Regression/diff testing — compare API responses between environments.

Runs the same test plan against two environments (e.g. staging vs production) and reports differences in responses: body changes, new/missing fields, status code changes, header differences.

Example

use momus_diff::{DiffConfig, run_diff};
use momus_core::ast::TestPlan;

let plan: TestPlan = serde_json::from_str(r#"{"name":"test","base_url":"http://localhost","steps":[]}"#).unwrap();
let config = DiffConfig {
    baseline_url: "https://api-v1.example.com".into(),
    target_url: "https://api-v2.example.com".into(),
    ..Default::default()
};
let report = run_diff(&plan, &config).await.unwrap();
println!("Changes: {} added, {} removed, {} modified", report.fields_added, report.fields_removed, report.fields_modified);