diff --git a/integration-tests/tests/add.wasm b/integration-tests/tests/add.wasm
deleted file mode 100644
index 6f306d39f6f..00000000000
Binary files a/integration-tests/tests/add.wasm and /dev/null differ
diff --git a/integration-tests/tests/singlepass_crash.wasm b/integration-tests/tests/singlepass_crash.wasm
deleted file mode 100644
index 778ec394a7a..00000000000
Binary files a/integration-tests/tests/singlepass_crash.wasm and /dev/null differ
diff --git a/pytest/testdata/hello.wasm b/pytest/testdata/hello.wasm
deleted file mode 100644
index 10d1e721581..00000000000
Binary files a/pytest/testdata/hello.wasm and /dev/null differ
diff --git a/pytest/tests/sanity/rpc_light_client_execution_outcome_proof.py b/pytest/tests/sanity/rpc_light_client_execution_outcome_proof.py
index de2d2a6884f..44d3662c532 100644
--- a/pytest/tests/sanity/rpc_light_client_execution_outcome_proof.py
+++ b/pytest/tests/sanity/rpc_light_client_execution_outcome_proof.py
@@ -3,14 +3,15 @@
 # the transaction and receipts execution outcome proof for
 # light client works
 
-import sys
 import base58, base64
-import json
 import hashlib
+import json
+import struct
+import sys
 
 sys.path.append('lib')
 from cluster import start_cluster, Key
-from utils import load_binary_file, compute_merkle_root_from_path
+from utils import load_test_contract, compute_merkle_root_from_path
 from serializer import BinarySerializer
 import transaction
 import time
@@ -113,36 +114,15 @@ def serialize_execution_outcome_with_id(outcome, id):
     return borsh_res
 
 
-nodes = start_cluster(
-    2, 0, 1, None,
-    [["epoch_length", 1000], ["block_producer_kickout_threshold", 80]], {}
-)
-
-# deploy a smart contract for testing
-contract_key = nodes[0].signer_key
-hello_smart_contract = load_binary_file('testdata/hello.wasm')
-
-status = nodes[0].get_status()
-latest_block_hash = status['sync_info']['latest_block_hash']
-deploy_contract_tx = transaction.sign_deploy_contract_tx(
-    contract_key, hello_smart_contract, 10,
-    base58.b58decode(latest_block_hash.encode('utf8')))
-deploy_contract_response = nodes[0].send_tx_and_wait(deploy_contract_tx, 15)
-assert 'error' not in deploy_contract_response, deploy_contract_response
-
-
-def check_transaction_outcome_proof(should_succeed, nonce):
+def check_transaction_outcome_proof(nodes, should_succeed, nonce):
     status = nodes[1].get_status()
     latest_block_hash = status['sync_info']['latest_block_hash']
     function_caller_key = nodes[0].signer_key
     gas = 300000000000000 if should_succeed else 1000
 
     function_call_1_tx = transaction.sign_function_call_tx(
-        function_caller_key, contract_key.account_id, 'setKeyValue',
-        json.dumps({
-            "key": "my_key",
-            "value": "my_value"
-        }).encode('utf-8'), gas, 100000000000, nonce,
+        function_caller_key, nodes[0].signer_key.account_id, 'write_key_value',
+        struct.pack('<QQ', 42, 10), gas, 100000000000, nonce,
         base58.b58decode(latest_block_hash.encode('utf8')))
     function_call_result = nodes[1].send_tx_and_wait(function_call_1_tx, 15)
     assert 'error' not in function_call_result
@@ -204,5 +184,19 @@ def check_transaction_outcome_proof(should_succeed, nonce):
                                     'block_merkle_root']) == block_merkle_root, f'expected block merkle root {light_client_block["inner_lite"]["block_merkle_root"]} actual {base58.b58encode(block_merkle_root)}'
 
