diff --git a/tests/testthat/test-position-nudgestack.R b/tests/testthat/test-position-nudgestack.R
index cda3fd3e20..6ac2277a09 100644
--- a/tests/testthat/test-position-nudgestack.R
+++ b/tests/testthat/test-position-nudgestack.R
@@ -25,3 +25,96 @@ test_that("position_nudgestack draws correctly", {
     stock_marked
   )
 })
+
+
+test_that("nudging works in both dimensions simultaneously", {
+  # individual nudge value for continuous data
+  set.seed(111)
+
+  df <- data_frame(x = 1:3)
+
+  p <- ggplot(df, aes(x, x, xmax = x, xmin = x, ymax = x, ymin = x)) +
+    geom_col(position = position_nudgestack(x = 0.5, y = 2))
+
+  data <- layer_data(p)
+
+  expect_equal(data$x, 1.5:3.5)
+  expect_equal(data$xmin, 1.05:3.05)
+  expect_equal(data$xmax, 1.95:3.95)
+  expect_equal(data$y, 3:5)
+  expect_equal(data$ymin, c(2,2,2))
+  expect_equal(data$ymax, 3:5)
+
+})
+
+test_that("nudging works for discrete values correctly", {
+  set.seed(111)
+
+  # x nudge value for discrete data
+  series <- data.frame(
+    time = factor(c(rep(1, 4),rep(2, 4), rep(3, 4), rep(4, 4))),
+    type = rep(c('a', 'b', 'c', 'd'), 4),
+    value = rpois(16, 10)
+  )
+
+  p <- ggplot(series, aes(time, value, group = type)) +
+    geom_line(aes(colour = type), position = position_nudgestack(x = 0.5)) +
+    geom_point(aes(colour = type), position = position_nudgestack(x = 0.5))
+
+  data <- layer_data(p)
+
+  expect_equal(data$x, c(rep(1.5, 4),rep(2.5, 4), rep(3.5, 4), rep(4.5, 4)))
+  expect_equal(data$xmin, c(rep(1.5, 4),rep(2.5, 4), rep(3.5, 4), rep(4.5, 4)))
+  expect_equal(data$xmax, c(rep(1.5, 4),rep(2.5, 4), rep(3.5, 4), rep(4.5, 4)))
+
+})
+
+
+test_that("data is sorted prior to stacking", {
+  df <- data_frame(
+    x = rep(c(1:10), 3),
+    var = rep(c("a", "b", "c"), 10),
+    y = round(runif(30, 1, 5))
+  )
+  p <- ggplot(df, aes(x = x, y = y, fill = var)) +
+    geom_col(position = position_nudgestack(x = 0.5))
+
+  dat <- layer_data(p)
+  expect_true(all(dat$group == 3:1))
+})
+
+test_that("negative and positive values are handled separately", {
+  df <- data_frame(
+    x = c(1,1,1,2,2),
+    g = c(1,2,3,1,2),
+    y = c(1,-1,1,2,-3)
+  )
+  p <- ggplot(df, aes(x, y, fill = factor(g))) +
+    geom_col(position = position_nudgestack(x = 0.5))
+  dat <- layer_data(p)
+
+  expect_equal(dat$ymin[dat$x == 1.5], c(0, -1, 1))
+  expect_equal(dat$ymax[dat$x == 1.5], c(1, 0, 2))
+
+  expect_equal(dat$ymin[dat$x == 2.5], c(0, -3))
+  expect_equal(dat$ymax[dat$x == 2.5], c(2, 0))
+})
+
+test_that("can request reverse stacking", {
+  df <- data_frame(
+    y = c(-2, 2, -1, 1),
+    g = c("a", "a", "b", "b")
+  )
+  p <- ggplot(df, aes(1, y, fill = g)) +
+    geom_col(position = position_nudgestack(x = 0.5, reverse = TRUE))
+  dat <- layer_data(p)
+  expect_equal(dat$ymin, c(-2, 0, -3, 2))
+})
+
+test_that("position_nudgestack() can stack correctly when ymax is NA", {
+  df <- data_frame(x = c(1, 1), y = c(1, 1))
+  p <- ggplot(df, aes(x, y, ymax = NA_real_)) +
+    geom_point(position = position_nudgestack(x = 0.5))
+  expect_equal(layer_data(p)$y, c(1, 2))
+})
+