Test: Array Processing
+ ++
This example shows how to use the ArrayAssert object, which
+ contains assertions designed to be used specifically with JavaScript Arrays and array-like objects.
Array Assertions
+ +This example uses the Y.ArrayAssert object to test methods on JavaScript's
+ built-in Array object. The intent of this example is to introduce Y.ArrayAssert and its methods
+ as an alternative to the generic methods available on Y.Assert.
The example begins by creating an example namespace and Y.Test.Case:
This TestCase has a setUp() method that creates an array for all the tests to use, as well as
+ a tearDown() method that deletes the array after each test has been executed. This array is used throughout
+ the tests as a base for array manipulations.
Testing push()
+The first test is testPush(), which tests the functionality of the Array object's push() method
+ (other methods hidden for simpicity):
The test begins by setting up a shortcut variables for Y.ArrayAssert, then pushes the value 6 onto
+ the data array (which was created by setUp()). Next, Y.ArrayAssert.isNotEmpty() determines if the
+ array has at least one item; this should definitely pass because the push() operation only adds values to the array. To determine
+ that the new value, 6, is in the array, Y.ArrayAssert.contains() is used. The first argument is the value to look for and the second
+ is the array to look in. To find out if the new value ended up where it should have (the last position, index 6), Y.ArrayAssert.indexOf()
+ is used, passing in the value to search for as the first argument, the array to search in as the second, and the index at which the value should
+ occur as the final argument. Since 6 was pushed onto the end of an array that already had 6 items, it should end up at index 6 (the length of the
+ array minus one). As a final test, Y.ArrayAssert.itemsAreEqual() is used to determine that all of the items in the array are in the
+ correct place. The first argument of this method is an array that has all of the values that should be in the array you're testing. This assertion
+ passes only when the values in both arrays match up (the values are equal and the positions are the same).
Testing pop()
+The next test is testPop(), which tests the functionality of the Array object's pop() method:
This test also starts out by creating some shortcut variables, for Y.Assert and Y.ArrayAssert. Next, the pop()
+ method is called, storing the returned item in value. Since pop() should only remove a single item, Y.ArrayAssert.isNotEmpty()
+ is called to ensure that only one item has been removed. After that, Y.Assert.areEqual() is called twice: once to check the
+ length of the array and once to confirm the value of the item that was removed from the array (which should be 5). The last assertion uses
+ Y.ArrayAssert.itemsAreSame(), which is similar to Y.ArrayAssert.itemsAreEqual() in that it compares values between two
+ arrays. The difference is that Y.ArrayAssert.itemsAreSame() uses strict equality (===) to compare values, ensuring that
+ no behind-the-scenes type conversions will occur (this makes Y.ArrayAssert.itemsAreSame() more useful for working with arrays of
+ objects).
Testing reverse()
+The next test is testReverse(), which tests the functionality of the Array object's reverse() method:
The testRemove() method is very simple, calling reverse() on the array and then testing the result. Since
+ every item in the array has changed, the changes can be tested by calling Y.ArrayAssert.itemsAreEqual() once (instead of
+ calling Y.ArrayAssert.indexOf() multiple times). The first argument is an array with all the values in the reverse order
+ of the array that was created in setUp(). When compared with the second argument, the newly reversed array, the values in
+ each position should be equal.
Testing shift()
+The next test is testShift(), which tests the functionality of the Array object's shift() method:
The shift() method removes the first item in the array and returns it (similar to pop(), which removes the item
+ from the end). In the testShift() method, shift() is called and the item is stored in value. To ensure
+ that the rest of the array is still there, Y.ArrayAssert.isNotEmpty() is called. After that, Array.areEqual() is
+ called twice, once to test the length of the array and once to test the value that was returned from shift() (which should be
+ 0). As a last test, the entire array is tested using Y.ArrayAssert.itemsAreEqual() to ensure that all of the items have shifted
+ into the appropriate positions in the array.
Testing splice()
+The next test is testSplice(), which tests the functionality of the Array object's splice() method:
The splice() method is one of the most powerful Array manipulations. It can both remove and add any number of items
+ from an array at the same time. This test begins by splicing some values into the array. When calling splice(), the first argument
+ is 1, indicating that values should be inserted at index 1 of the array; the second argument is 2, indicating that two values should be
+ removed from the array (the value in index 1 and the value in index 2); the third and fourth arguments are values that should be inserted
+ into the array at the position given by the first argument. Essentially, values 1 and 2 should end up being replaced by values 99 and 100 in
+ the array.
The first test is to determine that the length of the array is still 6 (since the previous step removed two items and then inserted two, the
+ length should still be 6). After that, Y.Assert.indexOf() is called to determine that the values of 99 and 100 are in positions
+ 1 and 2, respectively. To ensure the integrity of the entire array, Y.ArrayAssert.itemsAreEqual() is called on the array, comparing
+ it to an array with the same values. The very last step is to test the value returned from splice(), which is an array containing
+ the removed values, 1 and 2. Y.ArrayAssert.itemsAreEqual() is appropriate for this task as well.
Testing unshift()
+The next test is testUnshift(), which tests the functionality of the Array object's unshift() method:
Working similar to push(), unshift() adds a value to the array, but the item is added to the front (index 0) instead of
+ the back. This test begins by adding the value -1 to the array. The first assertion determines if the length of the array has been incremented
+ to 7 to account for the new value. After that, Y.ArrayAssert.indexOf() is used to determine if the value has been placed in the
+ correct location. The final assertions tests that the entire array is expected by using Y.ArrayAssert.itemsAreEqual().
Running the tests
+ +With all of the tests defined, the last step is to run them:
+ + + +Before running the tests, it's necessary to create a Y.Console object to display the results (otherwise the tests would run
+ but you wouldn't see the results). After that, the Y.Test.Runner is loaded with the Y.Test.Case object by calling
+ add() (any number of Y.Test.Case and TestSuite objects can be added to a Y.Test.Runner,
+ this example only adds one for simplicity). The very last step is to call run(), which begins executing the tests in its
+ queue and displays the results in the Y.Console.