fix: harden single-machine load handling

server/im_http_test.go

@@ -158,6 +158,7 @@ type testRelationsStore struct {
 	deleteTenant   types.TenantID
 	deleteUser     types.Uid
 	deletePeer     types.Uid
+	resolveNil     bool
 }
 
 type testFavoritesStore struct {
@@ -962,6 +963,9 @@ func (s *testRelationsStore) CountPendingFriendRequests(tenantID types.TenantID,
 }
 
 func (s *testRelationsStore) ResolveFriendRequest(_ types.TenantID, requestID string, actor types.Uid, status string, handledAt time.Time) (*types.FriendRequest, error) {
+	if s.resolveNil {
+		return nil, nil
+	}
 	return &types.FriendRequest{
 		TenantID:    7,
 		RequestID:   requestID,
@@ -975,6 +979,28 @@ func (s *testRelationsStore) ResolveFriendRequest(_ types.TenantID, requestID st
 	}, nil
 }
 
+func TestServeIMFriendRequestActionRejectsEmptyStoreResult(t *testing.T) {
+	ctrl := gomock.NewController(t)
+	defer ctrl.Finish()
+	expectIMBearer(t, ctrl, "token-1", 7, 42)
+
+	oldRelations := store.Relations
+	store.Relations = &testRelationsStore{resolveNil: true}
+	t.Cleanup(func() { store.Relations = oldRelations })
+
+	req := httptest.NewRequest(http.MethodPost, "/v1/im/friend-requests/frq-1/accept", nil)
+	req.Header.Set("Authorization", "Bearer token-1")
+	rec := httptest.NewRecorder()
+	serveIMFriendRequestAction(rec, req)
+
+	if rec.Code != http.StatusInternalServerError {
+		t.Fatalf("status: got %d, want %d; body=%s", rec.Code, http.StatusInternalServerError, rec.Body.String())
+	}
+	if response := decodeIMHTTPResponse(t, rec); response.Reason != imReasonInternal {
+		t.Fatalf("reason: got %q, want %q", response.Reason, imReasonInternal)
+	}
+}
+
 func (s *testRelationsStore) ListFriends(_ types.TenantID, _ types.Uid, _, _, _ string, _ int) ([]types.FriendListItem, string, error) {
 	return s.friends, "", nil
 }