Address PR comments

Author: Theofilos Manitaras

docs/config_reference.rst

@@ -467,6 +467,7 @@ ReFrame can launch containerized applications, but you need to configure properl
    The type of the container platform.
    Available values are the following:
 
+   - ``Apptainer``: The `Apptainer <https://apptainer.org/>`__ container runtime.
    - ``Docker``: The `Docker <https://www.docker.com/>`__ container runtime.
    - ``Sarus``: The `Sarus <https://sarus.readthedocs.io/>`__ container runtime.
    - ``Shifter``: The `Shifter <https://github.com/NERSC/shifter>`__ container runtime.

reframe/core/containers.py

@@ -268,7 +268,11 @@ def launch_command(self, stagedir):
 
 class Apptainer(Singularity):
     '''Container platform backend for running containers with `Apptainer
-    <https://apptainer.org/>`__.'''
+    <https://apptainer.org/>`__.
+
+    .. versionadded:: 4.0.0
+
+    '''
 
     def __init__(self):
         super().__init__()

unittests/test_containers.py

@@ -102,7 +102,7 @@ def expected_cmd_mount_points(container_variant):
                 '--mount=type=bind,source="/path/two",destination="/two" '
                 '--mount=type=bind,source="/foo",destination="/rfm_workdir" '
                 'load/library/image:tag cmd')
-    elif container_variant in {'Singularity'}:
+    elif container_variant == 'Singularity':
         return ('singularity exec -B"/path/one:/one" '
                 '-B"/path/two:/two" -B"/foo:/rfm_workdir" '
                 '--pwd /rfm_workdir image:tag cmd')
@@ -114,7 +114,7 @@ def expected_cmd_mount_points(container_variant):
         return ('singularity run -B"/path/one:/one" '
                 '-B"/path/two:/two" -B"/foo:/rfm_workdir" '
                 '--pwd /rfm_workdir image:tag')
-    elif container_variant in {'Apptainer'}:
+    elif container_variant == 'Apptainer':
         return ('apptainer exec -B"/path/one:/one" '
                 '-B"/path/two:/two" -B"/foo:/rfm_workdir" '
                 '--pwd /rfm_workdir image:tag cmd')
@@ -194,7 +194,7 @@ def expected_cmd_run_opts(container_variant):
                 '--mount=type=bind,source="/path/one",destination="/one" '
                 '--mount=type=bind,source="/foo",destination="/rfm_workdir" '
                 '--mpi --foo --bar image:tag cmd')
-    elif container_variant in {'Singularity'}:
+    elif container_variant == 'Singularity':
         return ('singularity exec -B"/path/one:/one" -B"/foo:/rfm_workdir" '
                 '--foo --bar image:tag cmd')
     elif container_variant == 'Singularity+cuda':
@@ -203,7 +203,7 @@ def expected_cmd_run_opts(container_variant):
     elif container_variant == 'Singularity+nocommand':
         return ('singularity run -B"/path/one:/one" -B"/foo:/rfm_workdir" '
                 '--foo --bar image:tag')
-    elif container_variant in {'Apptainer'}:
+    elif container_variant == 'Apptainer':
         return ('apptainer exec -B"/path/one:/one" -B"/foo:/rfm_workdir" '
                 '--foo --bar image:tag cmd')
     elif container_variant == 'Apptainer+cuda':