test: add test for missing error paths in load_client_config (#19)

.changeset/testing-improvement.md

@@ -0,0 +1,5 @@
+---
+"@googleworkspace/cli": patch
+---
+
+Add test for missing error path in load_client_config

src/auth_commands.rs

@@ -44,6 +44,11 @@ const READONLY_SCOPES: &[&str] = &[
 ];
 
 pub fn config_dir() -> PathBuf {
+    #[cfg(test)]
+    if let Ok(dir) = std::env::var("GOOGLE_WORKSPACE_CLI_CONFIG_DIR") {
+        return PathBuf::from(dir);
+    }
+
     dirs::config_dir()
         .unwrap_or_else(|| PathBuf::from("."))
         .join("gws")

src/oauth_config.rs

@@ -199,4 +199,65 @@ mod tests {
         let result = serde_json::from_str::<ClientSecretFile>(json);
         assert!(result.is_err());
     }
+
+    // Helper to manage the env var safely and clean up automatically
+    struct EnvGuard {
+        key: String,
+        original_value: Option<String>,
+    }
+
+    impl EnvGuard {
+        fn new(key: &str, value: &str) -> Self {
+            let original_value = std::env::var(key).ok();
+            std::env::set_var(key, value);
+            Self {
+                key: key.to_string(),
+                original_value,
+            }
+        }
+    }
+
+    impl Drop for EnvGuard {
+        fn drop(&mut self) {
+            if let Some(val) = &self.original_value {
+                std::env::set_var(&self.key, val);
+            } else {
+                std::env::remove_var(&self.key);
+            }
+        }
+    }
+
+    #[test]
+    #[serial_test::serial]
+    fn test_load_client_config() {
+        let dir = tempfile::tempdir().unwrap();
+        let _env_guard = EnvGuard::new(
+            "GOOGLE_WORKSPACE_CLI_CONFIG_DIR",
+            dir.path().to_str().unwrap(),
+        );
+
+        // Initially no config file exists
+        let result = load_client_config();
+        let err = result.unwrap_err();
+        assert!(err.to_string().contains("Cannot read"));
+
+        // Create a valid config file
+        save_client_config("test-id", "test-secret", "test-project").unwrap();
+
+        // Now loading should succeed
+        let config = load_client_config().unwrap();
+        assert_eq!(config.client_id, "test-id");
+        assert_eq!(config.client_secret, "test-secret");
+        assert_eq!(config.project_id, "test-project");
+
+        // Create an invalid config file
+        let path = client_config_path();
+        std::fs::write(&path, "invalid json").unwrap();
+
+        let result = load_client_config();
+        let err = result.unwrap_err();
+        assert!(err
+            .to_string()
+            .contains("Invalid client_secret.json format"));
+    }
 }