It is sometimes useful to check if a generated PDF document has exactly one page. Or maybe you want to ensure that a document has less than 6 pages, because otherwise you have to pay higher postage. PDFUnit provides suitable test methods:

// Method for tests with pages:
.hasNumberOfPages(..) 
.hasLessPagesThan(..) 
.hasMorePagesThan(..)

You can check the number of pages like this:

@Test
public void hasNumberOfPages() throws Exception {
  String filename = "documentUnderTest.pdf";
  
  AssertThat.document(filename)
            .hasNumberOfPages(1)
  ;
}

Tests are also possible with a minimum or maximum number of pages.

@Test
public void hasLessPagesThan() throws Exception {
  String filename = "documentUnderTest.pdf";
  int upperLimitExclusive = 6; // The document has 5 pages
  
  AssertThat.document(filename)
            .hasLessPagesThan(upperLimitExclusive)  
  ;
}

@Test
public void hasMorePagesThan() throws Exception {
  String filename = "documentUnderTest.pdf";
  int lowerLimitExclusive = 2; // The document has 5 pages
  
  AssertThat.document(filename)
            .hasMorePagesThan(lowerLimitExclusive)  
  ;
}

Of course methods can be concatenated:

@Test
public void hasNumberOfPages_InRange() throws Exception {
  String filename = "documentUnderTest.pdf";
  // The current document has 5 pages
  int lowerLimit_2 = 2;  // the limit is exclusive
  int upperLimit_8 = 8;  // the limit is exclusive
  
  AssertThat.document(filename)
            .hasMorePagesThan(lowerLimit_2)
            .hasLessPagesThan(upperLimit_8)
  ;
}

Don't omit tests with page numbers just because you might think they are too simple. Experience shows that you can find errors in the context of a primitive test that you would not have found without the test.