Merge pull request #6 from fac20/fetch-helper

test for fetchHelper + test passes

src/modules/fetch-helper.js

@@ -1,7 +1,7 @@
 const API_BASE = "https://fishbase.ropensci.org/";
 
 const fetchHelper = (url) => {
-  fetch(`${API_BASE}${url}`).then(checkResponse);
+  return fetch(`${API_BASE}${url}`).then(checkResponse);
 };
 
 const checkResponse = (res) => {

src/modules/fetch-helper.test.js

@@ -0,0 +1,18 @@
+import { fetchHelper } from "./fetch-helper";
+
+const mockResponse = { data: [{ SpeciesRefNo: 168 }] };
+global.fetch = jest // any time fetch runs, we're going to replace it with the anonymous func @ line 6
+  .fn()
+  .mockImplementation(() => {
+    return Promise.resolve({
+      // promise will resolve into lines 8 + 9
+      ok: true,
+      json: () => Promise.resolve(mockResponse),
+    });
+  });
+
+test("Get input and receive a response", () => {
+  return fetchHelper("species/132").then((res) => {
+    expect(res.data[0].SpeciesRefNo).toEqual(168);
+  });
+});