diff --git a/cfmtoolbox/models.py b/cfmtoolbox/models.py
index edb095e..6baaa10 100644
--- a/cfmtoolbox/models.py
+++ b/cfmtoolbox/models.py
@@ -64,16 +64,21 @@ def __str__(self) -> str:
 
 @dataclass
 class CFM:
-    features: list[Feature]
+    root: Feature
     require_constraints: list[Constraint]
     exclude_constraints: list[Constraint]
 
-    def add_feature(self, feature: Feature):
-        if feature not in self.features:
-            self.features.append(feature)
+    @property
+    def features(self) -> list[Feature]:
+        features = [self.root]
+
+        for feature in features:
+            features.extend(feature.children)
+
+        return features
 
     def is_unbound(self) -> bool:
-        return self.features[0].is_unbound()
+        return self.root.is_unbound()
 
 
 @dataclass
@@ -83,11 +88,10 @@ class FeatureNode:
 
     def validate(self, cfm: CFM) -> bool:
         # Check if root feature is valid
-        root_feature = cfm.features[0]
-        if root_feature.name != self.value.split("#")[0]:
+        if cfm.root.name != self.value.split("#")[0]:
             return False
 
-        if not self.validate_children(root_feature):
+        if not self.validate_children(cfm.root):
             return False
 
         return self.validate_constraints(cfm)
diff --git a/cfmtoolbox/plugins/big_m.py b/cfmtoolbox/plugins/big_m.py
index 5fa45a9..48bbdb2 100644
--- a/cfmtoolbox/plugins/big_m.py
+++ b/cfmtoolbox/plugins/big_m.py
@@ -8,25 +8,24 @@ def apply_big_m(model: CFM | None) -> CFM | None:
         print("No model loaded.")
         return None
 
-    global_upper_bound = get_global_upper_bound(model.features[0])
+    global_upper_bound = get_global_upper_bound(model.root)
 
-    replace_infinite_upper_bound_with_global_upper_bound(
-        model.features[0], global_upper_bound
-    )
+    replace_infinite_upper_bound_with_global_upper_bound(model.root, global_upper_bound)
 
     print("Successfully applied Big-M global bound.")
 
     return model
 
 
-def get_global_upper_bound(feature: Feature):
+def get_global_upper_bound(feature: Feature) -> int:
     global_upper_bound = feature.instance_cardinality.intervals[-1].upper
-    local_upper_bound = global_upper_bound
 
     # Terminate calculation if the upper bound is infinite
-    if local_upper_bound is None:
+    if global_upper_bound is None:
         return 0
 
+    local_upper_bound = global_upper_bound
+
     # Recursively calculate the global upper bound by multiplying the upper bounds of all paths
     # from the root feature excluding paths that contain a feature with an infinite upper bound
     for child in feature.children:
diff --git a/cfmtoolbox/plugins/featureide_import.py b/cfmtoolbox/plugins/featureide_import.py
index ce9ed0f..47ac9b1 100644
--- a/cfmtoolbox/plugins/featureide_import.py
+++ b/cfmtoolbox/plugins/featureide_import.py
@@ -85,7 +85,7 @@ def parse_feature(feature_element: Element, parent: Feature | None) -> Feature:
     return feature
 
 
-def parse_root(root_element: Element) -> list[Feature]:
+def parse_root(root_element: Element) -> tuple[Feature, list[Feature]]:
     root = parse_feature(root_element, parent=None)
 
     features = [root]
@@ -93,7 +93,7 @@ def parse_root(root_element: Element) -> list[Feature]:
     for feature in features:
         features.extend(feature.children)
 
-    return features
+    return root, features
 
 
 def parse_formula_value_and_feature(
@@ -173,17 +173,17 @@ def parse_constraints(
     return (require_constraints, exclude_constraints, eliminated_constraints)
 
