[#190] Introduce default EC placement policy

The default policy which is similar to REP 2, but uses EC instead.

Signed-off-by: Evgenii Stratonikov <e.stratonikov@yadro.com>

src/frostfs_testlib/steps/cli/container.py

@@ -95,6 +95,7 @@ class StorageContainer:
 DEFAULT_PLACEMENT_RULE = "REP 2 IN X CBF 1 SELECT 4 FROM * AS X"
 SINGLE_PLACEMENT_RULE = "REP 1 IN X CBF 1 SELECT 4 FROM * AS X"
 REP_2_FOR_3_NODES_PLACEMENT_RULE = "REP 2 IN X CBF 1 SELECT 3 FROM * AS X"
+DEFAULT_EC_PLACEMENT_RULE = "EC 3.1"
 
 
 @reporter.step("Create Container")

src/frostfs_testlib/storage/dataclasses/policy.py

@@ -0,0 +1,13 @@
+from dataclasses import dataclass
+
+
+@dataclass
+class PlacementPolicy:
+    name: str
+    value: str
+
+    def __str__(self) -> str:
+        return self.name
+
+    def __repr__(self) -> str:
+        return self.__str__()