content: import os
  import shutil
  import re
  from textwrap import dedent
  
  import pytest
  
  from dash.development._r_components_generation import make_namespace_exports
  
  
  @pytest.fixture
  def make_r_dir():
      os.makedirs("R")
  
      yield
  
      shutil.rmtree("R")
  
  
  def test_r_exports(make_r_dir):
      extra_file = dedent(
          """
          # normal function syntax
          my_func <- function(a, b) {
              c <- a + b
              nested_func <- function() { stop("no!") }
              another_to_exclude = function(d) { d * d }
              another_to_exclude(c)
          }
  
          # indented (no reason but we should allow) and using = instead of <-
          # also braces in comments enclosing it {
              my_func2 = function() {
                  s <- "unmatched closing brace }"
                  ignore_please <- function() { 1 }
              }
          # }
  
          # real example from dash-table that should exclude FUN
          df_to_list <- function(df) {
            if(!(is.data.frame(df)))
              stop("!")
            setNames(lapply(split(df, seq(nrow(df))),
                            FUN = function (x) {
                              as.list(x)
                            }), NULL)
          }
  
          # single-line compressed
          util<-function(x){x+1}
  
          # prefix with . to tell us to ignore
          .secret <- function() { stop("You can't see me") }
  
          # . in the middle is OK though
          not.secret <- function() { 42 }
      """
      )
  
      components = ["Component1", "Component2"]
      prefix = "pre"
  
      expected_exports = [prefix + c for c in components] + [
          "my_func",
          "my_func2",
          "df_to_list",
          "util",
          "not.secret",
      ]
  
      mock_component_file = dedent(
          """
          nope <- function() { stop("we don't look in component files") }
      """
      )
  
      with open(os.path.join("R", "preComponent1.R"), "w") as f:
          f.write(mock_component_file)
  
      with open(os.path.join("R", "extras.R"), "w") as f:
          f.write(extra_file)
  
      exports = make_namespace_exports(components, prefix)
      print(exports)
      matches = re.findall(r"export\(([^()]+)\)", exports.replace("\n", " "))
  
      assert matches == expected_exports
  