A Deno module to mock fetch().
import { mockFetch, unMockFetch } from "https://deno.land/x/metch/mod.ts";
import { assertEquals } from "https://deno.land/std@0.90.0/testing/asserts.ts";
Deno.test("mocks fetch() as expected", async () => {
const request1 = new Request("https://example.com");
const expectedResponse1 = new Response("<html> example.com </html>", {
status: 200,
headers: {
"content-type": "text/html",
},
});
const request2 = new Request("https://example.rest");
const expectedResponse2 = new Response(
JSON.stringify({ message: "example" }),
{
status: 200,
headers: {
"content-type": "text/html",
},
},
);
// Pass a request object and a response object which
// will be used to respond to fetch().
await mockFetch(request1, expectedResponse1.clone());
// Call again to mock more requests.
await mockFetch(request2, expectedResponse2.clone());
const response1 = await fetch(request1);
const response2 = await fetch(request2);
assertEquals(response1.status, expectedResponse1.status);
assertEquals(await response1.text(), await expectedResponse1.text());
assertEquals(
response1.headers.get("content-type"),
expectedResponse1.headers.get("content-type"),
);
assertEquals(response2.status, expectedResponse2.status);
assertEquals(await response2.text(), await expectedResponse2.text());
assertEquals(
response2.headers.get("content-type"),
expectedResponse2.headers.get("content-type"),
);
// Restore original fetch().
unMockFetch();
});