Utilities

Problem

You want to ensure your code has no side-effects.

Solution 1: Deny Property Access

denyPropertyAccess<T>(instance: T, property: string)

Use this if you want to verify, that a specified property will not get accessed during the test:

some.spec.ts

import { denyPropertyAccess } from "mockzilla";

test("modifiedDate will not be touched", () => {
    const myInstance = new MyClass();
    denyPropertyAccess(myInstance, "modifiedDate");
    myInstance.run();
    // If we got here, it means modifiedDate was not touched!
});

Solution 2: Whitelist Property Access

whitelistPropertyAccess(instance: any, ...whitelist: string[])

This can be used to call denyPropertyAccess on all properties except the ones in the whitelist:

import { whitelistPropertyAccess } from "mockzilla";

test("only tasks and showNotifiations may be touched", () => {
    const myInstance = new MyClass();
    whitelistPropertyAccess(myInstance, "run", "tasks", "showNotification");
    myInstance.run();
    // If we got here, it means no other properties than the ones specified above have been touched!
});