code: def test_ensure_env_decorator_sets_gdal_data_prefix(
      find_file, gdalenv, monkeypatch, tmpdir
  ):
      """fiona.env.ensure_env finds GDAL data under a prefix"""
  
      @ensure_env
      def f():
          return getenv()["GDAL_DATA"]
  
      find_file.return_value = None
      tmpdir.ensure("share/gdal/header.dxf")
      monkeypatch.delenv("GDAL_DATA", raising=False)
      monkeypatch.setattr(_env, "__file__", str(tmpdir.join("fake.py")))
      monkeypatch.setattr(sys, "prefix", str(tmpdir))
  
      assert f() == str(tmpdir.join("share").join("gdal"))
  
file_path: Fiona/tests/test_env.py
imports: import os
  import sys
  from unittest import mock
  import boto3
  import pytest
  import fiona
  from fiona import _env
  from fiona.env import getenv, hasenv, ensure_env, ensure_env_with_credentials
  from fiona.errors import FionaDeprecationWarning
  from fiona.session import AWSSession, GSSession
label_desc: Use image node_id 4 for calling a global function with example usage: test_ensure_env_decorator_sets_gdal_data_prefix(find_file, gdalenv, monkeypatch, tmpdir) and returns: getenv