Comparing two arrays in unit test throwing a AssertFailedException

Question

I'm writing an unit tests for ready code and I'm receiving an unexpected AssertFailedException trying to run one of the test. Here is he:

[TestMethod]
    public void TestPositionGetter()
    {
        testPlayer.Position = new int[] { 1, 3 };
        int[] expectedPosition = testPlayer.Position;
        Assert.AreEqual(expectedPosition, testPlayer.Position);
    }

And here is the Position property in the Player class that I'm trying to test:

public int[] Position
    {
        get
        {
            return new int[] { this.PositionX, this.PositionY };
        }
        set
        {
            this.PositionX = value[0];
            this.PositionY = value[1];
        }
    }

Debugging the test, in local variables window player.Position and expectedPosition are looking similar but the test is still failing. I'm afraid the problem is coming from references.

Answer 1

You are comparing different instances of an int[]. Assert.AreEqual compares by reference. Try CollectionAssert.AreEqual.

CollectionAssert.AreEqual(expectedPosition, testPlayer.Position);

This will compare array elements.

Also, your Position property smells like bad design. Do you really have to create new array every time you get a value?