Here is the test code

var list = new List([1, 2, 3, 4]);
var list2 = new List([5, 1]);

beforeAll(function () {
  spyOn(list.values, 'map').and.callThrough();

  list.map(plusOne);
});

it('Array.prototype.map()', function () {
  expect(list.values.map).not.toHaveBeenCalled();
});

This results in the following error 1) List must not call native Array function Array.prototype.map()   Message:
    Error: <toHaveBeenCalled> : Expected a spy, but got Function.
    Usage: expect(<spyObj>).toHaveBeenCalled()

  class List {
    constructor(clist = []) {
        this.values = clist;
    }
    map(f) {
        var temp = [];
        this.values.forEach((item, index) => {
                   temp.push(f(item));
                });
        this.values = temp;
        return this;
    }
}
module.exports = { List };

I do not think this is a unit test fail as such because I get the same message whether I call not.tohaveBeenCalled() or toHaveBeenCalled().

I am using node 8.9.4 and jasmine 2.8.0.

I believe the syntax is correct because when I run others code against these tests they pass. But my code causes this error.

My question is what does the above error mean? Regards,

Here is the test code

var list = new List([1, 2, 3, 4]);
var list2 = new List([5, 1]);

beforeAll(function () {
  spyOn(list.values, 'map').and.callThrough();

  list.map(plusOne);
});

it('Array.prototype.map()', function () {
  expect(list.values.map).not.toHaveBeenCalled();
});

This results in the following error 1) List must not call native Array function Array.prototype.map()   Message:
    Error: <toHaveBeenCalled> : Expected a spy, but got Function.
    Usage: expect(<spyObj>).toHaveBeenCalled()

  class List {
    constructor(clist = []) {
        this.values = clist;
    }
    map(f) {
        var temp = [];
        this.values.forEach((item, index) => {
                   temp.push(f(item));
                });
        this.values = temp;
        return this;
    }
}
module.exports = { List };

I do not think this is a unit test fail as such because I get the same message whether I call not.tohaveBeenCalled() or toHaveBeenCalled().

I am using node 8.9.4 and jasmine 2.8.0.

I believe the syntax is correct because when I run others code against these tests they pass. But my code causes this error.

My question is what does the above error mean? Regards,

• javascript
• jasmine

1 Answer 1

I just run the following test and it works on [email protected]

fit('Spy on map works', () => {
        let someArray = [1, 3, 5];
        spyOn(someArray, 'map').and.callThrough();
        someArray.map(function(r){ console.log(r); });
        expect(someArray.map).toHaveBeenCalled();
 });

You might want to run this example to know if it works in your tests.

As I said in the ment your list map method overrides the list.values with a new array. Hence, the spy is not there anymore. try something like:

someArray.forEach((item, index) => {
                   someArray[index] = f(item);
});

To explain what is happening:

//WORKS
 fit('Spy on map works', () => {
    let someArray = [1, 3, 5];
    spyOn(someArray, 'map').and.callThrough();
    someArray.forEach((item, index) => {
        someArray[index] = (item + '_t');
    });
    someArray.map(function(r){ console.log(r); });
    expect(someArray.map).toHaveBeenCalled();
});
//FAILS because array is another object.
fit('Spy on map fails', () => {
    let someArray = [1, 3, 5];
    spyOn(someArray, 'map').and.callThrough();

    let tempArray = [];
    someArray.forEach((item, index) => {
        tempArray.push(item + '_t');
    });
    someArray = tempArray;

    someArray.map(function(r){ console.log(r); });
    expect(someArray.map).toHaveBeenCalled();
});

However, you could just spy on prototype. Something like that:

 spyOn(Array.prototype, 'map').and.callThrough();

And then, your test should work.