diff --git a/tests/sample/collections/test_base_collection.py b/tests/sample/collections/test_base_collection.py
new file mode 100644
index 00000000..6b3624d7
--- /dev/null
+++ b/tests/sample/collections/test_base_collection.py
@@ -0,0 +1,81 @@
+from unittest.mock import MagicMock
+
+from easyreflectometry.sample.collections.base_collection import BaseCollection
+from easyreflectometry.sample.elements.layers.layer import Layer
+
+
+class TestBaseCollection:
+    def test_constructor(self):
+        # When
+        elem_1 = Layer(name='layer_1')
+        elem_2 = Layer(name='layer_2')
+        mock_interface = MagicMock()
+
+        # Then
+        p = BaseCollection('name', mock_interface, elem_1, elem_2)
+
+        # Expect
+        p._interface = mock_interface
+        len(p) == 2
+
+    def test_names(self):
+        # When
+        elem_1 = Layer(name='layer_1')
+        elem_2 = Layer(name='layer_2')
+        mock_interface = MagicMock()
+
+        # Then
+        p = BaseCollection('name', mock_interface, elem_1, elem_2)
+
+        # Expect
+        assert p.names == ['layer_1', 'layer_2']
+
+    def test_dict_repr(self):
+        # When
+        elem = Layer(name='layer')
+        mock_interface = MagicMock()
+
+        # Then
+        p = BaseCollection('name', mock_interface, elem)
+
+        # Expect
+        assert p._dict_repr == {
+            'name': [
+                {
+                    'layer': {
+                        'material': {'EasyMaterial': {'isld': '0.000e-6 1/Å^2', 'sld': '4.186e-6 1/Å^2'}},
+                        'roughness': '3.300 Å',
+                        'thickness': '10.000 Å',
+                    }
+                }
+            ]
+        }
+
+    def test_as_dict(self):
+        # When
+        elem = Layer(name='layer')
+        mock_interface = MagicMock()
+
+        # Then
+        p = BaseCollection('name', mock_interface, elem)
+
+        # Expect
+        assert p.as_dict()['name'] == 'name'
+        assert len(p.as_dict()['data']) == 1
+        assert p.as_dict()['data'][0]['name'] == 'layer'
+
+    def test_make_default_collection(self):
+        # When
+        elem_1 = Layer(name='layer_1')
+        mock_interface_1 = MagicMock()
+        elem_2 = Layer(name='layer_2')
+        mock_interface_2 = MagicMock()
+        p = BaseCollection('name', mock_interface_1, elem_1)
+
+        # Then
+        default_collection = p._make_default_collection([elem_2], mock_interface_2)
+
+        # Expect
+        assert default_collection[0] != elem_2
+        assert default_collection[0].name == 'layer_2'
+        assert default_collection[0].interface == mock_interface_2