Assertion { public static void positive(long number, String name) { if (number <= 0) { throw new InvalidArgumentException(name + " should be positive"); } }  static void notNull(T argument, String format, Object... args); static void notNullOrEmpty(String argument, String name); static void negative(long number, String name); static void positive(long number, String name); static void nonNegative(long number, String name); static void nonPositive(long number, String name);  }
@Test(expected = InvalidArgumentException.class) public void positive_withNegative() throws Exception { Assertion.positive(-1, "number"); }
@Test public void positive_ok() throws Exception { Assertion.positive(1, "number"); }
@Test(expected = InvalidArgumentException.class) public void positive_withZero() throws Exception { Assertion.positive(0, "number"); }