Move shared code to testlib

Signed-off-by: Andrey Berezin <a.berezin@yadro.com>

src/frostfs_testlib/testing/cluster_test_base.py

@@ -0,0 +1,32 @@
+from typing import Optional
+
+from frostfs_testlib.reporter import get_reporter
+from frostfs_testlib.shell import Shell
+from frostfs_testlib.steps import epoch
+from frostfs_testlib.storage.cluster import Cluster
+from frostfs_testlib.storage.dataclasses.frostfs_services import StorageNode
+
+reporter = get_reporter()
+
+
+# To skip adding every mandatory singleton dependency to EACH test function
+class ClusterTestBase:
+    shell: Shell
+    cluster: Cluster
+
+    @reporter.step_deco("Tick {epochs_to_tick} epochs")
+    def tick_epochs(self, epochs_to_tick: int, alive_node: Optional[StorageNode] = None):
+        for _ in range(epochs_to_tick):
+            self.tick_epoch(alive_node)
+
+    def tick_epoch(self, alive_node: Optional[StorageNode] = None):
+        epoch.tick_epoch(self.shell, self.cluster, alive_node=alive_node)
+
+    def wait_for_epochs_align(self):
+        epoch.wait_for_epochs_align(self.shell, self.cluster)
+
+    def get_epoch(self):
+        return epoch.get_epoch(self.shell, self.cluster)
+
+    def ensure_fresh_epoch(self):
+        return epoch.ensure_fresh_epoch(self.shell, self.cluster)