fix: Flaky test with the FeeEstimationQuery e2e test (#2276)

Signed-off-by: Manish Dait <daitmanish88@gmail.com>

Author: manishdait

tests/integration/fee_estimate_query_e2e_test.py

@@ -1,5 +1,7 @@
 from __future__ import annotations
 
+import time
+
 import pytest
 
 from hiero_sdk_python.account.account_create_transaction import AccountCreateTransaction
@@ -9,15 +11,72 @@
 from hiero_sdk_python.fees.fee_estimate_mode import FeeEstimateMode
 from hiero_sdk_python.file.file_append_transaction import FileAppendTransaction
 from hiero_sdk_python.file.file_id import FileId
+from hiero_sdk_python.hbar import Hbar
 from hiero_sdk_python.query.fee_estimate_query import FeeEstimateQuery
+from hiero_sdk_python.transaction.transfer_transaction import TransferTransaction
+
+
+_fee_estimation_ready = False
+_fee_estimation_error: Exception | None = None
+
+
+# Wait until the mirror_node FeeEstimationService can return a good mock query.
+def wait_for_fee_estimation_service_ready(env):
+    """Wait until the FeeEstimationService is ready."""
+    global _fee_estimation_ready, _fee_estimation_error
+
+    if _fee_estimation_ready:
+        return
+    if _fee_estimation_error:
+        raise _fee_estimation_error
+
+    attempts = 0
+    last_error = None
+
+    print("Waiting for FeeEstimationService to get ready...")
+
+    deadline = time.monotonic() + 600.0
+    while time.monotonic() < deadline:
+        attempts += 1
+        try:
+            probe = (
+                TransferTransaction()
+                .add_hbar_transfer(env.operator_id, Hbar(-1))
+                .add_hbar_transfer(env.operator_id, Hbar(1))
+            )
+
+            FeeEstimateQuery().set_mode(FeeEstimateMode.INTRINSIC).set_transaction(probe).execute(env.client)
+
+            _fee_estimation_ready = True
+
+            print(f"FeeEstimationService ready after {attempts} attempts.")
+            return
+
+        except Exception as e:
+            last_error = e
+            time.sleep(5.0)
+
+    _fee_estimation_error = Exception(
+        f"FeeEstimationService not became ready after {attempts} attempts. Last error: {last_error}"
+    )
+
+    raise _fee_estimation_error
+
+
+def wait_for_sync():
+    """Additional wait to ensure the mirror_node sync."""
+    time.sleep(2.0)
 
 
 @pytest.mark.integration
 def test_can_execute_fee_estimation_query(env):
     """
     Integration test that verifies a fee estimation query executes successfully and returns a non-null result.
     """
+    wait_for_fee_estimation_service_ready(env)
     tx = AccountCreateTransaction().set_key_without_alias(PrivateKey.generate_ed25519()).set_initial_balance(1)
+    wait_for_sync()
+
     query = FeeEstimateQuery().set_transaction(tx)
     result = query.execute(env.client)
 
@@ -29,7 +88,10 @@ def test_can_execute_fee_estimation_query2(env):
     """Integration test that verifies a state-mode fee estimation query
     executes successfully and returns a non-null result.
     """
+    wait_for_fee_estimation_service_ready(env)
     tx = AccountCreateTransaction().set_key_without_alias(PrivateKey.generate_ed25519()).set_initial_balance(1)
+    wait_for_sync()
+
     query = FeeEstimateQuery().set_mode(FeeEstimateMode.STATE).set_transaction(tx)
     result = query.execute(env.client)
 
@@ -41,9 +103,11 @@ def test__fee_estimation_query_chunk_tx_can_execute(env):
     """Integration test that verifies a state-mode fee estimation query executes
     successfully for a chunked file append transaction and returns a non-null result.
     """
+    wait_for_fee_estimation_service_ready(env)
     tx = FileAppendTransaction().set_file_id(FileId(0, 0, 2)).set_chunk_size(10).set_contents("s" * 33)  # 4 chunks
-
     tx.freeze_with(env.client)
+    wait_for_sync()
+
     query = FeeEstimateQuery().set_mode(FeeEstimateMode.STATE).set_transaction(tx)
     result = query.execute(env.client)
 
@@ -55,14 +119,13 @@ def test_can_execute_fee_estimation_query_chunk_tx(env):
     """Integration test that verifies a state-mode fee estimation query executes successfully
     for a chunked topic message submit transaction and returns a non-null result.
     """
+    wait_for_fee_estimation_service_ready(env)
     tx = (
         TopicMessageSubmitTransaction().set_topic_id(TopicId(0, 0, 2)).set_chunk_size(10).set_message("s" * 20)
     )  # 2 chunks
-
-    # 2. IMPORTANT: Let freeze_with generate the valid transaction ID sequence
-    # This ensures tx._transaction_ids is populated correctly.
-
     tx.freeze_with(env.client)
+    wait_for_sync()
+
     query = FeeEstimateQuery().set_mode(FeeEstimateMode.STATE).set_transaction(tx)
     result = query.execute(env.client)