Testing interaction with html and JavaScript using Jasmine is wrong?

JavaScript code has some interactions with html like this example:

function retornaListaDeItens(argument) {
  return document.getElementsByClassName(argument);
}

I use the return of this function to perform operations in JavaScript, performing the unit test using Jasmine I ended up coming across the following scenario of doubts:

1. Is it wrong to perform the test of this function?

2. Is it possible to simulate my html to perform tests that interact with it?

A test structure uses the SpecRunner file itself.Jasmine's html and has no contact with the html where it has the list of items to be returned in this example, this ends up making unit testing difficult.

The structure is more or less like this:

app
  lib
  --bootstrap
  --jasmine
  src
  --css
  --js
    --teste.js
  test
  --testeSpec.js
  index.html

The idea of testing is like this:

  it("retorno de lista de itens não deve ser vazio", function() {
    var item = "item";
    var list = retornaListaDeItens(item);
    console.log(list.length);
    expect(list).not.toBeLessThan(0);
  });