he run button in GUI again - the status bar and the test tree turn green. (Note how the GUI has reloaded the assembly automatically for you; we will keep the GUI open all the time and continue working with our code in IDE and write more tests).</p>

<p>Let's add some error checking to our Account code. We are adding the minimum balance requirement for the account to make sure that banks continue to make their money by charging your minimal overdraft protection fee. Let's add the minimum balance property to 