pyscript/pyscriptjs/tests/unit/fetch.test.ts

import { describe, it, expect, jest } from '@jest/globals'
import { FetchError, ErrorCode } from "../../src/exceptions"
import { robustFetch } from "../../src/fetch"
import { Response } from 'node-fetch';

describe("robustFetch", () => {

  it("should return a response object", async () => {
    global.fetch = jest.fn(() => (Promise.resolve(new Response(status="200", "Hello World"))));

    const response = await robustFetch("https://pyscript.net");
    expect(response).toBeInstanceOf(Response);
    expect(response.status).toBe(200);
  })

  it('receiving a 404 when fetching should throw FetchError with the right errorCode', async () => {
    global.fetch = jest.fn(() => (Promise.resolve(new Response("Not Found", {status: 404}))));

    const url = "https://pyscript.net/non-existent-page"
    const expectedError = new FetchError(
      ErrorCode.FETCH_NOT_FOUND_ERROR,
      `Fetching from URL ${url} failed with error 404 (Not Found). ` +
      `Are your filename and path correct?`
    )

    expect(() => robustFetch(url)).rejects.toThrow(expectedError);
  })

  it('receiving a 401 when fetching should throw FetchError with the right errorCode', async () => {
    global.fetch = jest.fn(() => (Promise.resolve(new Response("", {status: 401}))));

    const url = "https://pyscript.net/protected-page"
    const expectedError = new FetchError(
      ErrorCode.FETCH_UNAUTHORIZED_ERROR,
      `Fetching from URL ${url} failed with error 401 (Unauthorized). ` +
      `Are your filename and path correct?`
    )

    expect(() => robustFetch(url)).rejects.toThrow(expectedError);
  })

  it('receiving a 403 when fetching should throw FetchError with the right errorCode', async () => {
    global.fetch = jest.fn(() => (Promise.resolve(new Response("", {status: 403}))));

    const url = "https://pyscript.net/secret-page"
    const expectedError = new FetchError(
      ErrorCode.FETCH_FORBIDDEN_ERROR,
      `Fetching from URL ${url} failed with error 403 (Forbidden). ` +
      `Are your filename and path correct?`
    )

    expect(() => robustFetch(url)).rejects.toThrow(expectedError);
  })

  it('receiving a 500 when fetching should throw FetchError with the right errorCode', async () => {
    global.fetch = jest.fn(() => (Promise.resolve(new Response("Not Found", {status: 500}))));

    const url = "https://pyscript.net/protected-page"
    const expectedError = new FetchError(
      ErrorCode.FETCH_SERVER_ERROR,
      `Fetching from URL ${url} failed with error 500 (Internal Server Error). ` +
      `Are your filename and path correct?`
    )

    expect(() => robustFetch(url)).rejects.toThrow(expectedError);
  })

  it('receiving a 503 when fetching should throw FetchError with the right errorCode', async () => {
    global.fetch = jest.fn(() => (Promise.resolve(new Response("Not Found", {status: 503}))));

    const url = "https://pyscript.net/protected-page"
    const expectedError = new FetchError(
      ErrorCode.FETCH_UNAVAILABLE_ERROR,
      `Fetching from URL ${url} failed with error 503 (Service Unavailable). ` +
      `Are your filename and path correct?`
    )

    expect(() => robustFetch(url)).rejects.toThrow(expectedError);
  })

  it('handle TypeError when using a bad url', async () => {
    global.fetch = jest.fn(() => (Promise.reject(new TypeError("Failed to fetch"))));

    const url = "https://pyscript.net/protected-page"
    const expectedError = new FetchError(
      ErrorCode.FETCH_ERROR,
      `Fetching from URL ${url} failed with error 'Failed to fetch'. Are your filename and path correct?`
    )

    expect(() => robustFetch(url)).rejects.toThrow(expectedError);
   })

   it('handle failed to fetch when using local file', async () => {
    global.fetch = jest.fn(() => (Promise.reject(new TypeError("Failed to fetch"))));

    const url = "./my-awesome-pyscript.py"

    const expectedError = new FetchError(
      ErrorCode.FETCH_ERROR,
      `PyScript: Access to local files
        (using "Paths:" in <py-config>)
        is not available when directly opening a HTML file;
        you must use a webserver to serve the additional files.
        See <a style="text-decoration: underline;" href="https://github.com/pyscript/pyscript/issues/257#issuecomment-1119595062">this reference</a>
        on starting a simple webserver with Python.
            `
    )

    expect(() => robustFetch(url)).rejects.toThrow(expectedError);
   })
});