fix: embed_batch length+index pairing; reject non-numeric components

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

tests/embed_tests.rs

@@ -1,4 +1,5 @@
-use alpha_id::embed::{EmbeddingStore, estimate};
+use alpha_id::embed::{EmbeddingStore, embed_batch, estimate};
+use alpha_id::ionos::IonosClient;
 
 #[test]
 fn cache_key_is_stable_sha256() {
@@ -26,3 +27,103 @@ fn estimate_reports_pending_count_and_chars() {
     assert_eq!(est.items, 2);
     assert_eq!(est.chars, 5);
 }
+
+// ---------------------------------------------------------------------------
+// Regression tests for embed_batch hardening (Fix 1 & Fix 2)
+// ---------------------------------------------------------------------------
+
+/// Spin up a tiny_http mock server that serves one fixed JSON response, then
+/// return an IonosClient pointed at it together with a temp token file.
+fn make_mock_client(
+    response_body: &str,
+    token_dir: &tempfile::TempDir,
+) -> (IonosClient, std::net::SocketAddr, std::thread::JoinHandle<()>) {
+    use tiny_http::{Server, Response};
+
+    let server = Server::http("127.0.0.1:0").unwrap();
+    let addr = server.server_addr().to_ip().unwrap();
+
+    // Write a dummy token file
+    let token_path = token_dir.path().join("token.txt");
+    std::fs::write(&token_path, "dummy-token").unwrap();
+
+    let body = response_body.to_string();
+    let handle = std::thread::spawn(move || {
+        if let Ok(req) = server.recv() {
+            let response = Response::from_string(body)
+                .with_header(
+                    "Content-Type: application/json".parse::<tiny_http::Header>().unwrap(),
+                );
+            let _ = req.respond(response);
+        }
+    });
+
+    let base_url = format!("http://{}", addr);
+    let client = IonosClient::new(&base_url, token_path.to_str().unwrap()).unwrap();
+    (client, addr, handle)
+}
+
+#[test]
+fn embed_batch_happy_path_index_pairing() {
+    let token_dir = tempfile::tempdir().unwrap();
+    let embed_dir = tempfile::tempdir().unwrap();
+
+    let body = r#"{"data":[{"index":0,"embedding":[0.1,0.2]},{"index":1,"embedding":[0.3,0.4]}]}"#;
+    let (client, _addr, handle) = make_mock_client(body, &token_dir);
+
+    let store = EmbeddingStore::open(embed_dir.path().to_str().unwrap(), "test-model").unwrap();
+    let texts = vec!["a".to_string(), "b".to_string()];
+
+    let result = embed_batch(&client, &store, "test-model", &texts);
+    handle.join().unwrap();
+
+    assert_eq!(result.unwrap(), 2, "should return count of stored vectors");
+
+    let va = store.get("a").expect("vector for 'a' must be cached");
+    let vb = store.get("b").expect("vector for 'b' must be cached");
+    assert_eq!(va, vec![0.1_f32, 0.2_f32], "vector for 'a' mismatch");
+    assert_eq!(vb, vec![0.3_f32, 0.4_f32], "vector for 'b' mismatch");
+}
+
+#[test]
+fn embed_batch_length_mismatch_is_err_no_partial_write() {
+    let token_dir = tempfile::tempdir().unwrap();
+    let embed_dir = tempfile::tempdir().unwrap();
+
+    // API returns only 1 item for 2 texts
+    let body = r#"{"data":[{"index":0,"embedding":[0.1,0.2]}]}"#;
+    let (client, _addr, handle) = make_mock_client(body, &token_dir);
+
+    let store = EmbeddingStore::open(embed_dir.path().to_str().unwrap(), "test-model").unwrap();
+    let texts = vec!["a".to_string(), "b".to_string()];
+
+    let result = embed_batch(&client, &store, "test-model", &texts);
+    handle.join().unwrap();
+
+    assert!(result.is_err(), "length mismatch must be an Err, not Ok");
+    assert!(store.get("b").is_none(), "partial write for 'b' must not occur");
+}
+
+#[test]
+fn embed_batch_reordered_index_maps_to_correct_text() {
+    let token_dir = tempfile::tempdir().unwrap();
+    let embed_dir = tempfile::tempdir().unwrap();
+
+    // API returns items in reverse index order (index 1 first, index 0 second)
+    let body = r#"{"data":[{"index":1,"embedding":[0.3,0.4]},{"index":0,"embedding":[0.1,0.2]}]}"#;
+    let (client, _addr, handle) = make_mock_client(body, &token_dir);
+
+    let store = EmbeddingStore::open(embed_dir.path().to_str().unwrap(), "test-model").unwrap();
+    let texts = vec!["a".to_string(), "b".to_string()];
+
+    let result = embed_batch(&client, &store, "test-model", &texts);
+    handle.join().unwrap();
+
+    assert_eq!(result.unwrap(), 2, "should return count of stored vectors");
+
+    let va = store.get("a").expect("vector for 'a' must be cached");
+    let vb = store.get("b").expect("vector for 'b' must be cached");
+    // index 0 → texts[0] = "a" → [0.1, 0.2]; index 1 → texts[1] = "b" → [0.3, 0.4]
+    assert_eq!(va, vec![0.1_f32, 0.2_f32], "reordered index: vector for 'a' mismatch");
+    assert_eq!(vb, vec![0.3_f32, 0.4_f32], "reordered index: vector for 'b' mismatch");
+}