/* change the underlying file,
* we have to wait at least a second to see the change in the file's lastModified timestamp */
Thread.sleep(2000L);
writeLines(testFile, changedData);
similarity.refresh(null);
/* we should now see the changes in the data */
assertEquals(0.9, similarity.itemSimilarity(1L, 7L), EPSILON);
assertEquals(0.9, similarity.itemSimilarity(7L, 1L), EPSILON);
assertEquals(0.125, similarity.itemSimilarity(1L, 5L), EPSILON);