chore: Move FetchUtil to util folder.

test/unit/util/FetchUtil.test.ts

@@ -0,0 +1,38 @@
+import fetch from '@rdfjs/fetch';
+import type { DatasetResponse } from '@rdfjs/fetch-lite';
+import type { Dataset } from 'rdf-js';
+import { fetchDataset } from '../../../src/util/FetchUtil';
+
+jest.mock('@rdfjs/fetch');
+
+describe('FetchUtil', (): void => {
+  describe('#fetchDataset', (): void => {
+    const fetchMock: jest.Mock = fetch as any;
+    const url = 'http://test.com/foo';
+    let datasetResponse: DatasetResponse<Dataset>;
+    const dataset: Dataset = {} as any;
+
+    beforeEach(async(): Promise<void> => {
+      datasetResponse = {
+        dataset: jest.fn().mockReturnValue(dataset),
+      } as any;
+
+      fetchMock.mockResolvedValue(datasetResponse);
+    });
+
+    it('errors if there was an issue fetching.', async(): Promise<void> => {
+      fetchMock.mockRejectedValueOnce(new Error('Invalid webId!'));
+      await expect(fetchDataset(url)).rejects.toThrow(`Cannot fetch ${url}`);
+      expect(fetchMock).toHaveBeenCalledWith(url);
+    });
+
+    it('errors if there was an issue parsing the returned RDF.', async(): Promise<void> => {
+      (datasetResponse.dataset as jest.Mock).mockRejectedValueOnce(new Error('Invalid RDF!'));
+      await expect(fetchDataset(url)).rejects.toThrow(`Cannot fetch ${url}`);
+    });
+
+    it('returns the resulting Dataset.', async(): Promise<void> => {
+      await expect(fetchDataset(url)).resolves.toBe(dataset);
+    });
+  });
+});