Debugging Functional Tests in Bitcoin: Fixing “JSONRPCException: Method not found”
Bitcoin’s functional tests are essential for ensuring the correctness of the blockchain and wallet implementations. However, sometimes these tests fail with a cryptic error message, JSONRPCException: Method not found (-32601). In this article, we’ll go through three common functional tests that failed in your test_runner.py file and provide solutions to resolve the issue.
Test 1: Test_Coins
The Test_Coins test checks if coins are created correctly. It expects a specific method call on the blockchain with the correct input parameters.
Solution
Ensure that the createCoin method is implemented in the blockchain.py file and passed the required arguments (coinName, amount, pubkey) to the expected method call:
blockchain.py
def createCoin(coinName, amount, pubkey):
...
Verify that this implementation matches the test’s expectations.
Test 2: Test_CoinsGetTransaction
The Test_CoinsGetTransaction test checks if a coin transaction is retrieved correctly. It expects a specific method call on the blockchain with the correct input parameters.
Solution
Check that the getTransaction method in the blockchain.py file matches the expected function signature:
blockchain.py
def getTransaction(id):
...
Verify that this implementation meets the test’s expectations. If the solution does not resolve the issue, ensure that the method call is correct and passes the required arguments.
Test 3: Test_Bytes
The Test_Bytes test checks if bytes are transmitted correctly over JSON-RPC. It expects a specific method call on the blockchain with the correct input parameters.
Solution
Verify that the sendBytes method in the blockchain.py file matches the expected function signature:
blockchain.py
def sendBytes(id, data):
...
Ensure that this implementation meets the test’s expectations. If the solution doesn’t resolve the issue, verify that the method call is correct and passes the required arguments.
Additional Tips
- Make sure that all tests are running before attempting to debug the
test_runner.pyfile.
- Use a debugger or print statements to inspect variables and function calls during test execution.
- Consider adding more error checking and logging in your tests to help diagnose issues.
By following these steps, you should be able to identify and fix the issue causing the “JSONRPCException: Method not found” errors in your functional Bitcoin tests.