fix: update syntheses tests for theme_id requirement in generate endpoint

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

backend/tests/api_syntheses_test.rs

@@ -548,7 +548,19 @@ async fn generate_returns_202_with_job_id() {
         .create_authenticated_user("synth-gen@example.com")
         .await;
 
-    let body = serde_json::json!({});
+    // Create a theme first
+    let theme_body = serde_json::json!({
+        "name": "Test Theme",
+        "theme": "Test Topic",
+        "categories": ["Test Category"]
+    });
+    let (theme_status, theme_resp) = app
+        .post_with_session("/api/v1/themes", &theme_body, &session)
+        .await;
+    assert_eq!(theme_status.as_u16(), 201, "Theme creation should succeed");
+    let theme_id = theme_resp["id"].as_str().expect("Theme should have an id");
+
+    let body = serde_json::json!({ "theme_id": theme_id });
     let (status, resp) = app
         .post_with_session("/api/v1/syntheses/generate", &body, &session)
         .await;
@@ -582,7 +594,17 @@ async fn generate_twice_returns_error_for_second() {
         .create_authenticated_user("synth-gen-dup@example.com")
         .await;
 
-    let body = serde_json::json!({});
+    let theme_body = serde_json::json!({
+        "name": "Dup Test Theme",
+        "theme": "Dup Topic",
+        "categories": ["Cat"]
+    });
+    let (_, theme_resp) = app
+        .post_with_session("/api/v1/themes", &theme_body, &session)
+        .await;
+    let theme_id = theme_resp["id"].as_str().unwrap();
+
+    let body = serde_json::json!({ "theme_id": theme_id });
 
     // First call should succeed with 202
     let (status1, resp1) = app
@@ -624,19 +646,14 @@ async fn generate_pipeline_resolves_model_from_admin_config() {
         .create_authenticated_user("synth-model-resolve@example.com")
         .await;
 
-    // Configure user settings with provider and categories
+    // Configure user settings with provider
     let settings = serde_json::json!({
-        "theme": "Intelligence Artificielle",
-        "max_age_days": 7,
-        "categories": ["Test Category"],
-        "max_items_per_category": 4,
         "max_articles_per_source": 3,
         "max_links_per_source": 8,
 
         "use_brave_search": false,
         "article_history_days": 90,
         "batch_size": 5,
-        "summary_length": 3,
         "source_extraction_window": 3,
         "search_agent_behavior": "",
         "ai_provider": "openai",
@@ -650,6 +667,21 @@ async fn generate_pipeline_resolves_model_from_admin_config() {
         .await;
     assert_eq!(settings_status, StatusCode::OK, "Settings save should succeed");
 
+    // Create a theme with the content settings
+    let theme_body = serde_json::json!({
+        "name": "Test Theme",
+        "theme": "Intelligence Artificielle",
+        "categories": ["Test Category"],
+        "max_items_per_category": 4,
+        "max_age_days": 7,
+        "summary_length": 3
+    });
+    let (theme_status, theme_resp) = app
+        .post_with_session("/api/v1/themes", &theme_body, &session)
+        .await;
+    assert_eq!(theme_status.as_u16(), 201, "Theme creation should succeed");
+    let theme_id = theme_resp["id"].as_str().expect("Theme should have an id");
+
     // Store a fake API key — we don't need a real one, just need to get past
     // model resolution and into the LLM call
     let key_body = serde_json::json!({
@@ -664,7 +696,8 @@ async fn generate_pipeline_resolves_model_from_admin_config() {
     // Add a source so the pipeline has something to work with
     let source_body = serde_json::json!({
         "title": "Test Source",
-        "url": "https://example.com"
+        "url": "https://example.com",
+        "theme_id": theme_id
     });
     let (source_status, _) = app
         .post_with_session("/api/v1/sources", &source_body, &session)
@@ -675,7 +708,7 @@ async fn generate_pipeline_resolves_model_from_admin_config() {
     // the HTTP trigger returns 202 (not 500) and the async job doesn't crash
     // on a database error. It will fail at the LLM API call (fake key), which
     // is expected and fine — the model resolution path was exercised.
-    let gen_body = serde_json::json!({});
+    let gen_body = serde_json::json!({ "theme_id": theme_id });
     let (gen_status, gen_resp) = app
         .post_with_session("/api/v1/syntheses/generate", &gen_body, &session)
         .await;