How to test exception in Java Junit
<p>I created the following method that I use to validate Roman numbers converter.
In JUnit the test passes but the program doesn't throw any exception.
Where did I wrong?</p>

<pre><code>public void validateState(String number){
    if(!number.matches("^M{0,4}(CM|CD|D?C{0,3})(XC|XL|L?X{0,3})(IX|IV|V?I{0,3})$"))
        throw new IllegalArgumentException("Invalid number");

    System.out.println("Invalid number");
}
</code></pre>

<p>Test:</p>

<pre><code>@Test(expected = IllegalArgumentException.class)
public void test15() throws Exception {
    new RomanNumber("").validateState("MMMMM");
}
</code></pre>

<p>Thank you for the help.</p>