test(fetch-error-handler): add test for 304 behaviour

Author: apaleslimghost

packages/fetch-error-handler/test/unit/lib/create-handler.spec.js

@@ -33,6 +33,19 @@ describe('@dotcom-reliability-kit/fetch-error-handler/lib/create-handler', () =>
 				expect(resolvedValue).toStrictEqual(mockResponse);
 			});
 
+			describe('when `response.ok` is `false` and `response.status` is 304', () => {
+				it('resolves with the response object', async () => {
+					expect.assertions(1);
+					try {
+						mockResponse.ok = false;
+						mockResponse.status = 304;
+						await fetchErrorHandler(mockResponse);
+					} catch (error) {
+						expect(resolvedValue).toStrictEqual(mockResponse);
+					}
+				});
+			});
+
 			describe('when `response.ok` is `false` and `response.status` is 400', () => {
 				it('rejects with an error describing the issue', async () => {
 					expect.assertions(3);
@@ -162,6 +175,19 @@ describe('@dotcom-reliability-kit/fetch-error-handler/lib/create-handler', () =>
 				expect(resolvedValue).toStrictEqual(mockResponse);
 			});
 
+			describe('when `response.ok` is `false` and `response.status` is 304', () => {
+				it('resolves with the response object', async () => {
+					expect.assertions(1);
+					try {
+						mockResponse.ok = false;
+						mockResponse.status = 304;
+						await fetchErrorHandler(Promise.resolve(mockResponse));
+					} catch (error) {
+						expect(resolvedValue).toStrictEqual(mockResponse);
+					}
+				});
+			});
+
 			describe('when `response.ok` is `false` and `response.status` is >= 400', () => {
 				it('rejects with an error', async () => {
 					expect.assertions(1);