 
-check_transaction_outcome_proof(True, 20)
-check_transaction_outcome_proof(False, 30)
+def test_outcome_proof():
+    nodes = start_cluster(
+        2, 0, 1, None,
+        [["epoch_length", 1000], ["block_producer_kickout_threshold", 80]], {}
+    )
+
+    status = nodes[0].get_status()
+    latest_block_hash = status['sync_info']['latest_block_hash']
+    deploy_contract_tx = transaction.sign_deploy_contract_tx(
+        nodes[0].signer_key, load_test_contract(), 10,
+        base58.b58decode(latest_block_hash.encode('utf8')))
+    deploy_contract_response = nodes[0].send_tx_and_wait(deploy_contract_tx, 15)
+    assert 'error' not in deploy_contract_response, deploy_contract_response
+
+    check_transaction_outcome_proof(nodes, True, 20)
+    check_transaction_outcome_proof(nodes, False, 30)
diff --git a/pytest/tests/sanity/rpc_state_changes.py b/pytest/tests/sanity/rpc_state_changes.py
index 7088439b96e..2f169f573d4 100644
--- a/pytest/tests/sanity/rpc_state_changes.py
+++ b/pytest/tests/sanity/rpc_state_changes.py
@@ -2,9 +2,10 @@
 # and call various scenarios to trigger store changes.
 # Check that the key changes are observable via `changes` RPC call.
 
-import sys
 import base58, base64
 import json
+import struct
+import sys
 import threading
 
 import deepdiff
@@ -12,7 +13,7 @@
 sys.path.append('lib')
 from cluster import start_cluster
 from key import Key
-from utils import load_binary_file
+from utils import load_test_contract
 import transaction
 
 nodes = start_cluster(
@@ -325,18 +326,18 @@ def test_key_value_changes():
     1. Deploy a contract.
     2. Observe the code changes in the block where the transaction outcome "lands".
     3. Send two transactions to be included into the same block setting and overriding the value of
-       the same key (`my_key`).
+       the same key.
     4. Observe the changes in the block where the transaction outcome "lands".
     """
 
     contract_key = nodes[0].signer_key
-    hello_smart_contract = load_binary_file('testdata/hello.wasm')
+    contract_blob = load_test_contract()
 
     # Step 1
     status = nodes[0].get_status()
     latest_block_hash = status['sync_info']['latest_block_hash']
     deploy_contract_tx = transaction.sign_deploy_contract_tx(
-        contract_key, hello_smart_contract, 10,
+        contract_key, contract_blob, 10,
         base58.b58decode(latest_block_hash.encode('utf8')))
     deploy_contract_response = nodes[0].send_tx_and_wait(deploy_contract_tx, 10)
 
@@ -401,7 +402,7 @@ def test_key_value_changes():
                 "account_id":
                     contract_key.account_id,
                 "code_base64":
-                    base64.b64encode(hello_smart_contract).decode('utf-8'),
+                    base64.b64encode(contract_blob).decode('utf-8'),
             }
         },]
     }
@@ -429,40 +430,37 @@ def test_key_value_changes():
     latest_block_hash = status['sync_info']['latest_block_hash']
     function_caller_key = nodes[0].signer_key
 
-    def set_value_1():
-        function_call_1_tx = transaction.sign_function_call_tx(
-            function_caller_key, contract_key.account_id, 'setKeyValue',
-            json.dumps({
-                "key": "my_key",
-                "value": "my_value_1"
-            }).encode('utf-8'), 300000000000000, 100000000000, 20,
-            base58.b58decode(latest_block_hash.encode('utf8')))
-        nodes[1].send_tx_and_wait(function_call_1_tx, 10)
-
-    function_call_1_thread = threading.Thread(target=set_value_1)
-    function_call_1_thread.start()
-
-    function_call_2_tx = transaction.sign_function_call_tx(
-        function_caller_key, contract_key.account_id, 'setKeyValue',
-        json.dumps({
-            "key": "my_key",
-            "value": "my_value_2"
-        }).encode('utf-8'), 300000000000000, 100000000000, 30,
-        base58.b58decode(latest_block_hash.encode('utf8')))
-    function_call_2_response = nodes[1].send_tx_and_wait(function_call_2_tx, 10)
-    assert function_call_2_response['result']['receipts_outcome'][0]['outcome']['status'] == {'SuccessValue': ''}, \
-        "Expected successful execution, but the output was: %s" % function_call_2_response
-    function_call_1_thread.join()
+    key = struct.pack('<Q', 42)
+    key_base64 = base64.b64encode(key).decode('ascii')
 
