diff --git a/test/gtest_factor_diff_drive.cpp b/test/gtest_factor_diff_drive.cpp
index 8e97b7f177ef034f94e18c881c94630fcff96668..39f0af8be47f69bb928cc06e3e0318b1759f2435 100644
--- a/test/gtest_factor_diff_drive.cpp
+++ b/test/gtest_factor_diff_drive.cpp
@@ -444,10 +444,10 @@ TEST(FactorDiffDrive, preintegrate_and_solve_sensor_intrinsics_gt)
     Vector3d x1(1.5, -1.5, -M_PI/2.0);
     Vector3d x2(3.0, -3.0, 0.0);
     // Matrix3d P0; P0.setIdentity();
-    VectorComposite P0(Vector3d(0,0,0), "PO", {2,1});
+    VectorComposite s0(Vector3d(0,0,0), "PO", {2,1});
 
     // set prior at t=0 and processor origin
-    auto F0 = problem->setPriorFactor(x0, P0, t, 0.1);
+    auto F0 = problem->setPriorFactor(x0, s0, t, 0.1);
     processor->setOrigin(F0);
 
     // right turn 90 deg in N steps --> ends up in (1.5, -1.5, -pi/2)
@@ -578,10 +578,10 @@ TEST(FactorDiffDrive, preintegrate_and_solve_sensor_intrinsics)
     Vector3d x1(1.5, -1.5, -M_PI/2.0);
     Vector3d x2(3.0, -3.0, 0.0);
     // Matrix3d P0; P0.setIdentity();
-    VectorComposite P0(Vector3d(1,1,1), "PO", {2,1});
+    VectorComposite s0(Vector3d(1,1,1), "PO", {2,1});
 
     // set prior at t=0 and processor origin
-    auto F0 = problem->setPriorFactor(x0, P0, t, 0.1);
+    auto F0 = problem->setPriorFactor(x0, s0, t, 0.1);
     processor->setOrigin(F0);
 
     // right turn 90 deg in N steps --> ends up in (1.5, -1.5, -pi/2)
diff --git a/test/gtest_odom_2d.cpp b/test/gtest_odom_2d.cpp
index b4c3e267bb5f408c2b54252dfe999c26e4246f21..8d97fc8d063ed1a08c36b25f259353cc74852f76 100644
--- a/test/gtest_odom_2d.cpp
+++ b/test/gtest_odom_2d.cpp
@@ -120,7 +120,7 @@ TEST(Odom2d, FactorFix_and_FactorOdom2d)
     TimeStamp t0(0.0),  t = t0;
     double              dt = .01;
     VectorComposite x0(Vector3d(0,0,0), "PO", {2,1});
-    VectorComposite P0(Vector3d(sqrt(0.1),sqrt(0.1),sqrt(0.1)), "PO", {2,1});
+    VectorComposite s0(Vector3d(sqrt(0.1),sqrt(0.1),sqrt(0.1)), "PO", {2,1});
     Vector3d            delta (2,0,0);
     Matrix3d delta_cov; delta_cov << .02, 0, 0, 0, .025, .02, 0, .02, .02;
 
@@ -128,7 +128,7 @@ TEST(Odom2d, FactorFix_and_FactorOdom2d)
     CeresManager        ceres_manager(Pr);
 
     // KF0 and absolute prior
-    FrameBasePtr        F0 = Pr->setPriorFactor(x0, P0,t0, dt/2);
+    FrameBasePtr        F0 = Pr->setPriorFactor(x0, s0,t0, dt/2);
 
     // KF1 and motion from KF0
     t += dt;
@@ -171,8 +171,8 @@ TEST(Odom2d, FactorFix_and_FactorOdom2d)
     ASSERT_TRUE(Pr->getFrameCovariance(F2, P2_solver));
 
     ASSERT_POSE2d_APPROX(F0->getStateVector(), Vector3d(0,0,0), 1e-6);
-    auto P0_vector = P0.vector("PO");
-    ASSERT_MATRIX_APPROX(P0_solver, MatrixXd((P0_vector.array() * P0_vector.array()).matrix().asDiagonal()), 1e-6);
+    auto s0_vector = s0.vector("PO");
+    ASSERT_MATRIX_APPROX(P0_solver, MatrixXd((s0_vector.array() * s0_vector.array()).matrix().asDiagonal()), 1e-6);
     ASSERT_POSE2d_APPROX(F1->getStateVector(), Vector3d(2,0,0), 1e-6);
     ASSERT_MATRIX_APPROX(P1_solver, P1, 1e-6);
     ASSERT_POSE2d_APPROX(F2->getStateVector(), Vector3d(4,0,0), 1e-6);
@@ -191,7 +191,7 @@ TEST(Odom2d, VoteForKfAndSolve)
     // Vector3d x0(0,0,0);
     VectorComposite x0(Vector3d(0,0,0), "PO", {2,1});
     // Eigen::Matrix3d P0 = Eigen::Matrix3d::Identity() * 0.1;
-    VectorComposite P0(Vector3d(sqrt(0.1),sqrt(0.1),sqrt(0.1)), "PO", {2,1});
+    VectorComposite s0(Vector3d(sqrt(0.1),sqrt(0.1),sqrt(0.1)), "PO", {2,1});
     // motion data
     VectorXd data(Vector2d(1, M_PI_4) ); // advance 1m turn pi/4 rad (45 deg). Need 8 steps for a complete turn
     Eigen::MatrixXd data_cov = Eigen::MatrixXd::Identity(2, 2) * 0.01;
@@ -221,7 +221,7 @@ TEST(Odom2d, VoteForKfAndSolve)
     CeresManager ceres_manager(problem);
 
