diff --git a/gtsam_unstable/nonlinear/tests/testBatchFixedLagSmoother.cpp b/gtsam_unstable/nonlinear/tests/testBatchFixedLagSmoother.cpp
index 20a7beff5..a4811abd8 100644
--- a/gtsam_unstable/nonlinear/tests/testBatchFixedLagSmoother.cpp
+++ b/gtsam_unstable/nonlinear/tests/testBatchFixedLagSmoother.cpp
@@ -216,7 +216,7 @@ TEST( BatchFixedLagSmoother, Example )
     Timestamps emptyNewTimestamps;
 
     size_t factorIndex = 6; // any index that does not break connectivity of the graph
-    FastVector<size_t> factorToRemove;
+    FactorIndices factorToRemove;
     factorToRemove.push_back(factorIndex);
 
     const NonlinearFactorGraph smootherFactorsBeforeRemove = smoother.getFactors();
diff --git a/gtsam_unstable/nonlinear/tests/testIncrementalFixedLagSmoother.cpp b/gtsam_unstable/nonlinear/tests/testIncrementalFixedLagSmoother.cpp
index ab6c1298a..8d99ed482 100644
--- a/gtsam_unstable/nonlinear/tests/testIncrementalFixedLagSmoother.cpp
+++ b/gtsam_unstable/nonlinear/tests/testIncrementalFixedLagSmoother.cpp
@@ -206,7 +206,7 @@ TEST( IncrementalFixedLagSmoother, Example )
 	  Timestamps emptyNewTimestamps;
 
 	  size_t factorIndex = 25; // any index that does not break connectivity of the graph
-	  FastVector<size_t> factorToRemove;
+	  FactorIndices factorToRemove;
 	  factorToRemove.push_back(factorIndex);
 
 	  const NonlinearFactorGraph smootherFactorsBeforeRemove = smoother.getFactors();