Fix string representation for load params with empty fields

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

src/frostfs_testlib/load/load_config.py

@@ -316,8 +316,14 @@ class LoadParams:
         return fields_with_data or []
 
     def __str__(self) -> str:
-        size, unit = calc_unit(self.object_size, 1)
-        static_params = [f"{self.scenario.value} ({size:.4g} {unit})"]
+        load_type_str = self.scenario.value if self.scenario else self.load_type.value
+        # TODO: migrate load_params defaults to testlib
+        if self.object_size is not None:
+            size, unit = calc_unit(self.object_size, 1)
+            static_params = [f"{load_type_str} ({size:.4g} {unit})"]
+        else:
+            static_params = [f"{load_type_str}"]
+
         dynamic_params = [
             f"{meta_field.name}={meta_field.value}"
             for meta_field in self._get_applicable_fields()

src/frostfs_testlib/storage/controllers/background_load_controller.py

@@ -53,10 +53,6 @@ class BackgroundLoadController:
         if load_params.endpoint_selection_strategy is None:
             raise RuntimeError("endpoint_selection_strategy should not be None")
 
-        self.endpoints = self._get_endpoints(
-            load_params.load_type, load_params.endpoint_selection_strategy
-        )
-
     @run_optionally(optionals.OPTIONAL_BACKGROUND_LOAD_ENABLED, [])
     def _get_endpoints(
         self, load_type: LoadType, endpoint_selection_strategy: EndpointSelectionStrategy
@@ -100,6 +96,9 @@ class BackgroundLoadController:
     @run_optionally(optionals.OPTIONAL_BACKGROUND_LOAD_ENABLED)
     @reporter.step_deco("Prepare load instances")
     def prepare(self):
+        self.endpoints = self._get_endpoints(
+            self.load_params.load_type, self.load_params.endpoint_selection_strategy
+        )
         self.runner.prepare(self.load_params, self.nodes_under_load, self.k6_dir)
         self.runner.init_k6_instances(self.load_params, self.endpoints, self.k6_dir)
 
@@ -204,3 +203,9 @@ class BackgroundLoadController:
     def _get_results(self) -> dict:
         with reporter.step(f"Get {self.load_params.scenario.value} scenario results"):
             return self.runner.get_results()
+
+    def __str__(self) -> str:
+        return self.load_params.__str__()
+
+    def __repr__(self) -> str:
+        return repr(self.load_params)

tests/test_load_config.py

@@ -3,7 +3,17 @@ from typing import Any, get_args
 
 import pytest
 
-from frostfs_testlib.load.load_config import LoadParams, LoadScenario, LoadType, Preset
+from frostfs_testlib.load.load_config import (
+    EndpointSelectionStrategy,
+    LoadParams,
+    LoadScenario,
+    LoadType,
+    Preset,
+)
+from frostfs_testlib.storage.cluster import ClusterNode
+from frostfs_testlib.storage.controllers.background_load_controller import BackgroundLoadController
+from frostfs_testlib.storage.dataclasses.frostfs_services import StorageNode
+from frostfs_testlib.storage.dataclasses.node_base import NodeBase
 
 
 @dataclass
@@ -36,7 +46,10 @@ class TestLoadConfig:
         return self._get_filled_load_params(load_type, load_scenario, set_empty)
 
     def test_load_params_only_load_type_required(self):
-        LoadParams(load_type=LoadType.S3)
+        load_params = LoadParams(load_type=LoadType.S3)
+        expected = "load: s3"
+        assert repr(load_params) == expected
+        assert f"{load_params}" == expected
 
     def test_load_params_initially_have_all_values_none(self):
         load_params = LoadParams(load_type=LoadType.S3)
@@ -60,6 +73,17 @@ class TestLoadConfig:
         assert f"{load_params}" == expected
         assert repr(load_params) == expected
 
+    @pytest.mark.parametrize("load_params", [LoadScenario.gRPC], indirect=True)
+    def test_load_controller_string_representation(self, load_params: LoadParams):
+        load_params.endpoint_selection_strategy = EndpointSelectionStrategy.ALL
+        load_params.object_size = 512
+        background_load_controller = BackgroundLoadController(
+            "tmp", load_params, "wallet", None, None
+        )
+        expected = "load: grpc (512 KiB), writers=7, readers=7, deleters=8"
+        assert f"{background_load_controller}" == expected
+        assert repr(background_load_controller) == expected
+
     def test_load_set_id_changes_fields(self):
         load_params = LoadParams(load_type=LoadType.S3)
         load_params.preset = Preset()