How to properly test private methods in Angular/TypeScript using Jasmine?

Hello everyone! I'm new to Angular and TypeScript, and I'm having a problem writing unit tests for private methods. I have a service that performs complex calculations, and I extracted some logic into a private method for better readability. Here's an example of my code: ```typescript import { Injectable } from '@angular/core'; @Injectable({ providedIn: 'root' }) export class CalculationService { public calculateTotal(items: number[]): number { const filtered = this.filterInvalidItems(items); return filtered.reduce((sum, item) => sum + item, 0); } private filterInvalidItems(items: number[]): number[] { return items.filter(item => item > 0 && item < 1000); } } ``` When I try to write a test for `filterInvalidItems` using Jasmine, I get an error