你们能帮我在 jasmine 中为下面这段代码编写测试用例吗

Question

Here I've two arrays and i need to insert the objects in array from another array. Below is my code

scope.newBal=[];
scope.actualBal=[
{date:2020-02-04,
bal:100.0},
{date:2020-02-09,
bal:530.0},
{date:2020-02-16,
bal:190.0},
{date:2020-02-23,
bal:4560.0}];

scope.newBal=scope.actualBal.filter(b => b.date.isAfter(startDate));

In the above code I had stored the objects in *newBal* array, after the startDate from *actualBal* array. 
So in my *newBal* array I've the below data:-
scope.newBal=[{date:2020-02-16, bal:190.0}, {date:2020-02-23, bal:4560.0}];

But i'm unable to write the test cases of above code in jasmine, So can you guys help me in this.

Answer 1

To write unit test cases in jasmine for above piece of code first of all initialise associated variables with dummy data

• startDate with any particular date.
• scope.newBal as empty array
• scope.actualBal array with two objects, one having date prior to startDate and another post startDate

Then call the function which is encapsulating above piece of code. After this you can make following assertions

• scope.newBal array has one element which is object with date post startDate .
• scope.actualBal has not been changed and is same as initialised before.

Here is the code snippet implementing above steps -

it('scope.myFunction() should copy all objects from scope.actualBal post startDate to scope.newBal', function() {
  // setup - initialise scope variables
  scope.startDate = new Date(2020, 03, 26); // year, 0-indexed month, date;
  scope.newBal = [];
  var balance_prior_date = {date:new Date(2020, 03, 25), bal:100.0};
  var balance_post_date = {date:new Date(2020, 03, 27), bal: 50.0};
  scope.actualBal = [balance_prior_date, balance_post_date];

  // action - call encapsulating function
  scope.myFunction();

  // assert
  // only relevant object shall be copied to newBal array
  expect(scope.newBal.length).toBe(1);
  expect(scope.newBal).toContain(balance_post_date);
  // actualBal array should remain as it is
  expect(scope.actualBal.length).toBe(2);
})