Unit test for coverting comma separated string of ints to int array

I'm new to this, so really don't know if i'm doing this right. The code I want to test is:

public int[] IntArray(string text)
    {
        return text.Split(',').Select(x => int.Parse(x.Trim())).ToArray();
    }

The test I already have is not complete, so hoping someone can help:

 [TestClass]
  public class ContextHelperTests
 {
     public ContextHelper CreateTarget()
     {
       var context = new ContextHelper()            
     };

       return new ContextHelper();
  }

   [TestMethod]
   public void TestContextHelper()
      {
        // Arrange
      var expectedResult = 12,3;
      }

        // Act
      var values = context.Split(',');
      int actualResult = values.Select(x => int.Parse(x)).ToArray();

      // Assert
      Assert.That(actualResult, Is.EqualTo(expectedResult));