Add a test for when d3 isn't available.
MODIFY
tests/cases/renderers.js
tests/cases/renderers.js
@@ -71,6 +71,12 @@ describe('renderers', function () {
expect(geo.checkRenderer('d3')).toBe('d3');
+ var oldd3 = __webpack_modules__[require.resolveWeak('d3')]; // eslint-disable-line
+ __webpack_modules__[require.resolveWeak('d3')] = null; // eslint-disable-line
+ expect(geo.checkRenderer('d3')).toBe(null);
+ __webpack_modules__[require.resolveWeak('d3')] = oldd3; // eslint-disable-line
+ expect(geo.checkRenderer('d3')).toBe('d3');
+
mockVGLRenderer(false);
expect(geo.checkRenderer('vgl')).toBe(null);
restoreVGLRenderer();

Add a test for when d3 isn't available.