diff --git a/ortools/graph/christofides_test.cc b/ortools/graph/christofides_test.cc
index b08699ba3f..c092b06722 100644
--- a/ortools/graph/christofides_test.cc
+++ b/ortools/graph/christofides_test.cc
@@ -50,7 +50,7 @@ void ComputeAndShow(const std::string& name,
 }
 
 void TestChristofides(const std::string& name, const int size,
-                      const std::vector<int>& cost_data,
+                      absl::Span<const int> cost_data,
                       bool use_minimal_matching, bool use_mip,
                       const int expected_cost,
                       absl::string_view expected_solution) {
diff --git a/ortools/graph/hamiltonian_path_test.cc b/ortools/graph/hamiltonian_path_test.cc
index ffaa436c9f..c42a438ddf 100644
--- a/ortools/graph/hamiltonian_path_test.cc
+++ b/ortools/graph/hamiltonian_path_test.cc
@@ -339,8 +339,7 @@ void InitEuclideanCosts(int size, std::vector<double> x, std::vector<double> y,
   }
 }
 
-bool ComparePaths(const std::vector<int>& path1,
-                  const std::vector<int>& path2) {
+bool ComparePaths(absl::Span<const int> path1, absl::Span<const int> path2) {
   // Returns true if TSP paths are equal or one is the reverse of the other.
   // TSP paths always start and end with 0 (the start node). For example, paths
   // (0, 1, 2, 3, 0) and (0, 3, 2, 1, 0) are equivalent, but (0, 1, 2, 3, 0) and