Update error responses

1 files changed, 110 insertions, 5 deletions

diff --git a/src/tests.rs b/src/tests.rs
index 586f35a..5b21352 100644
--- a/src/tests.rs
+++ b/src/tests.rs
@@ -116,7 +116,10 @@ async fn create_returns_the_measurement_and_location(pool: PgPool) {
 async fn create_rejects_bad_bodies(pool: PgPool) {
     let app = router(pool);
     let cases = [
-        (json!({"metric_type": "Hip"}).to_string(), StatusCode::UNPROCESSABLE_ENTITY),
+        (
+            json!({"metric_type": "Hip"}).to_string(),
+            StatusCode::UNPROCESSABLE_ENTITY,
+        ),
         (
             measurement("2026-10-14T12:00:00Z", "Nope", 1.0, "Kilogram"),
             StatusCode::UNPROCESSABLE_ENTITY,
@@ -219,8 +222,14 @@ async fn list_ranges_are_inclusive_of_both_days(pool: PgPool) {
     let cases = [
         ("/measurements?from=2026-10-15", vec![2.0, 3.0, 4.0]),
         ("/measurements?to=2026-10-14", vec![1.0]),
-        ("/measurements?from=2026-10-14&to=2026-10-15", vec![1.0, 2.0, 3.0]),
-        ("/measurements?from=2026-10-15&to=2026-10-15", vec![2.0, 3.0]),
+        (
+            "/measurements?from=2026-10-14&to=2026-10-15",
+            vec![1.0, 2.0, 3.0],
+        ),
+        (
+            "/measurements?from=2026-10-15&to=2026-10-15",
+            vec![2.0, 3.0],
+        ),
         ("/measurements?from=2030-01-01", vec![]),
     ];
     for (uri, expected) in cases {
@@ -236,7 +245,10 @@ async fn list_combines_filters_with_order_and_limit(pool: PgPool) {
     seed(&app).await;
     let cases = [
         ("/measurements?from=2026-10-15&limit=1", vec![2.0]),
-        ("/measurements?from=2026-10-15&order=desc&limit=2", vec![4.0, 3.0]),
+        (
+            "/measurements?from=2026-10-15&order=desc&limit=2",
+            vec![4.0, 3.0],
+        ),
         ("/measurements?date=2026-10-15&order=desc", vec![3.0, 2.0]),
     ];
     for (uri, expected) in cases {
@@ -350,8 +362,101 @@ async fn delete_is_idempotent(pool: PgPool) {
 #[sqlx::test]
 async fn old_paths_are_gone(pool: PgPool) {
     let app = router(pool);
-    for uri in ["/", "/all", "/search?from=2026-10-14", "/units", "/metric_types"] {
+    for uri in [
+        "/",
+        "/all",
+        "/search?from=2026-10-14",
+        "/units",
+        "/metric_types",
+    ] {
         let (status, _) = get_json(&app, uri).await;
         assert_eq!(status, StatusCode::NOT_FOUND, "{uri}");
     }
 }
+
+#[sqlx::test]
+async fn errors_have_a_json_body(pool: PgPool) {
+    let app = router(pool);
+    let missing = format!("/measurements/{}", Uuid::now_v7());
+    let valid = measurement("2026-10-14T12:00:00Z", "Waist", 80.0, "Centimeter");
+    let invalid_pair = measurement("2026-10-14T12:00:00Z", "Waist", 80.0, "Kilogram");
+    let cases = [
+        (
+            Method::GET,
+            "/measurements?limit=0".to_owned(),
+            None,
+            StatusCode::BAD_REQUEST,
+        ),
+        (
+            Method::GET,
+            "/measurements?order=sideways".to_owned(),
+            None,
+            StatusCode::BAD_REQUEST,
+        ),
+        (
+            Method::GET,
+            "/measurements?date=bad".to_owned(),
+            None,
+            StatusCode::BAD_REQUEST,
+        ),
+        (
+            Method::GET,
+            "/measurements/not-a-uuid".to_owned(),
+            None,
+            StatusCode::BAD_REQUEST,
+        ),
+        (Method::GET, missing.clone(), None, StatusCode::NOT_FOUND),
+        (Method::PUT, missing, Some(valid), StatusCode::NOT_FOUND),
+        (
+            Method::POST,
+            "/measurements".to_owned(),
+            Some("not json".to_owned()),
+            StatusCode::BAD_REQUEST,
+        ),
+        (
+            Method::POST,
+            "/measurements".to_owned(),
+            Some(invalid_pair),
+            StatusCode::UNPROCESSABLE_ENTITY,
+        ),
+        (Method::GET, "/nope".to_owned(), None, StatusCode::NOT_FOUND),
+        (
+            Method::PATCH,
+            "/measurements".to_owned(),
+            None,
+            StatusCode::METHOD_NOT_ALLOWED,
+        ),
+    ];
+    for (method, uri, body, expected) in cases {
+        let (status, _, body) = send(&app, method.clone(), &uri, body).await;
+        assert_eq!(status, expected, "{method} {uri}");
+        assert!(body["error"].is_string(), "{method} {uri}: {body}");
+    }
+}
+
+#[sqlx::test]
+async fn error_messages_explain_the_problem(pool: PgPool) {
+    let app = router(pool);
+    let cases = [
+        ("/measurements?limit=0", "limit must be positive"),
+        (
+            "/measurements?date=2026-10-15&from=2026-10-14",
+            "date can't be combined with from or to",
+        ),
+        (
+            "/measurements?from=2026-10-16&to=2026-10-14",
+            "from must not be after to",
+        ),
+    ];
+    for (uri, message) in cases {
+        let (_, body) = get_json(&app, uri).await;
+        assert_eq!(body["error"], message, "{uri}");
+    }
+    let body = measurement("2026-10-14T12:00:00Z", "Waist", 80.0, "Kilogram");
+    let (_, _, body) = send(&app, Method::POST, "/measurements", Some(body)).await;
+    let message = body["error"].as_str().unwrap();
+    assert!(
+        message.contains("Invalid pair Waist, Kilogram"),
+        "{message}"
+    );
+}