     // Origin Key Frame
-    auto KF = problem->setPriorFactor(x0, P0, t, dt/2);
+    auto KF = problem->setPriorFactor(x0, s0, t, dt/2);
     processor_odom2d->setOrigin(KF);
 
     ceres_manager.solve(SolverManager::ReportVerbosity::BRIEF);
diff --git a/test/gtest_processor_motion.cpp b/test/gtest_processor_motion.cpp
index 7704bd572763577eb2bf8185e2dd3c602fd2c04c..509f495c1bd4c56be08f2d70279e6fba9a5b6ccc 100644
--- a/test/gtest_processor_motion.cpp
+++ b/test/gtest_processor_motion.cpp
@@ -109,8 +109,8 @@ TEST_F(ProcessorMotion_test, IntegrateStraightFactorPrior)
     // Vector3d x0; x0 << 0, 0, 0;
     VectorComposite x0(Vector3d(0,0,0), "PO", {2,1});
     // Matrix3d P0; P0.setIdentity();
-    VectorComposite P0(Vector3d(1,1,1), "PO", {2,1});
-    auto KF_0 = problem->setPriorFactor(x0, P0, t, 0.01);
+    VectorComposite s0(Vector3d(1,1,1), "PO", {2,1});
+    auto KF_0 = problem->setPriorFactor(x0, s0, t, 0.01);
     processor->setOrigin(KF_0);
 
     data << 1, 0; // advance straight
@@ -136,7 +136,7 @@ TEST_F(ProcessorMotion_test, IntegrateStraightFixPrior)
     // Vector3d x0; x0 << 0, 0, 0;
     // Matrix3d P0; P0.setIdentity();
     VectorComposite x0(Vector3d(0,0,0), "PO", {2,1});
-    VectorComposite P0(Vector3d(1,1,1), "PO", {2,1});
+    VectorComposite s0(Vector3d(1,1,1), "PO", {2,1});
     auto KF_0 = problem->setPriorFix(x0, t, 0.01);
     processor->setOrigin(KF_0);
 
@@ -186,8 +186,8 @@ TEST_F(ProcessorMotion_test, IntegrateCircleFactorPrior)
     // Vector3d x0; x0 << 0, 0, 0;
     VectorComposite x0(Vector3d(0,0,0), "PO", {2,1});
     // Matrix3d P0; P0.setIdentity();
-    VectorComposite P0(Vector3d(1,1,1), "PO", {2,1});
-    auto KF_0 = problem->setPriorFactor(x0, P0, t, 0.01);
+    VectorComposite s0(Vector3d(1,1,1), "PO", {2,1});
+    auto KF_0 = problem->setPriorFactor(x0, s0, t, 0.01);
     processor->setOrigin(KF_0);
 
     data << 1, 2*M_PI/10; // advance in circle
@@ -213,7 +213,7 @@ TEST_F(ProcessorMotion_test, IntegrateCircleFixPrior)
     // Vector3d x0; x0 << 0, 0, 0;
     // Matrix3d P0; P0.setIdentity();
     VectorComposite x0(Vector3d(0,0,0), "PO", {2,1});
-    VectorComposite P0(Vector3d(1,1,1), "PO", {2,1});
+    VectorComposite s0(Vector3d(1,1,1), "PO", {2,1});
     auto KF_0 = problem->setPriorFix(x0, t, 0.01);
     processor->setOrigin(KF_0);
 
@@ -281,8 +281,8 @@ TEST_F(ProcessorMotion_test, splitBufferFactorPrior)
     // Vector3d x0; x0 << 0, 0, 0;
     VectorComposite x0(Vector3d(0,0,0), "PO", {2,1});
     // Matrix3d P0; P0.setIdentity();
-    VectorComposite P0(Vector3d(1,1,1), "PO", {2,1});
-    auto KF_0 = problem->setPriorFactor(x0, P0, t, 0.01);
+    VectorComposite s0(Vector3d(1,1,1), "PO", {2,1});
+    auto KF_0 = problem->setPriorFactor(x0, s0, t, 0.01);
     processor->setOrigin(KF_0);
 
     data << 1, 2*M_PI/10; // advance in circle
@@ -326,7 +326,7 @@ TEST_F(ProcessorMotion_test, splitBufferFixPrior)
     // Vector3d x0; x0 << 0, 0, 0;
     // Matrix3d P0; P0.setIdentity();
     VectorComposite x0(Vector3d(0,0,0), "PO", {2,1});
-    VectorComposite P0(Vector3d(1,1,1), "PO", {2,1});
+    VectorComposite s0(Vector3d(1,1,1), "PO", {2,1});
     auto KF_0 = problem->setPriorFix(x0, t, 0.01);
     processor->setOrigin(KF_0);