add test

Author: teunbrand

tests/testthat/test-stat-chain.R

@@ -0,0 +1,31 @@
+test_that("stat_chain can chain multiple stats", {
+
+  df <- data.frame(x = c(1, 1.9, 2.1, 3, 3, 3))
+
+  p <- ggplot(df, aes(x)) +
+    stat_chain(
+      stats = "bin", stat.params = list(list(breaks = c(0.5:3.5)))
+    ) +
+    stat_chain(
+      stats = c("unique", "bin"),
+      stat.params = list(NULL, list(breaks = 0.5:3.5))
+    ) +
+    stat_chain(
+      stats = c("unique", "bin"),
+      stat.params = list(NULL, list(breaks = 0.5:3.5)),
+      redirect = list(NULL, aes(y = -count))
+    )
+  p <- ggplot_build(p)
+
+  ld <- get_layer_data(p, 1L)
+  expect_equal(ld$x, 1:3)
+  expect_equal(ld$y, 1:3)
+
+  ld <- get_layer_data(p, 2L)
+  expect_equal(ld$x, 1:3)
+  expect_equal(ld$y, c(1, 2, 1))
+
+  ld <- get_layer_data(p, 3L)
+  expect_equal(ld$x, 1:3)
+  expect_equal(ld$y, c(-1, -2, -1))
+})