Tests: Allow extra run conditions for NM tests

To be able to restrict running tests with NM, for example only on
CentOS/RHEL 7, allow to specify an extra run condition for the generated
shims.

tests/ensure_provider_tests.py

@@ -29,6 +29,8 @@ MINIMUM_NM_VERSION_CHECK = """
     - NetworkManager_version.stdout is version({minimum_nm_version}, '>=')
 """
 
+EXTRA_RUN_CONDITION_PREFIX = "    - "
+
 RUN_PLAYBOOK_WITH_NM = """# SPDX-License-Identifier: BSD-3-Clause
 # This file was generated by ensure_provider_tests.py
 ---
@@ -50,9 +52,10 @@ RUN_PLAYBOOK_WITH_NM = """# SPDX-License-Identifier: BSD-3-Clause
 - import_playbook: {test_playbook}
   when:
     - ansible_distribution_major_version != '6'
-{minimum_nm_version_check}"""
+{minimum_nm_version_check}{extra_run_condition}"""
 
 MINIMUM_VERSION = "minimum_version"
+EXTRA_RUN_CONDITION = "extra_run_condition"
 NM_ONLY_TESTS = {
     "playbooks/tests_ethtool_features.yml": {
         MINIMUM_VERSION: "'1.20.0'",
@@ -88,6 +91,14 @@ def create_nm_playbook(test_playbook):
     nm_testfile = fileroot + "_nm.yml"
 
     minimum_nm_version = NM_ONLY_TESTS.get(test_playbook, {}).get(MINIMUM_VERSION)
+    extra_run_condition = NM_ONLY_TESTS.get(test_playbook, {}).get(
+        EXTRA_RUN_CONDITION, ""
+    )
+    if extra_run_condition:
+        extra_run_condition = "{}{}\n".format(
+            EXTRA_RUN_CONDITION_PREFIX, extra_run_condition
+        )
+
     nm_version_check = ""
     if minimum_nm_version:
         nm_version_check = MINIMUM_NM_VERSION_CHECK.format(
@@ -98,6 +109,7 @@ def create_nm_playbook(test_playbook):
         test_playbook=test_playbook,
         get_nm_version=minimum_nm_version and GET_NM_VERSION or "",
         minimum_nm_version_check=nm_version_check,
+        extra_run_condition=extra_run_condition,
     )
 
     return nm_testfile, nominal_nm_testfile_data