Test boot's browser-extension-utils

src/boot/browser-extension-utils.js

 /**
- * Tries to get the extension ID which is running this script, or undefined if
- * this script is not being run by the browser extension
+ * Returns the extension ID which is running this script, or undefined if this
+ * script is not being run by the browser extension.
  *
  * @param {Window} window_
  * @return {string | undefined}
@@ -11,7 +11,7 @@ export function getExtensionId(window_ = window) {
 
 /**
  * Verifies if there's a config script in the document that was generated by a
- * specific extension
+ * specific browser extension.
  *
  * @param {string} extensionId
  * @param {Document} document_

src/boot/test/browser-extension-utils-test.js

+import { getExtensionId, hasExtensionConfig } from '../browser-extension-utils';
+
+describe('browser-extension-utils', () => {
+  describe('getExtensionId', () => {
+    [
+      { window: {}, expectedId: undefined },
+      {
+        window: {
+          chrome: {},
+        },
+        expectedId: undefined,
+      },
+      {
+        window: {
+          chrome: {
+            runtime: {},
+          },
+        },
+        expectedId: undefined,
+      },
+      {
+        window: {
+          chrome: {
+            runtime: { id: 'hypothesisId' },
+          },
+        },
+        expectedId: 'hypothesisId',
+      },
+    ].forEach(({ window, expectedId }) => {
+      it('returns the extension ID only when running in the scope of a browser extension', () => {
+        assert.equal(getExtensionId(window), expectedId);
+      });
+    });
+  });
+
+  describe('hasExtensionConfig', () => {
+    let fakeDocument;
+
+    beforeEach(() => {
+      fakeDocument = {
+        querySelector: sinon.stub(),
+      };
+    });
+
+    [
+      { element: null, configExists: false },
+      { element: {}, configExists: true },
+    ].forEach(({ element, configExists }) => {
+      it('returns proper result if the config script was found', () => {
+        fakeDocument.querySelector.returns(element);
+
+        assert.equal(
+          hasExtensionConfig('hypothesisId', fakeDocument),
+          configExists
+        );
+        assert.calledWith(
+          fakeDocument.querySelector,
+          sinon.match('hypothesisId')
+        );
+      });
+    });
+  });
+});