Added jest and converted all tests but those that deal with Leaflet. Need to figure out

assets/.eslintrc

assets/package-lock.json

assets/package.json

assets/src/scripts/ajax.test.js

assets/src/scripts/d3-rendering/accessibility.test.js

assets/src/scripts/d3-rendering/alerts.test.js

assets/src/scripts/d3-rendering/axes.test.js

assets/src/scripts/d3-rendering/cursor-slider.testjs

assets/src/scripts/d3-rendering/data-masks.test.js

assets/src/scripts/d3-rendering/graph-tooltip.test.js

assets/src/scripts/d3-rendering/info-tooltip.test.js

assets/src/scripts/d3-rendering/legend.test.js

assets/src/scripts/d3-rendering/loading-indicator.test.js

assets/src/scripts/d3-rendering/markers.js

assets/src/scripts/d3-rendering/markers.test.js

assets/src/scripts/d3-rendering/tick-marks.test.js

assets/src/scripts/lib/d3-redux.test.js

...ion/components/daily-value-hydrograph/graph-brush.test.js

.../components/daily-value-hydrograph/graph-controls.test.js

...-location/components/daily-value-hydrograph/index.test.js