Fix failing integration tests for governance and transaction endpoints

Update governance test fixtures to use valid mainnet DRep and proposal
IDs that exist on-chain. Fix transaction submit test to check status_code
instead of removed error string. Update evaluate_cbor test to match new
Ogmios response structure with ScriptFailures nesting.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: semsorock

tests/test_cardano_governance.py

@@ -2,9 +2,11 @@
 from blockfrost import BlockFrostApi, ApiError
 from blockfrost.utils import convert_json_to_object
 
-drep_id = 'drep1mvdu8slennngja7w4un6knwezufra70887zuxpprd64jxfveahn'
-tx_hash = 'f5ca33220afcc0340d1fa3cba9b0e1f3c3c6e1eab57d688ed700ae56bbce9170'
+drep_id = 'drep1yfaaaaa270yjt6tu5skndugekprf5ykv5jshanl0c6gqx5qpstskf'
+tx_hash = '51f495aa23f4b3b3aa90afde4a0e67823bb7ac4ac65f5ffbb138373b863f2f74'
 cert_index = 0
+# proposal with metadata (treasury_withdrawals type)
+metadata_tx_hash = '60ed6ab43c840ff888a8af30a1ed27b41e9f4a91a89822b2b63d1bfc52aeec45'
 
 
 def test_governance_dreps(requests_mock):
@@ -265,4 +267,4 @@ def test_governance_proposal_metadata(requests_mock):
 def test_integration_governance_proposal_metadata():
     if os.getenv('BLOCKFROST_PROJECT_ID_MAINNET'):
         api = BlockFrostApi(project_id=os.getenv('BLOCKFROST_PROJECT_ID_MAINNET'))
-        api.governance_proposal_metadata(tx_hash=tx_hash, cert_index=cert_index)
+        api.governance_proposal_metadata(tx_hash=metadata_tx_hash, cert_index=cert_index)

tests/test_cardano_transactions.py

@@ -412,7 +412,7 @@ def test_integration_transaction_submit_cbor():
 
         with pytest.raises(ApiError) as exc_info:
             api.transaction_submit_cbor(tx_cbor=tx_cbor)
-        assert exc_info.value.message.find("transaction submit error") > -1
+        assert exc_info.value.status_code == 400
         # Make sure that the tx cbor was correctly passed
         assert exc_info.value.message.find(
             "54bcb22a31a100080ffbf7edbac538b1517d99fa85ec77bfac089ab8249e2708") > -1
@@ -443,7 +443,8 @@ def test_integration_transaction_evaluate_cbor():
         # }
 
         # Response with an ogmios error about missing input
-        assert result.result.EvaluationFailure.CannotCreateEvaluationContext.reason.find(
+        script_failure = getattr(result.result.EvaluationFailure.ScriptFailures, 'spend:0')
+        assert script_failure.CannotCreateEvaluationContext.reason.find(
             'Unknown transaction input') > -1