Add test to ensure components can be imported

Add a failing test that tries to render every component using a different base path for Nunjucks - any imports that assume a particular base path will then throw exceptions.

src/components/all.test.js

@@ -0,0 +1,27 @@
+/* eslint-env jest */
+
+const { allComponents } = require('../../lib/file-helper')
+
+const configPaths = require('../../config/paths.json')
+
+// We can't use the render function from jest-helpers, because we need control
+// over the nunjucks environment.
+const nunjucks = require('nunjucks')
+
+describe('When nunjucks is configured with a different base path', () => {
+  beforeAll(() => {
+    // Create a new Nunjucks environment that uses the src directory as its
+    // base path, rather than the components folder itself
+    nunjucks.configure(configPaths.src)
+  })
+
+  allComponents.forEach((component) => {
+    describe(`the ${component} component`, () => {
+      it('can be rendered without erroring', () => {
+        expect(() => {
+          nunjucks.render(`components/${component}/template.njk`, {})
+        }).not.toThrow()
+      })
+    })
+  })
+})