### Question:
MorePreconditions { public static String checkNotBlank(String argument) { return checkNotBlank(argument, ARG_NOT_BLANK_MSG); } private  MorePreconditions(); static String checkNotBlank(String argument); static String checkNotBlank(String argument, String message, Object... args); static T checkNotBlank(T argument); static T checkNotBlank(T argument, String message,
      Object... args);  }### Answer:
@Test(expected = NullPointerException.class) public void testCheckNotBlankStringNull() { MorePreconditions.checkNotBlank((String) null); }
@Test(expected = IllegalArgumentException.class) public void testCheckNotBlankStringEmpty() { MorePreconditions.checkNotBlank(""); }
@Test(expected = IllegalArgumentException.class) public void testCheckNotBlankSpaces() { MorePreconditions.checkNotBlank(" "); }
@Test(expected = IllegalArgumentException.class) public void testCheckNotBlankWhitespace() { MorePreconditions.checkNotBlank("\t\r\n "); }
@Test public void testCheckNotBlankStringValid() { String argument = new String("foo"); assertSame(argument, MorePreconditions.checkNotBlank(argument)); }
@Test public void testCheckNotBlankStringExceptionFormatting() { try { MorePreconditions.checkNotBlank((String) null, "the meaning of life is %s", 42); } catch (NullPointerException e) { assertEquals("the meaning of life is 42", e.getMessage()); } try { MorePreconditions.checkNotBlank("", "wing beats per second is %s", 43); } catch (IllegalArgumentException e) { assertEquals("wing beats per second is 43", e.getMessage()); } }
@Test(expected = NullPointerException.class) public void testCheckNotBlankIterableNull() { MorePreconditions.checkNotBlank((Iterable<?>) null); }
@Test(expected = IllegalArgumentException.class) public void testCheckNotBlankIterableEmpty() { MorePreconditions.checkNotBlank(ImmutableList.<Object>of()); }
@Test public void testCheckNotBlankIterableValid() { ImmutableList<String> argument = ImmutableList.of(""); ImmutableList<String> result = MorePreconditions.checkNotBlank(argument); assertSame(argument, result); }
@Test public void testCheckNotBlankIterableExceptionFormatting() { try { MorePreconditions.checkNotBlank((Iterable<?>) null, "the meaning of life is %s", 42); } catch (NullPointerException e) { assertEquals("the meaning of life is 42", e.getMessage()); } try { MorePreconditions.checkNotBlank(ImmutableList.of(), "wing beats per second is %s", 43); } catch (IllegalArgumentException e) { assertEquals("wing beats per second is 43", e.getMessage()); } }