 
-def parse_cfm(root: Element) -> CFM:
-    struct = root.find("struct")
+def parse_cfm(root_element: Element) -> CFM:
+    struct = root_element.find("struct")
 
     if struct is None:
         raise TypeError("No valid Feature structure found in XML file")
 
     root_struct = struct[0]
-    features = parse_root(root_struct)
+    root_feature, all_features = parse_root(root_struct)
 
     require_constraints, exclude_constraints, eliminated_constraints = (
-        parse_constraints(root.find("constraints"), features)
+        parse_constraints(root_element.find("constraints"), all_features)
     )
 
     formatted_eliminated_constraints = [
@@ -198,7 +198,7 @@ def parse_cfm(root: Element) -> CFM:
             file=sys.stderr,
         )
 
-    return CFM(features, require_constraints, exclude_constraints)
+    return CFM(root_feature, require_constraints, exclude_constraints)
 
 
 @app.importer(".xml")
diff --git a/cfmtoolbox/plugins/json_export.py b/cfmtoolbox/plugins/json_export.py
index 2db149b..63c7f75 100644
--- a/cfmtoolbox/plugins/json_export.py
+++ b/cfmtoolbox/plugins/json_export.py
@@ -5,9 +5,7 @@
 
 @app.exporter(".json")
 def export_json(cfm: CFM) -> bytes:
-    root_feature = cfm.features[0]
-
-    serialized_root = serialize_feature(root_feature)
+    serialized_root = serialize_feature(cfm.root)
     serialized_constraints = list(
         map(serialize_constraint, [*cfm.require_constraints, *cfm.exclude_constraints])
     )
diff --git a/cfmtoolbox/plugins/json_import.py b/cfmtoolbox/plugins/json_import.py
index 9245278..774a642 100644
--- a/cfmtoolbox/plugins/json_import.py
+++ b/cfmtoolbox/plugins/json_import.py
@@ -20,7 +20,7 @@ def parse_cfm(serialized_cfm: JSON) -> CFM:
             f"CFM constraints must be a list: {serialized_cfm['constraints']}"
         )
 
-    features = parse_root(serialized_cfm["root"])
+    root, features = parse_root(serialized_cfm["root"])
 
     constraints = [
         parse_constraint(serialized_constraint, features)
@@ -31,13 +31,13 @@ def parse_cfm(serialized_cfm: JSON) -> CFM:
     exclude_constraints = list(filter(lambda c: not c.require, constraints))
 
     return CFM(
-        features=features,
+        root=root,
         require_constraints=require_constraints,
         exclude_constraints=exclude_constraints,
     )
 
 
-def parse_root(serialized_root: JSON) -> list[Feature]:
+def parse_root(serialized_root: JSON) -> tuple[Feature, list[Feature]]:
     root = parse_feature(serialized_root, parent=None)
 
     features = [root]
@@ -45,7 +45,7 @@ def parse_root(serialized_root: JSON) -> list[Feature]:
     for feature in features:
         features.extend(feature.children)
 
-    return features
+    return root, features
 
 
 def parse_feature(serialized_feature: JSON, /, parent: Feature | None) -> Feature:
diff --git a/cfmtoolbox/plugins/one_wise_sampling.py b/cfmtoolbox/plugins/one_wise_sampling.py
index a01d53b..08260a9 100644
--- a/cfmtoolbox/plugins/one_wise_sampling.py
+++ b/cfmtoolbox/plugins/one_wise_sampling.py
@@ -48,7 +48,7 @@ def __init__(self, model: CFM):
         self.model = model
 
     def one_wise_sampling(self) -> list[FeatureNode]:
-        self.calculate_border_assignments(self.model.features[0])
+        self.calculate_border_assignments(self.model.root)
 
         samples = []
 
