Fix tests in test_git with hard coded env setter

Commands for setting environment variables are platform specific. Tests are failing on Windows, as
they have harded coded commands for setting environment variables. This commit changes to use the
`get_envrionment_variable_setter_command` method in process_utils module to make the tests
cross-platform.

test/unit/project_type/test_git.py

@@ -8,7 +8,7 @@
 
 from app.project_type.git import Git
 from app.util.conf.configuration import Configuration
-from app.util.process_utils import is_windows
+from app.util.process_utils import is_windows, get_environment_variable_setter_command
 from test.framework.base_unit_test_case import BaseUnitTestCase
 from test.framework.comparators import AnyStringMatching
 
@@ -46,12 +46,15 @@ def test_execute_command_in_project_specifies_cwd_if_exists(self):
         self.os_path_exists_mock.return_value = True
         project_type_popen_patch = self._patch_popen()
 
+        fake_project_directory = 'proj_dir'
+        fake_command = 'some_command'
         git_env = Git("ssh://scm.dev.box.net/box/www/current", 'origin', 'refs/changes/78/151978/27')
-        git_env.project_directory = 'proj_dir'
-        git_env.execute_command_in_project('some_command')
+        git_env.project_directory = fake_project_directory
+        git_env.execute_command_in_project(fake_command)
+        env_setter = get_environment_variable_setter_command('PROJECT_DIR', fake_project_directory)
         project_type_popen_patch.assert_called_once_with(
-            'export PROJECT_DIR="proj_dir"; some_command',
-            cwd='proj_dir',
+            '{} {}'.format(env_setter, fake_command),
+            cwd=fake_project_directory,
             shell=ANY,
             stdout=ANY,
             stderr=ANY,
@@ -61,11 +64,14 @@ def test_execute_command_in_project_specifies_cwd_if_exists(self):
     def test_execute_command_in_project_type_specifies_cwd_if_doesnt_exist(self):
         project_type_popen_patch = self._patch_popen()
 
+        fake_project_directory = 'proj_dir'
+        fake_command = 'some_command'
         git_env = Git("ssh://scm.dev.box.net/box/www/current", 'origin', 'refs/changes/78/151978/27')
-        git_env.project_directory = 'proj_dir'
-        git_env.execute_command_in_project('some_command')
+        git_env.project_directory = fake_project_directory
+        git_env.execute_command_in_project(fake_command)
+        env_setter = get_environment_variable_setter_command('PROJECT_DIR', fake_project_directory)
         project_type_popen_patch.assert_called_once_with(
-            'export PROJECT_DIR="proj_dir"; some_command',
+            '{} {}'.format(env_setter, fake_command),
             cwd=None,
             shell=ANY,
             stdout=ANY,