[Unit testing RxJS] Testing Observables with Subscribe and assert Parttern
and with Rxjs Testing unit assert Observables
2023-09-14 09:00:45 时间
const { of } = require("rxjs");
const { mergeMap, map, delay, catchError } = require("rxjs/operators");
describe("subscribe & assert testing in RxJS", () => {
it("should compare each emitted value", () => {
const source$ = of(1, 2, 3);
const final$ = source$.pipe(map((val) => val * 10));
const expected = [10, 20, 30];
let index = 0;
final$.subscribe((val) => {
expect(val).toEqual(expected[index]);
index++;
});
});
// recommend to run this kind of test in marable testing
// this test case only test val emitted
// but not the time
// would be better to test exp. after 1 second, "Set" was emitted
it("should let you test async operations with done callback", (done) => {
const source$ = of("Ready", "Set", "Go").pipe(
mergeMap((message, index) => of(message).pipe(delay(index * 1000)))
);
const expected = ["Ready", "Set", "Go"];
let index = 0;
source$.subscribe(
(val) => {
expect(val).toEqual(expected[index]);
index++;
},
null,
done // tell jasmine, async function has completed
);
});
it("should let you test erros and error message", () => {
const source$ = of(
{ firstName: "Joe", lastName: "Smith" },
undefined // trigger error as an invalid user
).pipe(
map(({ firstName, lastName }) => `${firstName} ${lastName}`),
catchError(() => {
throw new Error("Invalid user!");
})
);
const expected = ["Joe Smith", new Error("Invalid user!")];
let actual = [];
source$.subscribe({
next: (val) => {
actual.push(val);
},
error: (error) => {
actual.push(error);
expect(actual).toEqual(expected);
},
});
});
});
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