@@ -75,9 +75,9 @@ def generate_valid_sample(self):
         while True:
             self.global_feature_count = defaultdict(int)
             self.covered_assignments = set()
-            self.covered_assignments.add((self.model.features[0].name, 1))
+            self.covered_assignments.add((self.model.root.name, 1))
             random_feature_node = self.generate_random_feature_node_with_assignment(
-                self.model.features[0]
+                self.model.root
             )
             if (
                 random_feature_node.validate(self.model)
diff --git a/cfmtoolbox/plugins/random_sampling.py b/cfmtoolbox/plugins/random_sampling.py
index 8b7e63a..bf996b6 100644
--- a/cfmtoolbox/plugins/random_sampling.py
+++ b/cfmtoolbox/plugins/random_sampling.py
@@ -34,9 +34,7 @@ def __init__(self, model: CFM):
     def random_sampling(self) -> FeatureNode:
         while True:
             self.global_feature_count = defaultdict(int)
-            random_feature_node = self.generate_random_feature_node(
-                self.model.features[0]
-            )
+            random_feature_node = self.generate_random_feature_node(self.model.root)
             if random_feature_node.validate(self.model):
                 break
 
diff --git a/cfmtoolbox/plugins/uvl_export.py b/cfmtoolbox/plugins/uvl_export.py
index 2078ef6..034b59d 100644
--- a/cfmtoolbox/plugins/uvl_export.py
+++ b/cfmtoolbox/plugins/uvl_export.py
@@ -139,13 +139,11 @@ def serialize_all_constraints(
 
 @app.exporter(".uvl")
 def export_uvl(cfm: CFM) -> bytes:
-    root_feature = cfm.features[0]
-
     includes = serialize_includes()
-    root = serialize_root_feature(root_feature)
+    root = serialize_root_feature(cfm.root)
 
     feature_strings = [
-        indent(serialize_features(child), "\t\t\t") for child in root_feature.children
+        indent(serialize_features(child), "\t\t\t") for child in cfm.root.children
     ]
 
     features = "".join(feature_strings) + "\n"
diff --git a/cfmtoolbox/plugins/uvl_import.py b/cfmtoolbox/plugins/uvl_import.py
index 026e399..71ec300 100644
--- a/cfmtoolbox/plugins/uvl_import.py
+++ b/cfmtoolbox/plugins/uvl_import.py
@@ -31,8 +31,13 @@ class ConstraintType(Enum):
 
 
 class CustomListener(UVLPythonListener):
-    def __init__(self, cfm: CFM):
-        self.cfm = cfm
+    def __init__(
+        self,
+        exported_features: list[Feature],
+        exported_require_constraints: list[Constraint],
+    ):
+        self.exported_features = exported_features
+        self.exported_require_constraints = exported_require_constraints
         self.references: list[str] = []
         self.feature_cardinalities: list[Cardinality] = []
         self.features: list[Feature] = []
@@ -141,7 +146,7 @@ def exitFeature(self, ctx: UVLPythonParser.FeatureContext):
             )
             self.feature_map[name] = feature
             self.features.append(feature)
-            self.cfm.features.append(feature)
+            self.exported_features.append(feature)
             if len(self.group_features_count) > 0:
                 self.group_features_count[-1] += 1
         else:
@@ -204,7 +209,7 @@ def exitFeature(self, ctx: UVLPythonParser.FeatureContext):
                         features,
                     )
                     parent_feature.children.append(feature)
-                    self.cfm.require_constraints.append(
+                    self.exported_require_constraints.append(
                         Constraint(
                             True,
                             parent_feature,
@@ -230,15 +235,17 @@ def exitFeature(self, ctx: UVLPythonParser.FeatureContext):
                     [
                         Interval(
                             min_cardinality,
-                            max_cardinality
-                            if max_cardinality is not None and max_cardinality > 0
-                            else None,
+                            (
+                                max_cardinality
+                                if max_cardinality is not None and max_cardinality > 0
+                                else None
+                            ),
                         )
                     ]
                 )
                 self.feature_map[name] = parent_feature
                 self.features.append(parent_feature)
-                self.cfm.features.append(parent_feature)
+                self.exported_features.append(parent_feature)
                 self.groups = self.groups[:-new_groups]
                 if len(self.group_features_count) > 0:
                     self.group_features_count[-1] += 1
@@ -282,7 +289,7 @@ def exitFeature(self, ctx: UVLPythonParser.FeatureContext):
                     child.parent = feature
                 self.feature_map[name] = feature
                 self.features.append(feature)
-                self.cfm.features.append(feature)
+                self.exported_features.append(feature)
                 if len(self.group_features_count) > 0:
                     self.group_features_count[-1] += 1
 
