fix: cover api edge cases

src/clients/funtranslations.rs

@@ -1,4 +1,4 @@
-use crate::{domain::TranslationKind, error::AppError};
+use crate::{clients::body, domain::TranslationKind, error::AppError};
 use serde::Deserialize;
 use std::time::Duration;
 use tracing::instrument;
@@ -40,11 +40,14 @@ impl TranslationClient {
             )));
         }
 
-        response
-            .json::<TranslationResponse>()
-            .await
-            .map(|payload| payload.contents.translated)
-            .map_err(|error| map_reqwest_error(&error))
+        let payload = body::read_json::<TranslationResponse>(response, "FunTranslations").await?;
+        if payload.contents.translated.trim().is_empty() {
+            Err(AppError::InvalidUpstreamData(
+                "FunTranslations returned an empty translation".to_owned(),
+            ))
+        } else {
+            Ok(payload.contents.translated)
+        }
     }
 }
 
@@ -112,6 +115,26 @@ mod tests {
         assert_eq!(translated, "Created, it was.");
     }
 
+    #[tokio::test]
+    async fn rejects_empty_translations_so_callers_can_fallback() {
+        let server = MockServer::start().await;
+        Mock::given(matchers::method("POST"))
+            .and(matchers::path("/translate/yoda.json"))
+            .respond_with(ResponseTemplate::new(200).set_body_json(serde_json::json!({
+                "contents": { "translated": "   " }
+            })))
+            .mount(&server)
+            .await;
+        let client = client_for(&server);
+
+        let error = client
+            .translate(TranslationKind::Yoda, "hello")
+            .await
+            .expect_err("empty translation should fail");
+
+        assert!(error.to_string().contains("empty translation"));
+    }
+
     #[tokio::test]
     async fn maps_translation_http_failures_to_upstream_errors() {
         let server = MockServer::start().await;