From fd505e08712cf416e7bbc1cd849e4ae1e42c0683 Mon Sep 17 00:00:00 2001
From: hadley <h.wickham@gmail.com>
Date: Mon, 16 May 2016 15:39:07 -0500
Subject: [PATCH] Preserve ordered attribute in expand.

Fixes #165
---
 NEWS.md                      | 3 +++
 R/spread.R                   | 2 +-
 tests/testthat/test-expand.R | 6 ++++++
 3 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/NEWS.md b/NEWS.md
index 93fcc8e65..fadb67121 100644
--- a/NEWS.md
+++ b/NEWS.md
@@ -1,5 +1,8 @@
 # tidyr 0.4.1.9000
 
+* `expand()` (and hence `complete()`) preserves the ordered attribute of 
+  factors (#165).
+
 * `complete()` preserves grouping created by dplyr (#168).
 
 * `nest()` now returns correct output if every variable is nested (#186).
diff --git a/R/spread.R b/R/spread.R
index ba6f84d5e..e14090bc2 100644
--- a/R/spread.R
+++ b/R/spread.R
@@ -160,7 +160,7 @@ ulevels <- function(x) {
   if (is.factor(x)) {
     x <- addNA(x, ifany = TRUE)
     levs <- levels(x)
-    factor(levs, levels = levs)
+    factor(levs, levels = levs, ordered = is.ordered(x))
   } else {
     sort(unique(x))
   }
diff --git a/tests/testthat/test-expand.R b/tests/testthat/test-expand.R
index d3377c1ba..50ac92716 100644
--- a/tests/testthat/test-expand.R
+++ b/tests/testthat/test-expand.R
@@ -53,3 +53,9 @@ test_that("expand respects groups", {
   expect_equal(out$data[[2]], dplyr::data_frame(b = 1L, c = 1L))
 })
 
+test_that("preserves ordered factors", {
+  df <- dplyr::data_frame(a = ordered("a"))
+  out <- expand(df, a)
+
+  expect_equal(df$a, ordered("a"))
+})