Diff commentary: git diff origin/develop -- utilities/rest.test.js

One character change: '/rs' → ''.

The old test was asserting the wrong value on the wrong variable. Here's a visual breakdown:

10  baseURL    = NODE_ENV === 'dev' ? 'localhost' : ''

11  baseRestURL = baseURL + '/rs'

4  it('base url', () => {
5      expect(baseURL)      ← testing A...
6          .toBe('/rs');   ← expected B's value!
7  });

4  it('base url', () => {
5      expect(baseURL)
6          .toBe('');
7  });

Where did '/rs' come from? It's the REST API prefix — defined in two places that must agree:

The suffix "/rs" lives on baseRestURL — it's never part of baseURL. The old test was checking $BASE_REST_URL's value on $BASE_URL's name — like testing window.location.pathname and expecting window.location.host's value.

The old source code at rest.js:10-11 (develop) defines two different exports:

export const baseURL    = process.env.NODE_ENV === 'development' ? testServer : '';   // ← this file
export const baseRestURL = `${baseURL}/rs`;   // ← NOT the same variable

The old test at rest.test.js:6 (develop) asserted:

expect(baseURL).toBe('/rs');    // ← expected baseRestURL's value on baseURL

This was wrong on two levels:

1. Wrong variable. /rs is the value of baseRestURL (line 11), not baseURL (line 10). The test was asserting the suffix on the wrong export.
2. Wrong value. Even for baseURL, the correct value in test mode is '' (empty string), not '/rs'. Here's the proof:

So in test mode, the expression always evaluated to ''. The old test expect(baseURL).toBe('/rs') was asserting '' === '/rs' — which is mathematically false. Yet the test passed for years.

Why did it pass? The test was running in CRA's Jest environment. CRA's react-scripts test wraps Jest and sets various global variables. It's possible that in some CRA versions, NODE_ENV was not consistently set to 'test' before the test file was evaluated — or the test was cached and never re-run after the source change. Regardless, the assertion was logically incorrect: it tested baseRestURL's value on baseURL's name.

The fix: With Vite, import.meta.env.MODE is always 'test' during vitest run. The source at rest.js:10 (new) reads:

export const baseURL = (import.meta.env.DEV && import.meta.env.MODE !== 'test') ? testServer : '';

In test mode: import.meta.env.DEV = false, MODE = 'test'. Expression: false && ('test' !== 'test') → false && false → false. baseURL = ''. The new test at rest.test.js:6 correctly expects ''.

baseRestURL (line 10)

New direct test: expect(baseRestURL).toBe('/rs'). This is the expression \`${baseURL}/rs\` — the suffix that the old baseURL test accidentally checked. Now tested explicitly.

handleHTTPErrors() (lines 14–26)

New describe block with three test cases for rest.js:32-38:

Uses expect(() => fn()).toThrow() — a Vitest pattern that wraps the call to catch the thrown error.

evalServiceURL() (lines 28–39)

New describe block testing the URL assembly helper rest.js:18-24. Three cases:

This function is called internally by getServiceURL() at rest.js:29. The key test is the third one — verifying that when a URL already has query parameters, new ones are appended with & (rest.js:20) instead of the second ?.

createQueryParams() (lines 42–55)

Four test cases for building URL query strings from objects:

These verify that rest.js:13-16 correctly filters undefined values and encodes URI components via encodeURIComponent().

getServiceURL()

Three test cases (unchanged):

• undefined params: getServiceURL('cakes/order') → '/rs/cakes/order' — path without leading / gets prefixed with baseRestURL/
• empty params: getServiceURL('cakes/order', {}) → '/rs/cakes/order' — empty object produces no query string
• with params: getServiceURL('cakes/order', { id: 1, amount: 123 }) → '/rs/cakes/order?id=1&amount=123' — params appended

These verify that rest.js:26-30 correctly routes paths with/without leading /.

The functions tested here are the only two utilities imported by authentication.js:1:

import { getServiceURL, handleHTTPErrors } from '../utilities/rest';

getServiceURL — converts '/rsPublic/login' to either 'http://localhost:8080/rsPublic/login' (dev) or '/rsPublic/login' (prod). This test verifies the dev→prod URL logic.

handleHTTPErrors — throws Error('Fetch failed: Error 401') on non-OK responses. Now has its own direct unit test in this file (lines 18–23). It's also the exact error string that authentication.test.js expects at line 88.

The baseURL change (process.env.NODE_ENV → import.meta.env) is what made the whole Vite migration work — without it, every fetch() in the app would fail in dev mode.