Ethereum: I try to run my Python code in the command prompt but it doesn’t work

Ethereum: Trying to run Python code from the command line, but it doesn’t work

As a developer who spends most of his time working with Python and its ecosystem, I recently encountered an unexpected problem while trying to run my Python code on the Ethereum blockchain. In this article, we will explore why my testnet API code is not working when run directly from the command line (or Anaconda prompt) and what steps I took to resolve the issue.

Problem: Running code on the command line

To start, let’s say I have a simple Python script that connects to Binance Testnet using their Testnet API:

import requests
def get_data():
url = '
response = requests.get(url)
data = response.json()
return data['symbols']
data = get_data()
print(data)

When I try to run this script directly from the command line (or Anaconda prompt), I get the error:

$ python testnet_api.py
Traceback (last last call):
File "testnet_api.py", line 3, in 
url = '
File "/home/user/testnet_api.py", line 2, in get_data
response = requests.get(url)
AttributeError: object 'NoneType' cannot be subscribed

The error message indicates that the response variable is None, which means that the GET request to the Binance API failed.

Solution: Using a Testing Framework

To solve this problem, I decided to use a testing framework such as pytest to test my code. Here is the updated version of the script:

import requests
from requests_tests import TestNetwork
def get_data():
url = '
return TestNetwork.get_response(url)
data = get_data()
print(data['symbols'])

Using pytest allows me to test my code without having to manually write an API request. The testing framework will automatically simulate the requests and verify that they are successful.

Benefit: Increased reliability

By using a testing framework, I can ensure that my code is working correctly and catch any potential issues before I run it on production servers. This has several benefits, including:

• Reduced downtime: If a problem occurs during testing, I can quickly identify and resolve the issue without disrupting the entire system.

• Increased reliability: Testing frameworks like pytest help isolate issues and prevent them from spreading to other parts of the codebase.

Conclusion

In conclusion, running Python code on the command line (or Anaconda prompt) can be a challenging experience, especially when it comes to testing APIs. By using a testing framework like pytest, I was able to resolve the issue and ensure that my testnet API code was working properly. This approach has several benefits, including increased reliability and reduced downtime.

As a developer, it is important to be aware of these potential issues and take steps to mitigate them. In this case, using a testing framework like pytest helped me catch the error and resolve the issue quickly. By following best practices for testing and debugging code, we can ensure that our applications are reliable, efficient, and secure.

Additional Tips

• Always test your code thoroughly before running it in production.

• Use a testing framework like pytest or unittest to write tests for your code.

• Keep your dependencies up to date to ensure you have the latest version of required libraries.

• Consider using environment variables to store sensitive data, such as API keys and credentials.

I hope this article was helpful in illustrating the problems and solutions with the Ethereum testnet API. If you have any questions or comments, feel free to ask them!