diff --git a/m2cgen/assemblers/boosting.py b/m2cgen/assemblers/boosting.py
index e327b774..714da1b6 100644
--- a/m2cgen/assemblers/boosting.py
+++ b/m2cgen/assemblers/boosting.py
@@ -134,7 +134,7 @@ def _assemble_tree(self, tree):
         if "leaf" in tree:
             return ast.NumVal(tree["leaf"])
 
-        threshold = ast.NumVal(tree["split_condition"])
+        threshold = ast.NumVal(tree["split_condition"], dtype=np.float32)
         split = tree["split"]
         feature_idx = self._feature_name_to_idx.get(split, split)
         feature_ref = ast.FeatureRef(feature_idx)
diff --git a/m2cgen/ast.py b/m2cgen/ast.py
index 9b49936b..f4195af7 100644
--- a/m2cgen/ast.py
+++ b/m2cgen/ast.py
@@ -30,7 +30,9 @@ class NumExpr(Expr):
 
 
 class NumVal(NumExpr):
-    def __init__(self, value):
+    def __init__(self, value, dtype=None):
+        if dtype:
+            value = dtype(value)
         self.value = value
 
     def __str__(self):
diff --git a/tests/e2e/test_e2e.py b/tests/e2e/test_e2e.py
index b92185f8..8b6e8baa 100644
--- a/tests/e2e/test_e2e.py
+++ b/tests/e2e/test_e2e.py
@@ -35,50 +35,51 @@
 
 
 # Set of helper functions to make parametrization less verbose.
-def regression(model):
+def regression(model, test_fraction=0.02):
     return (
         model,
-        utils.get_regression_model_trainer(),
+        utils.get_regression_model_trainer(test_fraction),
         REGRESSION,
     )
 
 
-def classification(model):
+def classification(model, test_fraction=0.02):
     return (
         model,
-        utils.get_classification_model_trainer(),
+        utils.get_classification_model_trainer(test_fraction),
         CLASSIFICATION,
     )
 
 
-def classification_binary(model):
+def classification_binary(model, test_fraction=0.02):
     return (
         model,
-        utils.get_binary_classification_model_trainer(),
+        utils.get_binary_classification_model_trainer(test_fraction),
         CLASSIFICATION,
     )
 
 
-def regression_random(model):
+def regression_random(model, test_fraction=0.02):
     return (
         model,
-        utils.get_regression_random_data_model_trainer(0.01),
+        utils.get_regression_random_data_model_trainer(test_fraction),
         REGRESSION,
     )
 
 
-def classification_random(model):
+def classification_random(model, test_fraction=0.02):
     return (
         model,
-        utils.get_classification_random_data_model_trainer(0.01),
+        utils.get_classification_random_data_model_trainer(test_fraction),
         CLASSIFICATION,
     )
 
 
-def classification_binary_random(model):
+def classification_binary_random(model, test_fraction=0.02):
     return (
         model,
-        utils.get_classification_binary_random_data_model_trainer(0.01),
+        utils.get_classification_binary_random_data_model_trainer(
+            test_fraction),
         CLASSIFICATION,
     )
 
@@ -92,6 +93,8 @@ def classification_binary_random(model):
 FOREST_PARAMS = dict(n_estimators=10, random_state=RANDOM_SEED)
 XGBOOST_PARAMS = dict(base_score=0.6, n_estimators=10,
                       random_state=RANDOM_SEED)
+XGBOOST_HIST_PARAMS = dict(base_score=0.6, n_estimators=10,
+                           tree_method="hist", random_state=RANDOM_SEED)
 XGBOOST_PARAMS_LINEAR = dict(base_score=0.6, n_estimators=10,
                              feature_selector="shuffle", booster="gblinear",
                              random_state=RANDOM_SEED)
@@ -170,6 +173,14 @@ def classification_binary_random(model):
         classification(xgboost.XGBClassifier(**XGBOOST_PARAMS)),
         classification_binary(xgboost.XGBClassifier(**XGBOOST_PARAMS)),
 
+        # XGBoost (tree method "hist")
+        regression(xgboost.XGBRegressor(**XGBOOST_HIST_PARAMS),
+                   test_fraction=0.2),
+        classification(xgboost.XGBClassifier(**XGBOOST_HIST_PARAMS),
+                       test_fraction=0.2),
+        classification_binary(xgboost.XGBClassifier(**XGBOOST_HIST_PARAMS),
+                              test_fraction=0.2),
+
         # XGBoost (LINEAR)
         regression(xgboost.XGBRegressor(**XGBOOST_PARAMS_LINEAR)),
         classification(xgboost.XGBClassifier(**XGBOOST_PARAMS_LINEAR)),
diff --git a/tests/test_ast.py b/tests/test_ast.py
index 36b9421a..32c4b4f4 100644
--- a/tests/test_ast.py
+++ b/tests/test_ast.py
@@ -1,3 +1,4 @@
+import numpy as np
 from m2cgen import ast
 
 
@@ -69,3 +70,9 @@ def test_count_all_exprs_types():
         ast.BinNumOpType.MUL)
 
     assert ast.count_exprs(expr) == 27
+
+
+def test_num_val():
+    assert type(ast.NumVal(1).value) == int
+    assert type(ast.NumVal(1, dtype=np.float32).value) == np.float32
+    assert type(ast.NumVal(1, dtype=np.float64).value) == np.float64