@@ -313,7 +320,7 @@ def exitConstraintLine(self, ctx: UVLPythonParser.ConstraintLineContext):
         op = self.constraint_types.pop()
 
         if op == ConstraintType.IMPLICATION:
-            self.cfm.require_constraints.append(
+            self.exported_require_constraints.append(
                 Constraint(
                     True,
                     self.feature_map[ref_1],
@@ -323,7 +330,7 @@ def exitConstraintLine(self, ctx: UVLPythonParser.ConstraintLineContext):
                 )
             )
         elif op == ConstraintType.EQUIVALENCE:
-            self.cfm.require_constraints.append(
+            self.exported_require_constraints.append(
                 Constraint(
                     True,
                     self.feature_map[ref_1],
@@ -332,7 +339,7 @@ def exitConstraintLine(self, ctx: UVLPythonParser.ConstraintLineContext):
                     Cardinality([Interval(1, None)]),
                 )
             )
-            self.cfm.require_constraints.append(
+            self.exported_require_constraints.append(
                 Constraint(
                     True,
                     self.feature_map[ref_2],
@@ -380,12 +387,17 @@ def import_uvl(data: bytes):
     token_stream = CommonTokenStream(lexer)
     parser = UVLPythonParser(token_stream)
 
-    cfm = CFM([], [], [])
+    exported_features: list[Feature] = []
+    exported_require_constraints: list[Constraint] = []
 
-    listener = CustomListener(cfm)
+    listener = CustomListener(exported_features, exported_require_constraints)
     parser.removeErrorListeners()
     parser.addErrorListener(CustomErrorListener())
     parser.addParseListener(listener)
     parser.featureModel()  # start parsing
 
-    return cfm
+    return CFM(
+        root=exported_features[0],
+        require_constraints=exported_require_constraints,
+        exclude_constraints=[],
+    )
diff --git a/tests/plugins/test_big_m.py b/tests/plugins/test_big_m.py
index bb3f941..5caa822 100644
--- a/tests/plugins/test_big_m.py
+++ b/tests/plugins/test_big_m.py
@@ -30,7 +30,7 @@ def test_apply_big_m_with_loaded_model(model: CFM):
 
 
 def test_get_global_upper_bound(model: CFM):
-    feature = model.features[0]
+    feature = model.root
     assert big_m.get_global_upper_bound(feature) == 12
 
 
diff --git a/tests/plugins/test_debugging.py b/tests/plugins/test_debugging.py
index 00b04b8..964121e 100644
--- a/tests/plugins/test_debugging.py
+++ b/tests/plugins/test_debugging.py
@@ -108,7 +108,7 @@ def test_stringify_cfm():
     )
 
     cfm = CFM(
-        [feature],
+        feature,
         [Constraint(True, feature, Cardinality([]), feature, Cardinality([]))],
         [],
     )
diff --git a/tests/plugins/test_featureide_import.py b/tests/plugins/test_featureide_import.py
index 13899ef..efdea5d 100644
--- a/tests/plugins/test_featureide_import.py
+++ b/tests/plugins/test_featureide_import.py
@@ -30,7 +30,7 @@ def test_featureide_import():
     path = Path("tests/data/sandwich.xml")
     cfm = import_featureide(path.read_bytes())
     assert len(cfm.features) == 11
-    assert cfm.features[0].name == "Sandwich"
+    assert cfm.root.name == "Sandwich"
 
 
 @pytest.mark.parametrize(
@@ -205,8 +205,9 @@ def test_parse_root():
     assert struct is not None
 
     root_struct = struct[0]
-    feature_list = parse_root(root_struct)
+    root_feature, feature_list = parse_root(root_struct)
 
