update test: Limit base versions

This change will limit the active base versions to the first one and
the last four available versions for each the previous and the current
branch (so it limits the test to up to 10 versions in total).

Change-Id: Iacfdb424482e6f113d35f4719f94355238e13717
(cherry picked from commit 2d85ba5)

tests/update/conftest.py

@@ -26,8 +26,9 @@
 from cmk.utils.paths import omd_root
 
 LOGGER = logging.getLogger(__name__)
-DUMPS_DIR = Path(__file__).parent.resolve() / "dumps"
-RULES_DIR = repo_path() / "tests" / "update" / "rules"
+MODULE_PATH = Path(__file__).parent.resolve()
+DUMPS_DIR = MODULE_PATH / "dumps"
+RULES_DIR = MODULE_PATH / "rules"
 
 
 def pytest_addoption(parser):
@@ -71,28 +72,58 @@ def pytest_configure(config):
 
 @dataclasses.dataclass
 class BaseVersions:
-    """Get all base versions used for the test."""
+    """Get all base versions used for the test. Up to five versions are used per branch:
+    The first one and the last four.
+    """
 
-    with open(Path(__file__).parent.resolve() / "base_versions.json") as f:
-        BASE_VERSIONS_STR = json.load(f)
+    @staticmethod
+    def _limit_versions(versions: list[str], min_version: CMKVersion) -> list[str]:
+        """Select supported earliest and latest versions and eliminate duplicates"""
+        max_earliest_versions = 1
+        max_latest_versions = 4
+
+        active_versions = [_ for _ in versions if CMKVersion(_, min_version.edition) >= min_version]
+        earliest_versions = active_versions[0:max_earliest_versions]
+        latest_versions = active_versions[-max_latest_versions:]
+        # do not use a set to retain the order
+        return list(dict.fromkeys(earliest_versions + latest_versions))
+
+    MIN_VERSION = get_min_version()
 
     if version_from_env().is_saas_edition():
-        BASE_VERSIONS = [
-            CMKVersion(CMKVersion.DAILY, edition_from_env(Edition.CSE), "2.3.0", "2.3.0")
-        ]
+        BASE_VERSIONS = [CMKVersion(CMKVersion.DAILY, Edition.CSE, "2.3.0", "2.3.0")]
     else:
+        base_versions_pb_file = MODULE_PATH / "base_versions_previous_branch.json"
+        if not base_versions_pb_file.exists():
+            base_versions_pb_file = MODULE_PATH / "base_versions.json"
+        BASE_VERSIONS_PB = _limit_versions(
+            json.loads(base_versions_pb_file.read_text(encoding="utf-8")), MIN_VERSION
+        )
+
+        base_versions_cb_file = MODULE_PATH / "base_versions_current_branch.json"
+        BASE_VERSIONS_CB = (
+            _limit_versions(
+                json.loads(base_versions_cb_file.read_text(encoding="utf-8")),
+                MIN_VERSION,
+            )
+            if base_versions_cb_file.exists()
+            else []
+        )
+
         BASE_VERSIONS = [
-            CMKVersion(base_version_str, edition_from_env(Edition.CEE))
-            for base_version_str in BASE_VERSIONS_STR
-            if not version_from_env().is_saas_edition()
+            CMKVersion(
+                base_version_str,
+                edition_from_env(Edition.CEE),
+            )
+            for base_version_str in BASE_VERSIONS_PB + BASE_VERSIONS_CB
         ]
 
 
 @dataclasses.dataclass
 class InteractiveModeDistros:
     @staticmethod
     def get_supported_distros():
-        with open(Path(__file__).parent.resolve() / "../../editions.yml") as stream:
+        with open(repo_path() / "editions.yml") as stream:
             yaml_file = yaml.safe_load(stream)
 
         return yaml_file["daily_extended"]