features/steps/cli_main_cov3_steps.py

@@ -31,15 +31,32 @@ def step_reset_subcommands_flag(context: Any) -> None:
 
 @when("cmcov3 _register_subcommands is called and an import raises an error")
 def step_register_subcommands_import_error(context: Any) -> None:
-    """Patch a subcommand import so _register_subcommands hits its except block."""
+    """Patch a subcommand import so _register_subcommands hits its except block.
+
+    Also evicts cleveragents.cli.commands and all its sub-packages from
+    sys.modules so the __import__ patch actually takes effect — the module is
+    normally cached from the eager _register_subcommands() call at import time.
+    """
+    import sys
     import builtins
 
     mod = context.cmcov3_mod
     mock_err_console = MagicMock()
     original_import = builtins.__import__
 
+    # Evict cleveragents.cli.commands and all its sub-packages/modules from
+    # sys.modules so the __import__ patch takes effect.
+    module_name = "cleveragents.cli.commands"
+    original_modules = {
+        key: sys.modules[key]
+        for key in list(sys.modules)
+        if key == module_name or key.startswith(module_name + ".")
+    }
+    for key in original_modules:
+        del sys.modules[key]
+
     def failing_import(name: str, *args: Any, **kwargs: Any) -> Any:
-        if name == "cleveragents.cli.commands":
+        if name == module_name:
             raise ImportError("cmcov3 forced import failure")
         return original_import(name, *args, **kwargs)
 
@@ -51,13 +68,18 @@ def step_register_subcommands_import_error(context: Any) -> None:
 
     patcher_builtins = patch.object(builtins, "__import__", side_effect=failing_import)
     patcher_builtins.start()
+    context.add_cleanup(patcher_builtins.stop)
 
+    # Use BaseException to also catch SystemExit which is raised by
+    # _register_subcommands() on import failure (SystemExit extends
+    # BaseException, not Exception, so except Exception would not catch it).
     try:
         mod._register_subcommands()
-    except Exception as exc:
+    except BaseException as exc:
         context.cmcov3_error = exc
-    finally:
-        patcher_builtins.stop()
+
+    # Restore original sys.modules entries for other scenarios.
+    context.add_cleanup(lambda: sys.modules.update(original_modules))
 
     context.cmcov3_err_console = mock_err_console