+    assert root_feature.name == "Sandwich"
     assert len(feature_list) == 11
     assert feature_list[0].name == "Sandwich"
     assert feature_list[1].name == "Bread"
diff --git a/tests/plugins/test_json_export.py b/tests/plugins/test_json_export.py
index 2f2acb9..4fe2853 100644
--- a/tests/plugins/test_json_export.py
+++ b/tests/plugins/test_json_export.py
@@ -21,7 +21,7 @@ def test_export_json():
     )
 
     cfm = CFM(
-        features=[root],
+        root=root,
         require_constraints=[],
         exclude_constraints=[],
     )
diff --git a/tests/plugins/test_json_import.py b/tests/plugins/test_json_import.py
index 784f5a7..b0ff676 100644
--- a/tests/plugins/test_json_import.py
+++ b/tests/plugins/test_json_import.py
@@ -16,7 +16,7 @@ def test_import_json():
     path = Path("tests/data/sandwich.json")
     cfm = json_import.import_json(path.read_bytes())
     assert len(cfm.features) == 12
-    assert cfm.features[0].name == "sandwich"
+    assert cfm.root.name == "sandwich"
 
 
 @pytest.mark.parametrize(
@@ -119,7 +119,7 @@ def test_parse_cfm_parses_root_and_constraints():
 
 
 def test_parse_root_returns_all_features_in_the_tree():
-    features = json_import.parse_root(
+    root, features = json_import.parse_root(
         {
             "name": "sandwich",
             "instance_cardinality": {"intervals": []},
@@ -159,6 +159,7 @@ def test_parse_root_returns_all_features_in_the_tree():
         }
     )
 
+    assert root.name == "sandwich"
     assert len(features) == 5
     assert features[0].name == "sandwich"
     assert features[1].name == "meat"
diff --git a/tests/plugins/test_uvl_import.py b/tests/plugins/test_uvl_import.py
index a577e0d..fda47fa 100644
--- a/tests/plugins/test_uvl_import.py
+++ b/tests/plugins/test_uvl_import.py
@@ -4,15 +4,13 @@
 import pytest
 
 import cfmtoolbox.plugins.uvl_import as uvl_import_plugin
-from cfmtoolbox import CFM
-from cfmtoolbox.models import Cardinality, Constraint, Feature, Interval
+from cfmtoolbox import Cardinality, CFMToolbox, Constraint, Feature, Interval
 from cfmtoolbox.plugins.uvl_import import ConstraintType, CustomListener
-from cfmtoolbox.toolbox import CFMToolbox
 
 
 @pytest.fixture()
 def listener():
-    return CustomListener(CFM([], [], []))
+    return CustomListener([], [])
 
 
 def test_plugin_can_be_loaded():
@@ -379,7 +377,7 @@ def test_exit_feature_with_two_groups(listener):
     assert len(listener.features) == 1
     assert listener.features[0].name == "test"
 
-    mock_parent = copy.deepcopy(listener.cfm.require_constraints[0].first_feature)
+    mock_parent = copy.deepcopy(listener.exported_require_constraints[0].first_feature)
 
     feature1 = Feature(
         name="test_0",
@@ -400,7 +398,7 @@ def test_exit_feature_with_two_groups(listener):
     )
 
     mock_parent.children = [feature1, feature2]
-    for child in listener.cfm.require_constraints[0].first_feature.children:
+    for child in listener.exported_require_constraints[0].first_feature.children:
         child.parent = mock_parent
 
     assert listener.features[0].parent is None
@@ -411,15 +409,15 @@ def test_exit_feature_with_two_groups(listener):
     )
     assert listener.feature_map["test"] == listener.features[0]
     assert len(listener.groups) == 0
-    assert len(listener.cfm.require_constraints) == 2
-    assert listener.cfm.require_constraints[0] == Constraint(
+    assert len(listener.exported_require_constraints) == 2
+    assert listener.exported_require_constraints[0] == Constraint(
         require=True,
         first_feature=mock_parent,
         first_cardinality=Cardinality([Interval(1, None)]),
         second_feature=feature1,
         second_cardinality=Cardinality([Interval(1, None)]),
     )
-    assert listener.cfm.require_constraints[1] == Constraint(
+    assert listener.exported_require_constraints[1] == Constraint(
         require=True,
         first_feature=mock_parent,
         first_cardinality=Cardinality([Interval(1, None)]),
@@ -487,7 +485,7 @@ def test_exit_feature_with_two_groups_and_instance_cardinality(listener):
     assert len(listener.features) == 1
     assert listener.features[0].name == "test"
 
