test_that("Test rowdiff",
          code = {
            skip_on_oldrel()
            
            dummy_data <- data.frame(A = c(1, 1, 2, 3), B = c(4, 5, 3, 7))
            
            the_test <- rowdiff(dummy_data,
                                direction = "reverse")[3, 2]
            expect_equal(the_test,-2)
            
            another_test <- rowdiff(dummy_data, direction = "forward")[3, 2]
            expect_equal(another_test,-4)
            
            # Replace NAs frrom calculation
            expect_equal(rowdiff(
              dummy_data,
              na.rm = TRUE,
              na_action = "value",
              value = 0
            )[4, 1],
            0)
            
            expect_error(rowdiff(yields, direction = "gibberish"))
            
            expect_equal(ncol(rowdiff(yields, exclude = "factor")), 3)
          })