Convert tag cloud, vega and table tests to jest

[flash1293]

The tag cloud, vega and data table tests are currently using karma, angular mocking, visual diffs and require a real browser environment. To convert them to jest, multiple pieces have to be completed

Validate svg instead of rendered canvas

These tests have to be replaced by snapshot tests validating the svg tree instead of the rendered canvas. This has the additional benefit of being more stable than pixel comparisons (because of different fonts, ...)

For tag cloud, the following patching of jsdom apis tricks the rendering component into thinking there is enough space to layout the elements (the layouting itself happens within d3 and doesn't require a real dom):

      Object.defineProperties(window.HTMLElement.prototype, {
        offsetHeight: {
          get: function() { return 512; }
        },
        offsetWidth: {
          get: function() { return 512; }
        },
      });
      Object.defineProperties(window.SVGElement.prototype, {
        getBBox: {
          get: () => function () {
            return {
              x: 0,
              y: 0,
              width: 512,
              height: 512,
            }
          }
        }});

For vega specs, adding

      autosize: { type: 'none' }
      width: 512
      height: 512
      config: { kibana: { renderer: 'svg' }}

to the spec sets the size of the rendering area and makes sure an svg tree is created.

Get rid of ngMock and contracts of other plugins

• ngMock is not required as angular isn't used within the visualizations
• No real Vis object is needed to render successfully, the necessary parts can be simulated by an inline mock
• The visualization does not have to be registered - all integrations createBaseVisualization of the visualizations plugin is setting up should be simulated by inline mocks if necessary

Get rid of hson files

Vega stores the test specs in hson files. In the new platform there is no raw loader - convert hson files to json, import json directly and pass it into the visualizations via JSON.stringify.

Add smoke test with FTR and percy

To test the wider integration, add a functional test runner test for tag cloud and vega doing a simple visual regression test via percy.

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)

[flash1293]

Closed by linked PRs