-    mock_parent = copy.deepcopy(listener.cfm.require_constraints[0].first_feature)
+    mock_parent = copy.deepcopy(listener.exported_require_constraints[0].first_feature)
 
     feature1 = Feature(
         name="test_0",
@@ -508,7 +506,7 @@ def test_exit_feature_with_two_groups_and_instance_cardinality(listener):
     )
 
     mock_parent.children = [feature1, feature2]
-    for child in listener.cfm.require_constraints[0].first_feature.children:
+    for child in listener.exported_require_constraints[0].first_feature.children:
         child.parent = mock_parent
 
     assert listener.features[0].parent is None
@@ -519,15 +517,15 @@ def test_exit_feature_with_two_groups_and_instance_cardinality(listener):
     )
     assert listener.feature_map["test"] == listener.features[0]
     assert listener.group_features_count == [1]
-    assert len(listener.cfm.require_constraints) == 2
-    assert listener.cfm.require_constraints[0] == Constraint(
+    assert len(listener.exported_require_constraints) == 2
+    assert listener.exported_require_constraints[0] == Constraint(
         require=True,
         first_feature=mock_parent,
         first_cardinality=Cardinality([Interval(1, None)]),
         second_feature=feature1,
         second_cardinality=Cardinality([Interval(1, None)]),
     )
-    assert listener.cfm.require_constraints[1] == Constraint(
+    assert listener.exported_require_constraints[1] == Constraint(
         require=True,
         first_feature=mock_parent,
         first_cardinality=Cardinality([Interval(1, None)]),
@@ -594,7 +592,7 @@ def test_exit_feature_with_two_groups_including_group_cardinality(listener):
     assert len(listener.features) == 1
     assert listener.features[0].name == "test"
 
-    mock_parent = copy.deepcopy(listener.cfm.require_constraints[0].first_feature)
+    mock_parent = copy.deepcopy(listener.exported_require_constraints[0].first_feature)
 
     feature1 = Feature(
         name="test_0",
@@ -615,7 +613,7 @@ def test_exit_feature_with_two_groups_including_group_cardinality(listener):
     )
 
     mock_parent.children = [feature1, feature2]
-    for child in listener.cfm.require_constraints[0].first_feature.children:
+    for child in listener.exported_require_constraints[0].first_feature.children:
         child.parent = mock_parent
 
     assert listener.features[0].parent is None
@@ -626,15 +624,15 @@ def test_exit_feature_with_two_groups_including_group_cardinality(listener):
     )
     assert listener.feature_map["test"] == listener.features[0]
     assert listener.group_features_count == [1]
-    assert len(listener.cfm.require_constraints) == 2
-    assert listener.cfm.require_constraints[0] == Constraint(
+    assert len(listener.exported_require_constraints) == 2
+    assert listener.exported_require_constraints[0] == Constraint(
         require=True,
         first_feature=mock_parent,
         first_cardinality=Cardinality([Interval(1, None)]),
         second_feature=feature1,
         second_cardinality=Cardinality([Interval(1, None)]),
     )
-    assert listener.cfm.require_constraints[1] == Constraint(
+    assert listener.exported_require_constraints[1] == Constraint(
         require=True,
         first_feature=mock_parent,
         first_cardinality=Cardinality([Interval(1, None)]),
@@ -703,7 +701,7 @@ def test_exit_feature_with_two_groups_including_group_cardinality_with_instances
     assert len(listener.features) == 1
     assert listener.features[0].name == "test"
 
