CODEWITHSUNDEEP
unit-testingtypescriptjasmine
Kraken
Kraken

Reputation: 39

How to write unit test in jasmine and test method without calling other methods?

For example, this class:

export class List<T> {
    private _count: number;
    private _items: Array<T>;

    constructor() {
        this._count = 0;
        this._items = [];
    }

    get(index: number) {
        return this._items[index];
    }

    add(item: T) {
        this._items[this._count] = item;
        this._count++;
    }
}

This unit test in jasmine:

import { List } from './list';

describe( 'List', () => {

    let testList: List<string>;

    beforeEach(() => {
        testList = new List<string>();
    } );

    it( 'get() method works', () => {
        //how to test get() method without calling add() method?
        testList.add( "string1" );
        testList.add( "string2" );
        testList.add( "string3" );

        let s1: string = testList.get( 0 );
        let s2: string = testList.get( 1 );
        let s3: string = testList.get( 2 );

        expect( s1 ).toBe( "string1" );
        expect( s2 ).toBe( "string2" );
        expect( s3 ).toBe( "string3" );
    } );
}

I think, this is not unit test, but integration test, so how to write right unit test? I look at mock, but I don't know, how to use it in this case.

Upvotes: 0

Views: 64

Answers (1)

slesh
slesh

Reputation: 2017

As the first option, you can fix state before testing a get method, i.e. add a check if the list is empty before adding items. As a second option, you can try to add a constructor with initial items, and a test for both empty constructor and constructor with items. Then you can rework your test without calling an add method.

But I think it's not so important because in any case, you will call other methods. Unit testing suggests isolating from other components like HTTP, database and so on.

Upvotes: 1

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