add unit tests, simplify code; closes tidyverse#3314

Author: clauswilke

R/annotation.r

@@ -48,8 +48,8 @@ annotate <- function(geom, x = NULL, y = NULL, xmin = NULL, xmax = NULL,
   lengths <- vapply(aesthetics, length, integer(1))
   n <- unique(setdiff(lengths, 1L))
   if (length(n) == 0L) n <- 1L # if all lengths are equal to 1L then above line fails, this fixes that
-  unequal <- length(n) > 1L
-  if (unequal) {
+
+  if (length(n) > 1L) {
     bad <- lengths != 1L
     details <- paste(names(aesthetics)[bad], " (", lengths[bad], ")",
       sep = "", collapse = ", ")

tests/testthat/test-performance.R

@@ -1,5 +1,8 @@
 context("Performance related alternatives")
 
+# ********************
+# modify_list()
+
 testlist <- list(
   a = 5.5,
   b = "x",
@@ -32,3 +35,35 @@ test_that("modify_list erases null elements", {
   expect_null(res$c)
   expect_named(res, c('a', 'b', 'd'))
 })
+
+
+# ********************
+# new_data_frame()
+
+test_that("new_data_frame handles zero-length inputs", {
+  # zero-length input creates zero-length data frame
+  d <- new_data_frame(list(x = numeric(0), y = numeric(0)))
+  expect_equal(nrow(d), 0L)
+
+  # constants are ignored in the context of zero-length input
+  d <- new_data_frame(list(x = numeric(0), y = numeric(0), z = 1))
+  expect_equal(nrow(d), 0L)
+
+  # vectors of length > 1 don't mix with zero-length input
+  expect_error(
+    new_data_frame(list(x = numeric(0), y = numeric(0), z = 1, a = c(1, 2))),
+    "Elements must equal the number of rows or 1"
+  )
+
+  # explicit recycling doesn't work with zero-length input
+  expect_error(
+    new_data_frame(list(x = numeric(0), z = 1), n = 5),
+    "Elements must equal the number of rows or 1"
+  )
+  # but it works without
+  d <- new_data_frame(list(x = 1, y = "a"), n = 5)
+  expect_equal(nrow(d), 5L)
+  expect_identical(d$x, rep(1, 5L))
+  expect_identical(d$y, rep("a", 5L))
+
+})