test(rest): pin /v1/node-connections empty-list contract

Both the list and per-pair endpoints must answer 200 with `[]`.
golinstor's reconciler treats anything else (404, error envelope) as
a hard failure; the empty body is the canonical "no inter-satellite
tunnels here" answer.

Co-Authored-By: Claude <noreply@anthropic.com>
Signed-off-by: Andrei Kvapil <kvapss@gmail.com>

Author: kvaps

pkg/rest/node_connections_test.go

@@ -0,0 +1,64 @@
+/*
+Copyright 2026 Cozystack contributors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package rest
+
+import (
+	"encoding/json"
+	"net/http"
+	"testing"
+
+	"github.com/cozystack/blockstor/pkg/store"
+)
+
+// TestNodeConnectionsReturnEmpty pins the contract: list and per-pair
+// node-connections both 200 with `[]`. golinstor's polling loop logs an
+// error for any non-200, so the empty-but-present shape is what keeps
+// the controller log clean for cozystack's flat-L2 setup where there
+// are no inter-satellite tunnels to report.
+func TestNodeConnectionsReturnEmpty(t *testing.T) {
+	base, stop := startServerWithStore(t, store.NewInMemory())
+	defer stop()
+
+	for _, path := range []string{
+		"/v1/node-connections",
+		"/v1/node-connections/n1/n2",
+	} {
+		resp := httpGet(t, base+path)
+
+		if resp.StatusCode != http.StatusOK {
+			_ = resp.Body.Close()
+			t.Errorf("%s status: got %d, want 200", path, resp.StatusCode)
+
+			continue
+		}
+
+		var got []map[string]any
+
+		err := json.NewDecoder(resp.Body).Decode(&got)
+		_ = resp.Body.Close()
+
+		if err != nil {
+			t.Errorf("%s decode: %v", path, err)
+
+			continue
+		}
+
+		if len(got) != 0 {
+			t.Errorf("%s body: got %d entries, want 0", path, len(got))
+		}
+	}
+}