coach/player provider split + add OpenAI

Allows coach and player LLM providers to be separately specified.
Also adds OpenAI provider

crates/g3-config/src/tests.rs

@@ -0,0 +1,131 @@
+#[cfg(test)]
+mod tests {
+    use crate::Config;
+    use std::fs;
+    use tempfile::TempDir;
+
+    #[test]
+    fn test_coach_player_providers() {
+        // Create a temporary directory for the test config
+        let temp_dir = TempDir::new().unwrap();
+        let config_path = temp_dir.path().join("test_config.toml");
+        
+        // Write a test configuration with coach and player providers
+        let config_content = r#"
+[providers]
+default_provider = "databricks"
+coach = "anthropic"
+player = "embedded"
+
+[providers.databricks]
+host = "https://test.databricks.com"
+token = "test-token"
+model = "test-model"
+
+[providers.anthropic]
+api_key = "test-key"
+model = "claude-3"
+
+[providers.embedded]
+model_path = "test.gguf"
+model_type = "llama"
+
+[agent]
+max_context_length = 8192
+enable_streaming = true
+timeout_seconds = 60
+"#;
+        
+        fs::write(&config_path, config_content).unwrap();
+        
+        // Load the configuration
+        let config = Config::load(Some(config_path.to_str().unwrap())).unwrap();
+        
+        // Test that the providers are correctly identified
+        assert_eq!(config.providers.default_provider, "databricks");
+        assert_eq!(config.get_coach_provider(), "anthropic");
+        assert_eq!(config.get_player_provider(), "embedded");
+        
+        // Test creating coach config
+        let coach_config = config.for_coach().unwrap();
+        assert_eq!(coach_config.providers.default_provider, "anthropic");
+        
+        // Test creating player config
+        let player_config = config.for_player().unwrap();
+        assert_eq!(player_config.providers.default_provider, "embedded");
+    }
+    
+    #[test]
+    fn test_coach_player_fallback_to_default() {
+        // Create a temporary directory for the test config
+        let temp_dir = TempDir::new().unwrap();
+        let config_path = temp_dir.path().join("test_config.toml");
+        
+        // Write a test configuration WITHOUT coach and player providers
+        let config_content = r#"
+[providers]
+default_provider = "databricks"
+
+[providers.databricks]
+host = "https://test.databricks.com"
+token = "test-token"
+model = "test-model"
+
+[agent]
+max_context_length = 8192
+enable_streaming = true
+timeout_seconds = 60
+"#;
+        
+        fs::write(&config_path, config_content).unwrap();
+        
+        // Load the configuration
+        let config = Config::load(Some(config_path.to_str().unwrap())).unwrap();
+        
+        // Test that coach and player fall back to default provider
+        assert_eq!(config.get_coach_provider(), "databricks");
+        assert_eq!(config.get_player_provider(), "databricks");
+        
+        // Test creating coach config (should use default)
+        let coach_config = config.for_coach().unwrap();
+        assert_eq!(coach_config.providers.default_provider, "databricks");
+        
+        // Test creating player config (should use default)
+        let player_config = config.for_player().unwrap();
+        assert_eq!(player_config.providers.default_provider, "databricks");
+    }
+    
+    #[test]
+    fn test_invalid_provider_error() {
+        // Create a temporary directory for the test config
+        let temp_dir = TempDir::new().unwrap();
+        let config_path = temp_dir.path().join("test_config.toml");
+        
+        // Write a test configuration with an unconfigured provider
+        let config_content = r#"
+[providers]
+default_provider = "databricks"
+coach = "openai"  # OpenAI is not configured
+
+[providers.databricks]
+host = "https://test.databricks.com"
+token = "test-token"
+model = "test-model"
+
+[agent]
+max_context_length = 8192
+enable_streaming = true
+timeout_seconds = 60
+"#;
+        
+        fs::write(&config_path, config_content).unwrap();
+        
+        // Load the configuration
+        let config = Config::load(Some(config_path.to_str().unwrap())).unwrap();
+        
+        // Test that trying to create a coach config with unconfigured provider fails
+        let result = config.for_coach();
+        assert!(result.is_err());
+        assert!(result.unwrap_err().to_string().contains("not configured"));
+    }
+}