Feature/initialize backend cargo workspace

backend/Cargo.toml

@@ -2,6 +2,8 @@
 name = "predifi-backend"
 version = "0.1.0"
 edition = "2021"
+description = "Axum HTTP backend for the PrediFi platform"
+readme = "README.md"
 
 [[bin]]
 name = "predifi-backend"

backend/README.md

@@ -49,7 +49,7 @@ Verify it is running:
 
 ```bash
 curl http://localhost:3000/           # 200 — welcome message
-curl http://localhost:3000/health     # 200 — {"status":"ok"}
+curl http://localhost:3000/health     # 200 — {"status":"ok","service":"predifi-backend","version":"0.1.0"}
 curl http://localhost:3000/missing    # 404 — unknown route
 ```
 

backend/src/main.rs

@@ -25,9 +25,18 @@ use axum::{routing::get, Json, Router};
 use request_logger::LoggingLayer;
 use serde_json::json;
 
-/// Simple health-check handler — returns `{ "status": "ok" }`.
+/// Health-check handler.
+///
+/// Returns HTTP 200 with basic system info:
+/// - `status`: always `"ok"` when the server is running
+/// - `service`: name of the service
+/// - `version`: current package version from Cargo.toml
 async fn health() -> Json<serde_json::Value> {
-    Json(json!({ "status": "ok" }))
+    Json(json!({
+        "status": "ok",
+        "service": "predifi-backend",
+        "version": env!("CARGO_PKG_VERSION")
+    }))
 }
 
 /// Root handler — returns a welcome message.

backend/src/tests.rs

@@ -1,4 +1,3 @@
-
 #[cfg(test)]
 mod tests {
     use axum::http::{Request, StatusCode};
@@ -66,9 +65,7 @@ mod tests {
         assert_eq!(response.status(), StatusCode::NOT_FOUND);
     }
 
-
     /// Verify the middleware does not alter the status code of a 200 response.
-    /// The middleware is purely observational — it must be transparent to callers.
     #[tokio::test]
     async fn middleware_does_not_alter_200_status() {
         let response = build_router()
@@ -84,7 +81,6 @@ mod tests {
     }
 
     /// Verify the middleware does not alter the status code of a 404 response.
-    /// Same transparency guarantee, but for error responses.
     #[tokio::test]
     async fn middleware_does_not_alter_404_status() {
         let response = build_router()
@@ -122,4 +118,29 @@ mod tests {
             );
         }
     }
-}
+
+    /// GET /health must return basic system info including service and version.
+    #[tokio::test]
+    async fn health_returns_system_info() {
+        let response = build_router()
+            .oneshot(get("/health"))
+            .await
+            .expect("request failed");
+
+        assert_eq!(response.status(), StatusCode::OK);
+
+        let body = body_string(response.into_body()).await;
+        assert!(
+            body.contains("\"service\""),
+            "body should contain a service field, got: {body}"
+        );
+        assert!(
+            body.contains("\"version\""),
+            "body should contain a version field, got: {body}"
+        );
+        assert!(
+            body.contains("predifi-backend"),
+            "body should contain the service name, got: {body}"
+        );
+    }
+}

docs/health-check-endpoint.md

@@ -0,0 +1,62 @@
+# Health Check Endpoint
+
+## Overview
+
+This document describes the health check endpoint implemented in
+`predifi-backend`. It provides a simple way for load balancers,
+orchestrators, and developers to verify the service is running.
+
+---
+
+## Endpoint
+```
+GET /health
+```
+
+### Response
+```json
+{
+  "status": "ok",
+  "service": "predifi-backend",
+  "version": "0.1.0"
+}
+```
+
+- `status` — always `"ok"` when the server is running
+- `service` — name of the service
+- `version` — current version from Cargo.toml
+
+---
+
+## Implementation
+
+**File:** `src/main.rs`
+
+### `health()` handler
+An async Axum handler that returns HTTP 200 with basic system info.
+The version is read at compile time from `Cargo.toml` using
+`env!("CARGO_PKG_VERSION")` — no runtime overhead.
+
+---
+
+## Test Coverage
+
+**File:** `src/tests.rs`
+
+| Test | What it verifies |
+|------|-----------------|
+| `health_returns_200_with_ok_body` | Returns HTTP 200 with status field |
+| `health_returns_system_info` | Returns service name and version |
+| `middleware_does_not_alter_200_status` | Middleware doesn't change 200 response |
+
+---
+
+## Example Usage
+```bash
+curl http://localhost:3000/health
+```
+
+Expected response:
+```json
+{"status":"ok","service":"predifi-backend","version":"0.1.0"}
+```