运行behave命令触发HOOK-ERROR：before_all中出现KeyError: 'environment'

Let's break down why you're hitting this error and walk through fixes step by step.

First, let's align on your setup:

• You have a behave.ini in your project root with [behave.userdata] environment = int
• Your environment.py tries to access userdata['environment'], but the output shows an empty dict {} before throwing the KeyError

Common Causes & Solutions #

1. Behave isn't reading your behave.ini file

This is the most likely issue. Let's verify this first:

• Run this command from your project root:

  behave --show-userdata
  

  If you don't see environment: int in the output, Behave isn't picking up your config. Double-check:
  • Is behave.ini exactly in your project root (same level as the features folder)?
  • Does the ini section have no typos? It must be [behave.userdata] (no extra spaces, correct spelling).
  • Are you running the behave command from the project root? If you run it from a subfolder, Behave will look for the ini file there instead.

2. You're accidentally disabling user data

If you added the --no-userdata flag to your behave command, it will ignore all userdata configs (including the ini file). Remove that flag and try again.

3. Outdated Behave version

Older Behave versions had bugs with ini file parsing. Upgrade to the latest version to rule this out:

pip install --upgrade behave

4. Fallback: Pass userdata via command line

If the ini file still isn't working, bypass it entirely by passing the environment directly when running Behave:

behave -D environment=int

Run this and check if your userdata dict now includes the environment key.

Robust Code to Prevent Future KeyErrors #

Even once you fix the config issue, make your code more resilient. Instead of accessing the key directly, use dict.get() to handle missing keys gracefully:

def before_all(context):
    userdata = context.config.userdata
    print(userdata)
    # Use get() with a fallback value to avoid KeyError
    environment = userdata.get('environment', 'default')  # 'default' kicks in if the key is missing
    print(environment)

Final Quick Checks #

• Ensure no environment variables are overriding your config (like BEHAVE_USERDATA_environment set to an unexpected value)
• Confirm your environment.py is in the features/ folder (not nested in steps/ or another subfolder)

内容的提问来源于stack exchange，提问作者Satish Michael