diff --git a/tests/test_extends.py b/tests/test_extends.py
index ef8f755..0bc6a0c 100644
--- a/tests/test_extends.py
+++ b/tests/test_extends.py
@@ -5,18 +5,20 @@ from compose_viz.extends import Extends
 
 def test_extend_init_normal() -> None:
     try:
-        Extends(service_name="frontend", from_file="tests/in/000001.yaml")
+        e = Extends(service_name="frontend", from_file="tests/in/000001.yaml")
 
-        assert True
+        assert e.service_name == "frontend"
+        assert e.from_file == "tests/in/000001.yaml"
     except Exception as e:
         assert False, e
 
 
 def test_extend_init_without_from_file() -> None:
     try:
-        Extends(service_name="frontend")
+        e = Extends(service_name="frontend")
 
-        assert True
+        assert e.service_name == "frontend"
+        assert e.from_file is None
     except Exception as e:
         assert False, e
 
diff --git a/tests/test_volume.py b/tests/test_volume.py
new file mode 100644
index 0000000..a58b56e
--- /dev/null
+++ b/tests/test_volume.py
@@ -0,0 +1,23 @@
+from compose_viz.volume import Volume, VolumeType
+
+
+def test_extend_init_normal() -> None:
+    try:
+        v = Volume(source="./foo", target="./bar")
+
+        assert v.source == "./foo"
+        assert v.target == "./bar"
+        assert v.type == VolumeType.volume
+    except Exception as e:
+        assert False, e
+
+
+def test_extend_with_type() -> None:
+    try:
+        v = Volume(source="./foo", target="./bar", type=VolumeType.bind)
+
+        assert v.source == "./foo"
+        assert v.target == "./bar"
+        assert v.type == VolumeType.bind
+    except Exception as e:
+        assert False, e