Add 2 missing skip_if_not_installed("data.tree")

Author: olivroy

tests/testthat/test-create_tree.R

@@ -2,6 +2,7 @@
 
 test_that("create_trees outputs identical structure if trees have same structure", {
   skip_if_not_installed("DiagrammeR")
+  skip_if_not_installed("data.tree")
   eq <- "a <- fun(a = b)"
   arrow <- "a <- data.frame(x = qq)"
   expect_equal(
@@ -12,6 +13,7 @@ test_that("create_trees outputs identical structure if trees have same structure
 
 test_that("create_trees outputs are not identical structure if trees have different structure", {
   skip_if_not_installed("DiagrammeR")
+  skip_if_not_installed("data.tree")
   eq <- "a <- fun(a = 1:3)"
   arrow <- "a <- data.frame(x = qq)"
   expect_true(

tests/testthat/test-relocate_eq_assign.R

@@ -2,6 +2,7 @@
 # Tests code in R/relevel.R
 test_that("tree hierarchy is the same no matter whether = or <- is used", {
   skip_if_not_installed("DiagrammeR")
+  skip_if_not_installed("data.tree")
   assign_left <- create_tree(
     "x <- 5