+
+ // More date span arithmetics tests
+ wxDateTime dtd1(5, wxDateTime::Jun, 1998);
+ wxDateTime dtd2(6, wxDateTime::Aug, 1999);
+
+ // All parts in dtd2 is after dtd1
+ CPPUNIT_ASSERT_EQUAL( wxDateSpan(1, 2, 0, 1), dtd2.DiffAsDateSpan(dtd1) );
+
+ // Year and month after, day earlier, so no full month
+ // Jul has 31 days, so it's 31 - 5 + 4 = 30, or 4w 2d
+ dtd2.Set(4, wxDateTime::Aug, 1999);
+ CPPUNIT_ASSERT_EQUAL( wxDateSpan(1, 1, 4, 2), dtd2.DiffAsDateSpan(dtd1) );
+
+ // Year and day after, month earlier, so no full year, but same day diff as
+ // first example
+ dtd2.Set(6, wxDateTime::May, 1999);
+ CPPUNIT_ASSERT_EQUAL( wxDateSpan(0, 11, 0, 1), dtd2.DiffAsDateSpan(dtd1) );
+
+ // Year after, month and day earlier, so no full month and no full year
+ // April has 30 days, so it's 30 - 5 + 4 = 29, or 4w 1d
+ dtd2.Set(4, wxDateTime::May, 1999);
+ CPPUNIT_ASSERT_EQUAL( wxDateSpan(0, 10, 4, 1), dtd2.DiffAsDateSpan(dtd1) );
+
+ // And a reverse. Now we should use days in Jun (again 30 => 4w 1d)
+ CPPUNIT_ASSERT_EQUAL( wxDateSpan(0, -10, -4, -1), dtd1.DiffAsDateSpan(dtd2) );