### Question:
Calculator { public double divide(double left, double right) { addToHistory(left, '/', right); if (right == 0.0d) { throw new IllegalArgumentException( "Can't divide with zero"); } return left / right; }  static Calculator getInstance(); double add(double left, double right); double subtract(double left, double right); double multiply(double left, double right); double divide(double left, double right); List<Operation> getOperations();  }### Answer:
@Test public void testDivision() throws Exception { assertEquals(3.0d, new Calculator().divide(9.0d, 3.0d), 0.0000001d); }