Add repr and str for most classes used in parametrize

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

tests/test_dataclasses.py

@@ -0,0 +1,37 @@
+from typing import Any
+
+import pytest
+
+from frostfs_testlib.s3 import AwsCliClient, Boto3ClientWrapper
+from frostfs_testlib.storage.dataclasses.frostfs_services import (
+    HTTPGate,
+    InnerRing,
+    MorphChain,
+    S3Gate,
+    StorageNode,
+)
+from frostfs_testlib.storage.dataclasses.object_size import ObjectSize
+
+
+class TestDataclassesStr:
+    """Here we are testing important classes string representation."""
+
+    @pytest.mark.parametrize(
+        "obj, expected",
+        [
+            (Boto3ClientWrapper, "Boto3 client"),
+            (AwsCliClient, "AWS CLI"),
+            (ObjectSize("simple", 1), "simple object size"),
+            (ObjectSize("simple", 10), "simple object size"),
+            (ObjectSize("complex", 5000), "complex object size"),
+            (ObjectSize("complex", 5555), "complex object size"),
+            (StorageNode, "StorageNode"),
+            (MorphChain, "MorphChain"),
+            (S3Gate, "S3Gate"),
+            (HTTPGate, "HTTPGate"),
+            (InnerRing, "InnerRing"),
+        ],
+    )
+    def test_classes_string_representation(self, obj: Any, expected: str):
+        assert f"{obj}" == expected
+        assert repr(obj) == expected