mock the which as it is used (#5986)

conans/test/unittests/client/tools/system_pm_test.py

@@ -1,27 +1,18 @@
-import os
-import stat
-
 import mock
 import platform
 import six
 import unittest
-
-from conans.client.tools import environment_append
-
-from conans.test.utils.test_files import temp_folder
 from six import StringIO
 
 from conans import tools
 from conans.client.output import ConanOutput
 from conans.client.tools.files import which
 from conans.client.tools.oss import OSInfo
-from conans.client.tools.system_pm import ChocolateyTool, SystemPackageTool,\
-    AptTool
+from conans.client.tools.system_pm import ChocolateyTool, SystemPackageTool, AptTool
 from conans.errors import ConanException
 from conans.test.unittests.util.tools_test import RunnerMock
-from conans.test.utils.tools import TestBufferConanOutput
 from conans.test.utils.conanfile import MockSettings, MockConanfile
-from conans.util.files import save
+from conans.test.utils.tools import TestBufferConanOutput
 
 
 class SystemPackageToolTest(unittest.TestCase):
@@ -157,12 +148,7 @@ def system_package_tool_test(self):
             spt.update()
             self.assertEqual(runner.command_called, "sudo -A apt-get update")
 
-            # Fake a dnf exe and check if for fedora it used it
-            tmp = temp_folder()
-            dnf_path = os.path.join(tmp, "dnf{}".format(".exe" if platform.system() == "Windows" else ".sh"))
-            save(dnf_path, "fake_executable")
-            os.chmod(dnf_path, stat.S_IEXEC)
-            with environment_append({"PATH": tmp}):
+            with mock.patch("conans.client.tools.oss.which", return_value=True):
                 os_info.linux_distro = "fedora"
                 spt = SystemPackageTool(runner=runner, os_info=os_info, output=self.out)
                 spt.update()