diff --git a/test/gtest_factor_block_difference.cpp b/test/gtest_factor_block_difference.cpp
index 985f05da3a869bc1d4b9c122643dc41b78ec65f5..19d8d3291018ca527f92b11e05921cd4ac9c6dc1 100644
--- a/test/gtest_factor_block_difference.cpp
+++ b/test/gtest_factor_block_difference.cpp
@@ -51,7 +51,7 @@ class FixtureFactorBlockDifference : public testing::Test
             // Vector10d x_origin = problem_->stateZero().vector("POV");
             VectorComposite x_origin(problem_->stateZero().vector("POV"), "POV", {3, 4, 3});
             // Eigen::Matrix9d cov_prior = 1e-3 * Eigen::Matrix9d::Identity();
-            VectorComposite cov_prior(Vector3d(sqrt(0.1),sqrt(0.1),sqrt(0.1)), "POV", {1,1,1});
+            VectorComposite cov_prior("POV", {Vector3d(sqrt(0.1),sqrt(0.1),sqrt(0.1)),Vector3d(sqrt(0.1),sqrt(0.1),sqrt(0.1)),Vector3d(sqrt(0.1),sqrt(0.1),sqrt(0.1))});
             KF0_ = problem_->setPriorFactor(x_origin, cov_prior, t0, 0.1);
             
             //CaptureBasePtr capV0 = CaptureBase::emplace<CaptureBase>(KF0_, "Vel0", t0);