style: remove unused import

- Remove unused pytest import from test_environment.py

Author: tony

tests/test/test_environment.py

@@ -5,8 +5,6 @@
 import os
 import typing as t
 
-import pytest
-
 from libtmux.test.environment import EnvironmentVarGuard
 
 
@@ -116,38 +114,38 @@ def test_environment_var_guard_unset_and_reset() -> None:
 def test_environment_var_guard_exit_with_exception() -> None:
     """Test __exit__ method with exception parameters."""
     env = EnvironmentVarGuard()
-    
+
     # Set up test variables
     os.environ["TEST_VAR"] = "original_value"
     env.set("TEST_VAR", "new_value")
-    
+
     # Call __exit__ with exception parameters
     env.__exit__(
-        t.cast(t.Type[BaseException], RuntimeError),
+        t.cast(type[BaseException], RuntimeError),
         RuntimeError("Test exception"),
         None,
     )
-    
+
     # Verify cleanup still happened
     assert os.environ["TEST_VAR"] == "original_value"
 
 
 def test_environment_var_guard_unset_previously_set() -> None:
     """Test unsetting a variable that was previously set in the same context."""
     env = EnvironmentVarGuard()
-    
+
     # Make sure the variable doesn't exist initially
     if "TEST_NEW_VAR" in os.environ:
         del os.environ["TEST_NEW_VAR"]
-    
+
     # Set a new variable
     env.set("TEST_NEW_VAR", "new_value")
     assert "TEST_NEW_VAR" in os.environ
     assert os.environ["TEST_NEW_VAR"] == "new_value"
-    
+
     # Now unset it - this should hit line 57
     env.unset("TEST_NEW_VAR")
     assert "TEST_NEW_VAR" not in os.environ
-    
+
     # No need to check after cleanup since the variable was never in the environment
     # before we started