diff --git a/tests/cpp/tree/test_quantile_hist.cc b/tests/cpp/tree/test_quantile_hist.cc
index 4959ce453775..6be71687191c 100644
--- a/tests/cpp/tree/test_quantile_hist.cc
+++ b/tests/cpp/tree/test_quantile_hist.cc
@@ -26,9 +26,8 @@ class QuantileHistMock : public QuantileHistMaker {
   struct BuilderMock : public QuantileHistMaker::Builder<GradientSumT> {
     using RealImpl = QuantileHistMaker::Builder<GradientSumT>;
 
-    BuilderMock(const TrainParam &param, std::unique_ptr<TreeUpdater> pruner,
-                DMatrix const *fmat, GenericParameter const* ctx)
-        : RealImpl(1, param, std::move(pruner), fmat, ObjInfo{ObjInfo::kRegression}, ctx) {}
+    BuilderMock(const TrainParam& param, DMatrix const* fmat, GenericParameter const* ctx)
+        : RealImpl(1, param, fmat, ObjInfo{ObjInfo::kRegression}, ctx) {}
 
    public:
     void TestInitData(const GHistIndexMatrix& gmat,
@@ -113,10 +112,10 @@ class QuantileHistMock : public QuantileHistMaker {
     dmat_ = RandomDataGenerator(kNRows, kNCols, 0.8).Seed(3).GenerateDMatrix();
     ctx_.UpdateAllowUnknown(Args{});
     if (single_precision_histogram) {
-      float_builder_.reset(new BuilderMock<float>(param_, std::move(pruner_), dmat_.get(), &ctx_));
+      float_builder_.reset(new BuilderMock<float>(param_, dmat_.get(), &ctx_));
     } else {
       double_builder_.reset(
-          new BuilderMock<double>(param_, std::move(pruner_), dmat_.get(), &ctx_));
+          new BuilderMock<double>(param_, dmat_.get(), &ctx_));
     }
   }
   ~QuantileHistMock() override = default;