Add basic test

api.go

@@ -1600,7 +1600,7 @@ func importExistenceColumns(qcx *Qcx, index *Index, columnIDs []uint64) error {
 // ShardDistribution returns an object representing the distribution of shards
 // across nodes for each index, distinguishing between primary and replica.
 // The structure of this information is [indexName][nodeID][primaryOrReplica]uint64.
-// This function supports a view in the UI, and
+// This function supports a view in the UI.
 func (api *API) ShardDistribution(ctx context.Context) map[string]interface{} {
 	distByIndex := make(map[string]interface{})
 	maxShards := api.MaxShards(ctx)

server/handler_test.go

@@ -400,6 +400,32 @@ func TestHandler_Endpoints(t *testing.T) {
 		}
 	})
 
+	t.Run("UI/shard-distribution", func(t *testing.T) {
+		// This tests the response structure, not the shard distribution.
+		w := httptest.NewRecorder()
+		h.ServeHTTP(w, test.MustNewHTTPRequest("GET", "/ui/shard-distribution", nil))
+		if w.Code != gohttp.StatusOK {
+			t.Fatalf("unexpected status code: %d", w.Code)
+		}
+
+		ret := mustJSONDecode(t, w.Body)
+
+		for indexName := range ret {
+			indexData := ret[indexName].(map[string]interface{})
+			for nodeName := range indexData {
+				nodeData := indexData[nodeName].(map[string]interface{})
+				_, hasPrimary := nodeData["primary-shards"]
+				_, hasReplica := nodeData["replica-shards"]
+
+				responseOK := hasPrimary && hasReplica
+				if !responseOK {
+					t.Fatalf("unexpected response structure")
+				}
+			}
+
+		}
+	})
+
 	t.Run("Metrics", func(t *testing.T) {
 		w := httptest.NewRecorder()
 		h.ServeHTTP(w, test.MustNewHTTPRequest("GET", "/metrics", nil))