-    tx_block_hash = function_call_2_response['result']['transaction_outcome'][
-        'block_hash']
+    def set_value(value, *, nounce):
+        args = key + struct.pack('<Q', value)
+        tx = transaction.sign_function_call_tx(
+            function_caller_key, contract_key.account_id,
+            'write_key_value', args, 300000000000000, 100000000000, nounce,
+            base58.b58decode(latest_block_hash.encode('utf8')))
+        response = nodes[1].send_tx_and_wait(tx, 10)
+        try:
+            status = response['result']['receipts_outcome'][0]['outcome'][
+                'status']
+        except (KeyError, IndexError):
+            status = ()
+        assert 'SuccessValue' in status, (
+            "Expected successful execution, but the output was: %s" % response)
+        return response
+
+    thread = threading.Thread(target=lambda: set_value(10, nounce=20))
+    thread.start()
+    response = set_value(20, nounce=30)
+    thread.join()
+
+    tx_block_hash = response['result']['transaction_outcome']['block_hash']
 
     # Step 4
     assert_changes_in_block_response(
         request={"block_id": tx_block_hash},
         expected_response={
-            "block_hash":
-                tx_block_hash,
+            "block_hash": tx_block_hash,
             "changes": [
                 {
                     "type": "account_touched",
@@ -482,7 +480,7 @@ def set_value_1():
     base_request = {
         "block_id": block_hash,
         "changes_type": "data_changes",
-        "key_prefix_base64": base64.b64encode(b"my_key").decode('utf-8'),
+        "key_prefix_base64": key_base64,
     }
     for request in [
             # Test empty account_ids
@@ -502,7 +500,7 @@ def set_value_1():
             **base_request,
             "account_ids": [contract_key.account_id],
             "key_prefix_base64":
-                base64.b64encode(b"my_key_with_extra").decode('utf-8'),
+                base64.b64encode(struct.pack('<Q', 24)).decode('ascii'),
         },
     ]:
         assert_changes_response(request=request,
@@ -513,8 +511,7 @@ def set_value_1():
 
     # Test happy-path
     expected_response = {
-        "block_hash":
-            tx_block_hash,
+        "block_hash": tx_block_hash,
         "changes": [{
             "cause": {
                 "type": "receipt_processing",
@@ -522,22 +519,23 @@ def set_value_1():
             "type": "data_update",
             "change": {
                 "account_id": contract_key.account_id,
-                "key_base64": base64.b64encode(b"my_key").decode('utf-8'),
-                "value_base64": base64.b64encode(b"my_value_1").decode('utf-8'),
+                "key_base64": key_base64,
+                "value_base64": base64.b64encode(
+                    struct.pack('<Q', 10)).decode('ascii'),
             }
         }, {
             "cause": {
                 "type":
                     "receipt_processing",
                 "receipt_hash":
-                    function_call_2_response["result"]["receipts_outcome"][0]
-                    ["id"],
+                    response["result"]["receipts_outcome"][0]["id"],
             },
             "type": "data_update",
             "change": {
                 "account_id": contract_key.account_id,
-                "key_base64": base64.b64encode(b"my_key").decode('utf-8'),
-                "value_base64": base64.b64encode(b"my_value_2").decode('utf-8'),
+                "key_base64": key_base64,
+                "value_base64": base64.b64encode(
+                    struct.pack('<Q', 20)).decode('ascii'),
             }
         }]
     }
@@ -545,7 +543,7 @@ def set_value_1():
     base_request = {
         "block_id": tx_block_hash,
         "changes_type": "data_changes",
-        "key_prefix_base64": base64.b64encode(b"my_key").decode('utf-8'),
+        "key_prefix_base64": key_base64,
     }
     for request in [
         {
@@ -561,12 +559,12 @@ def set_value_1():
         {
             **base_request,
             "account_ids": [contract_key.account_id],
-            "key_prefix_base64": base64.b64encode(b"").decode('utf-8'),
+            "key_prefix_base64": '',
         },
         {
             **base_request,
             "account_ids": [contract_key.account_id],
-            "key_prefix_base64": base64.b64encode(b"my_ke").decode('utf-8'),
+            "key_prefix_base64": base64.b64encode(key[:3]).decode('ascii'),
         },
     ]:
         assert_changes_response(
diff --git a/pytest/tests/sanity/rpc_tx_status.py b/pytest/tests/sanity/rpc_tx_status.py
index 0d6c6bcdc02..a039b091049 100644
--- a/pytest/tests/sanity/rpc_tx_status.py
+++ b/pytest/tests/sanity/rpc_tx_status.py
@@ -1,46 +1,65 @@
-import sys
 import base58
 import json
+import struct
+import sys
 
 sys.path.append('lib')
 from cluster import start_cluster, Key
-from utils import load_binary_file
+from utils import load_test_contract
 import transaction
 
