Use the spyOn utility to track method calls with Bun's test runner.
import { test, expect, spyOn } from "bun:test";
const leo = {
name: "Leonardo",
sayHi(thing: string) {
console.log(`Sup I'm ${this.name} and I like ${thing}`);
},
};
const spy = spyOn(leo, "sayHi");
Once the spy is created, it can be used to write expect assertions relating to method calls.
import { test, expect, spyOn } from "bun:test";
const leo = {
name: "Leonardo",
sayHi(thing: string) {
console.log(`Sup I'm ${this.name} and I like ${thing}`);
},
};
const spy = spyOn(leo, "sayHi");
test("turtles", ()=>{
expect(spy).toHaveBeenCalledTimes(0);
leo.sayHi("pizza");
expect(spy).toHaveBeenCalledTimes(1);
expect(spy.mock.calls).toEqual([[ "pizza" ]]);
})See Docs > Test Runner > Mocks for complete documentation on mocking with the Bun test runner.