  value: 'table',
+  onChange: sinon.spy(),
+};
+
+describe('VizTypeControl', () => {
+  let wrapper;
+
+  beforeEach(() => {
+    wrapper = shallow(<VizTypeControl {...defaultProps} />);
+  });
+
+  it('renders a Modal', () => {
+    expect(wrapper.find(Modal)).to.have.lengthOf(1);
+  });
+
+  it('calls onChange when toggled', () => {
+    const select = wrapper.find('.viztype-selector-container').first();
+    select.simulate('click');
+    expect(defaultProps.onChange.called).to.equal(true);
+  });
+  it('filters images based on text input', () => {
+    expect(wrapper.find('img').length).to.be.above(20);
+    wrapper.setState({ filter: 'time' });
+    expect(wrapper.find('img').length).to.be.below(10);
+  });
+});