refactor(env.py): streamline environment-specific value retrieval

Introduce a helper method `_get_env_specific_value` to reduce code
duplication when fetching environment-specific configuration values.
This change simplifies the logic in `get_database_url` and
`get_bot_token` by centralizing the error handling and key selection
process. Additionally, adjust the workspace root determination logic
to handle different directory structures, ensuring the correct root
path is set in various scenarios. This refactoring enhances code
maintainability and readability by reducing redundancy and improving
clarity.

Author: kzndotsh

tux/utils/env.py

@@ -59,6 +59,12 @@ def __init__(self, dotenv_path: Path | None = None, load_env: bool = True):
         """
         # Core paths
         self.workspace_root = Path(__file__).parent.parent.parent
+        if self.workspace_root.name == "tux":
+            # If we're in the tux package, this is the workspace root
+            pass
+        elif self.workspace_root.parent.name == "tux":
+            # If we're in tests/tux, go up one more level
+            self.workspace_root = self.workspace_root.parent
         self.dotenv_path = dotenv_path or self.workspace_root / ".env"
 
         # Load environment variables
@@ -128,6 +134,40 @@ def set(self, key: str, value: Any, persist: bool = False) -> None:
         if persist and self.dotenv_path.exists():
             set_key(self.dotenv_path, key, str(value))
 
+    def _get_env_specific_value(self, env: Environment, dev_key: str, prod_key: str, value_name: str) -> str:
+        """
+        Get environment-specific configuration value.
+
+        Parameters
+        ----------
+        env : Environment
+            The environment to get value for
+        dev_key : str
+            Environment variable key for development
+        prod_key : str
+            Environment variable key for production
+        value_name : str
+            Human-readable name for error messages
+
+        Returns
+        -------
+        str
+            Configuration value
+
+        Raises
+        ------
+        ConfigurationError
+            If value is not configured for environment
+        """
+        key = dev_key if env.is_dev else prod_key
+        value = self.get(key)  # Don't provide a default value
+
+        if value is None:
+            error_msg = f"No {value_name} found for the {env.value.upper()} environment."
+            raise ConfigurationError(error_msg)
+
+        return value
+
     def get_database_url(self, env: Environment) -> str:
         """
         Get database URL for specified environment.
@@ -147,17 +187,7 @@ def get_database_url(self, env: Environment) -> str:
         ConfigurationError
             If database URL is not configured for environment
         """
-        # Get the appropriate database URL key based on the environment
-        key = "DEV_DATABASE_URL" if env.is_dev else "PROD_DATABASE_URL"
-        url = self.get(key, default="")
-
-        if not url:
-            # If no URL is found, raise an error.
-            # We no longer provide a default/mock URL here.
-            error_msg = f"No database URL found for the {env.value.upper()} environment."
-            raise ConfigurationError(error_msg)
-
-        return url
+        return self._get_env_specific_value(env, "DEV_DATABASE_URL", "PROD_DATABASE_URL", "database URL")
 
     def get_bot_token(self, env: Environment) -> str:
         """
@@ -178,16 +208,7 @@ def get_bot_token(self, env: Environment) -> str:
         ConfigurationError
             If bot token is not configured for environment
         """
-        # Get the appropriate bot token key based on the environment
-        key = "DEV_BOT_TOKEN" if env.is_dev else "PROD_BOT_TOKEN"
-        token = self.get(key, default="")
-
-        if not token:
-            # If no token is found, raise an error.
-            error_msg = f"No bot token found for the {env.value.upper()} environment."
-            raise ConfigurationError(error_msg)
-
-        return token
+        return self._get_env_specific_value(env, "DEV_BOT_TOKEN", "PROD_BOT_TOKEN", "bot token")
 
 
 class EnvironmentManager:
@@ -200,22 +221,22 @@ class EnvironmentManager:
 
     _instance = None
 
+    @classmethod
+    def reset_for_testing(cls) -> None:
+        """Reset the singleton instance for testing purposes."""
+        cls._instance = None
+
     def __new__(cls, *args: Any, **kwargs: Any) -> "EnvironmentManager":
-        """Create or return the singleton instance."""
+        """Ensure singleton pattern."""
         if cls._instance is None:
             cls._instance = super().__new__(cls)
-            cls._instance._initialized = False
         return cls._instance
 
     def __init__(self) -> None:
-        """Initialize the environment manager if not already initialized."""
-        if getattr(self, "_initialized", False):
-            return
-
-        # Core configuration
-        self._environment = Environment.DEVELOPMENT  # Default to development
-        self._config = Config()
-        self._initialized = True
+        """Initialize environment manager."""
+        if not hasattr(self, "_environment"):
+            self._environment = Environment.DEVELOPMENT
+            self._config = Config()
 
     @property
     def environment(self) -> Environment: