diff --git a/robot/resources/lib/python/utility_keywords.py b/robot/resources/lib/python/utility_keywords.py
index 1602e1a..e6a3ccc 100644
--- a/robot/resources/lib/python/utility_keywords.py
+++ b/robot/resources/lib/python/utility_keywords.py
@@ -16,16 +16,15 @@ from robot.libraries.BuiltIn import BuiltIn
 ROBOT_AUTO_KEYWORDS = False
 
 @keyword('Generate file')
-def generate_file_and_file_hash(size: str) -> str:
+def generate_file_and_file_hash(size: int) -> str:
     """
     Function generates a big binary file with the specified size in bytes and its hash.
     Args:
-        size (str): the size in bytes, can be declared as 6e+6 for example
+        size (int): the size in bytes, can be declared as 6e+6 for example
     Returns:
         (str): the path to the generated file
         (str): the hash of the generated file
     """
-    size = int(float(size))
     filename = f"{os.getcwd()}/{ASSETS_DIR}/{str(uuid.uuid4())}"
     with open(filename, 'wb') as fout:
         fout.write(os.urandom(size))
diff --git a/robot/testsuites/integration/services/s3_gate_bucket.robot b/robot/testsuites/integration/services/s3_gate_bucket.robot
index 78bb753..030fd6c 100644
--- a/robot/testsuites/integration/services/s3_gate_bucket.robot
+++ b/robot/testsuites/integration/services/s3_gate_bucket.robot
@@ -5,6 +5,7 @@ Library     Collections
 Library     OperatingSystem
 
 Library     neofs.py
+Library     container.py
 Library     s3_gate.py
 Library     contract_keywords.py
 Library     utility_keywords.py
@@ -33,7 +34,7 @@ Buckets in NeoFS S3 Gateway
     ...  ${SEC_ACCESS_KEY}
     ...  ${OWNER_PRIV_KEY} =    Init S3 Credentials    ${WALLET}
 
-    ${CONTEINERS_LIST} =        Container List               ${WIF}
+    @{CONTEINERS_LIST} =        List Containers               ${WALLET}
                                 List Should Contain Value    ${CONTEINERS_LIST}    ${CID}
 
     ${S3_CLIENT} =              Config S3 client    ${ACCESS_KEY_ID}    ${SEC_ACCESS_KEY}
diff --git a/robot/variables/common.py b/robot/variables/common.py
index d350d58..3f079e5 100644
--- a/robot/variables/common.py
+++ b/robot/variables/common.py
@@ -11,8 +11,8 @@ CONTAINER_WAIT_INTERVAL = "1m"
 NEOFS_EPOCH_TIMEOUT = (os.getenv("NEOFS_EPOCH_TIMEOUT") if os.getenv("NEOFS_EPOCH_TIMEOUT")
                   else os.getenv("NEOFS_IR_TIMERS_EPOCH", "300s"))
 
-SIMPLE_OBJ_SIZE = "1000"
-COMPLEX_OBJ_SIZE = "2000"
+SIMPLE_OBJ_SIZE = 1000
+COMPLEX_OBJ_SIZE = 2000
 
 MAINNET_BLOCK_TIME = os.getenv('MAINNET_BLOCK_TIME', "1s")
 MAINNET_TIMEOUT = os.getenv('MAINNET_TIMEOUT', "1min")