-    mock_parent = copy.deepcopy(listener.cfm.require_constraints[0].first_feature)
+    mock_parent = copy.deepcopy(listener.exported_require_constraints[0].first_feature)
 
     feature1 = Feature(
         name="test_0",
@@ -724,7 +722,7 @@ def test_exit_feature_with_two_groups_including_group_cardinality_with_instances
     )
 
     mock_parent.children = [feature1, feature2]
-    for child in listener.cfm.require_constraints[0].first_feature.children:
+    for child in listener.exported_require_constraints[0].first_feature.children:
         child.parent = mock_parent
 
     assert listener.features[0].parent is None
@@ -735,15 +733,15 @@ def test_exit_feature_with_two_groups_including_group_cardinality_with_instances
     )
     assert listener.feature_map["test"] == listener.features[0]
     assert listener.group_features_count == [1]
-    assert len(listener.cfm.require_constraints) == 2
-    assert listener.cfm.require_constraints[0] == Constraint(
+    assert len(listener.exported_require_constraints) == 2
+    assert listener.exported_require_constraints[0] == Constraint(
         require=True,
         first_feature=mock_parent,
         first_cardinality=Cardinality([Interval(1, None)]),
         second_feature=feature1,
         second_cardinality=Cardinality([Interval(1, None)]),
     )
-    assert listener.cfm.require_constraints[1] == Constraint(
+    assert listener.exported_require_constraints[1] == Constraint(
         require=True,
         first_feature=mock_parent,
         first_cardinality=Cardinality([Interval(1, None)]),
@@ -795,7 +793,7 @@ def test_exit_features_with_one_group_with_group_cardinality(listener):
     )
     assert listener.feature_map["test"] == listener.features[0]
     assert listener.group_features_count == [1]
-    assert len(listener.cfm.require_constraints) == 0
+    assert len(listener.exported_require_constraints) == 0
 
 
 def test_exit_group_spec_one_subfeature(listener):
@@ -1238,7 +1236,7 @@ def test_exit_constraint_line_equivalence(listener):
 
     listener.exitConstraintLine(mock_ctx)
 
-    assert len(listener.cfm.require_constraints) == 2
+    assert len(listener.exported_require_constraints) == 2
 
 
 def test_exit_constraint_line_implication(listener):
@@ -1266,7 +1264,7 @@ def test_exit_constraint_line_implication(listener):
 
     listener.exitConstraintLine(mock_ctx)
 
-    assert len(listener.cfm.require_constraints) == 1
+    assert len(listener.exported_require_constraints) == 1
 
 
 def test_exit_features(listener):
diff --git a/tests/test_models.py b/tests/test_models.py
index 0098675..39ddf62 100644
--- a/tests/test_models.py
+++ b/tests/test_models.py
@@ -168,41 +168,19 @@ def test_feature_is_unbound(feature: Feature, expectation: bool):
     assert feature.is_unbound() is expectation
 
 
-def test_add_feature():
-    cfm = CFM([], [], [])
-    feature = Feature(
-        "Cheese", Cardinality([]), Cardinality([]), Cardinality([]), None, []
-    )
-    cfm.add_feature(feature)
-    assert feature in cfm.features
-
-
-def test_add_feature_ignores_already_added_features():
-    cfm = CFM([], [], [])
-    feature = Feature(
-        "Cheese", Cardinality([]), Cardinality([]), Cardinality([]), None, []
-    )
-    cfm.add_feature(feature)
-    cfm.add_feature(feature)
-    assert len(cfm.features) == 1
-    assert feature in cfm.features
-
-
 @pytest.mark.parametrize(
     ["cfm", "expectation"],
     [
         (
             CFM(
-                [
-                    Feature(
-                        "Cheese",
-                        Cardinality([Interval(0, None)]),
-                        Cardinality([]),
-                        Cardinality([]),
-                        None,
-                        [],
-                    )
-                ],
+                Feature(
+                    "Cheese",
+                    Cardinality([Interval(0, None)]),
+                    Cardinality([]),
+                    Cardinality([]),
+                    None,
+                    [],
+                ),
                 [],
                 [],
             ),
@@ -210,16 +188,14 @@ def test_add_feature_ignores_already_added_features():
         ),
         (
             CFM(
-                [
-                    Feature(
-                        "Cheese",
-                        Cardinality([Interval(0, 4)]),
-                        Cardinality([]),
-                        Cardinality([]),
-                        None,
-                        [],
-                    )
-                ],
+                Feature(
+                    "Cheese",
+                    Cardinality([Interval(0, 4)]),
+                    Cardinality([]),
+                    Cardinality([]),
+                    None,
+                    [],
+                ),
                 [],
                 [],
             ),
@@ -470,7 +446,7 @@ def test_validate_feature_instance(feature_instance: FeatureNode, expectation: b
             ),
         ],
     )
-    cfm = CFM([feature], [], [])
+    cfm = CFM(feature, [], [])
     assert feature_instance.validate(cfm) == expectation
 
