Add tests for the shape argument in geom_curve()

Author: fmarotta

tests/testthat/test-geom-curve.R

@@ -9,3 +9,27 @@ test_that("geom_curve flipping works", {
   expect_doppelganger("flipped geom_curve", p + scale_y_reverse())
 
 })
+
+test_that("geom_curve shape works", {
+
+  df <- data.frame(x = c(1, 3), xend = c(2, 4), y = c(0, 1), yend = c(2, 1.5))
+
+  p_0 <- ggplot(df, aes(x, y, xend = xend, yend = yend)) +
+    geom_curve(arrow = arrow(), shape = 0, ncp = 1, curvature = 1)
+
+  # This will use `square = FALSE` in curveGrob because angle != 90
+  p_0_not_square <- ggplot(df, aes(x, y, xend = xend, yend = yend)) +
+    geom_curve(arrow = arrow(), shape = 0, ncp = 1, curvature = 1, angle = 60)
+
+  p_1 <- ggplot(df, aes(x, y, xend = xend, yend = yend)) +
+    geom_curve(arrow = arrow(), shape = 1)
+
+  p_m1 <- ggplot(df, aes(x, y, xend = xend, yend = yend)) +
+    geom_curve(arrow = arrow(), shape = -1, angle = 40)
+
+  expect_doppelganger("shape=0 geom_curve", p_0)
+  expect_doppelganger("shape=0 geom_curve", p_0_not_square)
+  expect_doppelganger("shape=1 geom_curve", p_1)
+  expect_doppelganger("shape=-1 geom_curve", p_m1)
+
+})