 
-def submit_tx_and_check(node, tx):
+def submit_tx_and_check(nodes, node_index, tx):
+    node = nodes[node_index]
     res = node.send_tx_and_wait(tx, timeout=20)
     assert 'error' not in res, res
 
     tx_hash = res['result']['transaction']['hash']
     query_res = nodes[0].json_rpc('EXPERIMENTAL_tx_status', [tx_hash, 'test0'])
     assert 'error' not in query_res, query_res
-    receipt_id_from_outcomes = set(map(lambda x: x['id'], query_res['result']['receipts_outcome']))
-    receipt_id_from_receipts = set(map(lambda x: x['receipt_id'], query_res['result']['receipts']))
-    is_local_receipt = res['result']['transaction']['signer_id'] == res['result']['transaction']['receiver_id']
+
+    receipt_id_from_outcomes = set(
+        outcome['id'] for outcome in query_res['result']['receipts_outcome'])
+    receipt_id_from_receipts = set(
+        rec['receipt_id'] for rec in query_res['result']['receipts'])
+
+    is_local_receipt = (res['result']['transaction']['signer_id'] ==
+                        res['result']['transaction']['receiver_id'])
     if is_local_receipt:
-        receipt_id_from_outcomes.remove(res['result']['transaction_outcome']['outcome']['receipt_ids'][0])
-    assert receipt_id_from_outcomes == receipt_id_from_receipts, f'receipt id from outcomes {receipt_id_from_outcomes}, receipt id from receipts {receipt_id_from_receipts} '
-
-
-nodes = start_cluster(
-    4, 0, 1, None,
-    [["epoch_length", 1000], ["block_producer_kickout_threshold", 80], ["transaction_validity_period", 10000]], {})
-
-status = nodes[0].get_status()
-block_hash = status['sync_info']['latest_block_hash']
-print("1")
-payment_tx = transaction.sign_payment_tx(nodes[0].signer_key, 'test1', 100, 1,
-                                         base58.b58decode(block_hash.encode('utf8')))
-submit_tx_and_check(nodes[0], payment_tx)
-
-print("2")
-deploy_contract_tx = transaction.sign_deploy_contract_tx(nodes[0].signer_key, load_binary_file('testdata/hello.wasm'), 2, base58.b58decode(block_hash.encode('utf8')))
-submit_tx_and_check(nodes[0], deploy_contract_tx)
-
-print("3")
-function_call_tx = transaction.sign_function_call_tx(nodes[0].signer_key, nodes[0].signer_key.account_id, 'setKeyValue', json.dumps({
-    "key": "my_key",
-    "value": "my_value_1"
-}).encode('utf-8'), 300000000000000, 0, 3, base58.b58decode(block_hash.encode('utf8')))
-submit_tx_and_check(nodes[0], deploy_contract_tx)
+        receipt_id_from_outcomes.remove(
+            res['result']['transaction_outcome']['outcome']['receipt_ids'][0])
+
+    assert receipt_id_from_outcomes == receipt_id_from_receipts, (
+        f'receipt id from outcomes {receipt_id_from_outcomes}, '
+        f'receipt id from receipts {receipt_id_from_receipts}')
+
+
+def test_tx_status():
+    nodes = start_cluster(4, 0, 1, None,
+                          [["epoch_length", 1000],
+                           ["block_producer_kickout_threshold", 80],
+                           ["transaction_validity_period", 10000]],
+                          {})
+
+    signer_key = nodes[0].signer_key
+    status = nodes[0].get_status()
+    block_hash = status['sync_info']['latest_block_hash']
+    encoded_block_hash = base58.b58decode(block_hash.encode('ascii'))
+
+    payment_tx = transaction.sign_payment_tx(
+        signer_key, 'test1', 100, 1, encoded_block_hash)
+    submit_tx_and_check(nodes, 0, payment_tx)
+
+    deploy_contract_tx = transaction.sign_deploy_contract_tx(
+        signer_key, load_test_contract(), 2, encoded_block_hash)
+    submit_tx_and_check(nodes, 0, deploy_contract_tx)
+
+    function_call_tx = transaction.sign_function_call_tx(
+        signer_key, signer_key.account_id,
+        'write_key_value', struct.pack('<QQ', 42, 24),
+        300000000000000, 0, 3, encoded_block_hash)
+    submit_tx_and_check(nodes, 0, deploy_contract_tx)
+
+
+if __name__ == '__main__':
+    test_tx_status()