 
@@ -759,5 +735,8 @@ def test_validate_constraints(
         ],
     )
 
-    cfm = CFM([], require_constraints, exclude_constraints)
+    dummy_root = Feature(
+        "Dummy", Cardinality([]), Cardinality([]), Cardinality([]), None, []
+    )
+    cfm = CFM(dummy_root, require_constraints, exclude_constraints)
     assert feature_instance.validate_constraints(cfm) == expectation
diff --git a/tests/test_toolbox.py b/tests/test_toolbox.py
index f7f27d0..78fc039 100644
--- a/tests/test_toolbox.py
+++ b/tests/test_toolbox.py
@@ -3,8 +3,19 @@
 import pytest
 import typer
 
-from cfmtoolbox import CFM
-from cfmtoolbox.toolbox import CFMToolbox
+from cfmtoolbox import CFM, Cardinality, CFMToolbox, Feature
+
+
+@pytest.fixture
+def root_feature():
+    return Feature(
+        name="root",
+        instance_cardinality=Cardinality([]),
+        group_type_cardinality=Cardinality([]),
+        group_instance_cardinality=Cardinality([]),
+        parent=None,
+        children=[],
+    )
 
 
 def test_import_model_without_import_path():
@@ -26,12 +37,12 @@ def test_import_model_without_matching_importer(tmp_path: Path):
     assert app.model is None
 
 
-def test_import_model_with_matching_importer(tmp_path: Path):
+def test_import_model_with_matching_importer(tmp_path: Path, root_feature):
     app = CFMToolbox()
     app.import_path = tmp_path / "test.uvl"
     app.import_path.touch()
 
-    cfm = CFM([], [], [])
+    cfm = CFM(root_feature, [], [])
     assert app.model is not cfm
 
     @app.importer(".uvl")
@@ -49,18 +60,18 @@ def test_export_model_without_export_path():
     app.export_model()
 
 
-def test_export_model_without_matching_exporter(tmp_path: Path):
+def test_export_model_without_matching_exporter(tmp_path: Path, root_feature):
     app = CFMToolbox()
-    app.model = CFM([], [], [])
+    app.model = CFM(root_feature, [], [])
     app.export_path = tmp_path / "test.txt"
 
     with pytest.raises(typer.Abort, match="Unsupported export format"):
         app.export_model()
 
 
-def test_export_model_with_matching_exporter(tmp_path: Path):
+def test_export_model_with_matching_exporter(tmp_path: Path, root_feature):
     app = CFMToolbox()
-    app.model = CFM([], [], [])
+    app.model = CFM(root_feature, [], [])
     app.export_path = tmp_path / "test.uvl"
 
     @app.exporter(".uvl")
@@ -71,12 +82,12 @@ def export_uvl(cfm: CFM):
     assert app.export_path.read_text() == "hello"
 
 
-def test_importer_registration():
+def test_importer_registration(root_feature):
     app = CFMToolbox()
 
     @app.importer(".uvl")
     def import_uvl(data: bytes):
-        return CFM([], [], [])
+        return CFM(root_feature, [], [])
 
     assert len(app.registered_importers) == 1
     assert app.registered_importers[".uvl"] == import_uvl