MinusOperator.java

@Test
public void addNumbersWhenMinusOperatorIsFound() {
    ReversePolishNotation rpn = new ReversePolishNotation();
    double result = rpn.evaluate("5 5 2 + -");
    assertEquals(2.0, result, 0.1);
}

@Test
public void addNumbersWhenMultiplyOperatorIsFound() {
    ReversePolishNotation rpn = new ReversePolishNotation();
    double result = rpn.evaluate("5 5 2 + *");
    assertEquals(35.0, result, 0.1);
}