diff --git a/gtsam/linear/tests/testGaussianBayesNet.cpp b/gtsam/linear/tests/testGaussianBayesNet.cpp
index 488368c72..eafefb3cb 100644
--- a/gtsam/linear/tests/testGaussianBayesNet.cpp
+++ b/gtsam/linear/tests/testGaussianBayesNet.cpp
@@ -137,7 +137,7 @@ TEST( GaussianBayesNet, optimize3 )
 }
 
 /* ************************************************************************* */
-TEST(GaussianBayesNet, ordering) 
+TEST(GaussianBayesNet, ordering)
 {
   Ordering expected;
   expected += _x_, _y_;
@@ -155,7 +155,7 @@ TEST( GaussianBayesNet, MatrixStress )
   bn.emplace_shared<GC>(_z_, Vector2(5, 6), 6 * I_2x2);
 
   const VectorValues expected = bn.optimize();
-  for (const auto keys :
+  for (const auto& keys :
        {KeyVector({_x_, _y_, _z_}), KeyVector({_x_, _z_, _y_}),
         KeyVector({_y_, _x_, _z_}), KeyVector({_y_, _z_, _x_}),
         KeyVector({_z_, _x_, _y_}), KeyVector({_z_, _y_, _x_})}) {
@@ -183,7 +183,7 @@ TEST( GaussianBayesNet, backSubstituteTranspose )
 
   VectorValues actual = smallBayesNet.backSubstituteTranspose(x);
   EXPECT(assert_equal(expected, actual));
-  
+
   const auto ordering = noisyBayesNet.ordering();
   const Matrix R = smallBayesNet.matrix(ordering).first;
   const Vector expected_vector = R.transpose().inverse() * x.vector(ordering);
@@ -206,7 +206,7 @@ TEST( GaussianBayesNet, backSubstituteTransposeNoisy )
 
   VectorValues actual = noisyBayesNet.backSubstituteTranspose(x);
   EXPECT(assert_equal(expected, actual));
-  
+
   const auto ordering = noisyBayesNet.ordering();
   const Matrix R = noisyBayesNet.matrix(ordering).first;
   const Vector expected_vector = R.transpose().inverse() * x.vector(ordering);
diff --git a/gtsam_unstable/geometry/tests/testSimilarity3.cpp b/gtsam_unstable/geometry/tests/testSimilarity3.cpp
index b07b5acd6..d23346896 100644
--- a/gtsam_unstable/geometry/tests/testSimilarity3.cpp
+++ b/gtsam_unstable/geometry/tests/testSimilarity3.cpp
@@ -244,7 +244,7 @@ TEST(Similarity3, GroupAction) {
       &Similarity3::transformFrom, _1, _2, boost::none, boost::none);
 
   Point3 q(1, 2, 3);
-  for (const auto T : { T1, T2, T3, T4, T5, T6 }) {
+  for (const auto& T : { T1, T2, T3, T4, T5, T6 }) {
     Point3 q(1, 0, 0);
     Matrix H1 = numericalDerivative21<Point3, Similarity3, Point3>(f, T, q);
     Matrix H2 = numericalDerivative22<Point3, Similarity3, Point3>(f, T, q);