Test that stagedir is mounted inside container

Author: Theofilos Manitaras

unittests/test_pipeline.py

@@ -14,6 +14,7 @@
 import reframe.utility.sanity as sn
 import unittests.utility as test_util
 
+from reframe.core.containers import _STAGEDIR_MOUNT
 from reframe.core.exceptions import (BuildError, PipelineError, ReframeError,
                                      PerformanceError, SanityError)
 
@@ -1221,11 +1222,12 @@ def __init__(self):
                 self.container_platform = platform
                 self.container_platform.image = image
                 self.container_platform.command = (
-                    "bash -c 'cd /rfm_workdir; pwd; ls; cat /etc/os-release'"
+                    f"bash -c 'cd {_STAGEDIR_MOUNT}; pwd; ls; "
+                    f"cat /etc/os-release'"
                 )
                 self.prerun_cmds = ['touch foo']
                 self.sanity_patterns = sn.all([
-                    sn.assert_found(r'^/rfm_workdir', self.stdout),
+                    sn.assert_found(rf'^{_STAGEDIR_MOUNT}', self.stdout),
                     sn.assert_found(r'^foo', self.stdout),
                     sn.assert_found(
                         r'18\.04\.\d+ LTS \(Bionic Beaver\)', self.stdout),