as seen on travis

 PASS  webpack/assets/javascripts/react_app/components/BreadcrumbBar/components/BreadcrumbSwitcherPopover.test.js
  BreadcrumbSwitcherPopover
    ✓ render loading state (2ms)
    ✓ render resources list (4ms)
    ✓ render resources list with pagination (2ms)
    ✓ render resources list with a search query (2ms)
console.error node_modules/fbjs/lib/warning.js:33
    Warning: Failed prop type: The prop `substring` is marked as required in `SubstringWrapper`, but its value is `undefined`.
        in SubstringWrapper