Run the plugin as early as possible

This is required when other plugins (e.g. pytest-django) need to access environment variables set by this plugin.

Fixes #3.

Author: Schnouki

pytest_env/plugin.py

@@ -1,5 +1,7 @@
 import os
 
+import pytest
+
 
 def pytest_addoption(parser):
     parser.addini("env",
@@ -8,6 +10,7 @@ def pytest_addoption(parser):
                   default=[])
 
 
+@pytest.hookimpl(tryfirst=True)
 def pytest_load_initial_conftests(args, early_config, parser):
     for e in early_config.getini("env"):
         part = e.partition("=")