diff --git a/pyproject.toml b/pyproject.toml
index e0834d0..f27f552 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -19,6 +19,9 @@ dev = [
     "rich>=14.3.3",
     "ruff>=0.15.2",
 ]
+test = [
+    "pytest>=9.0.2",
+]
 
 [tool.ruff]
 line-length = 120
diff --git a/tests/test_sequence.py b/tests/test_sequence.py
new file mode 100644
index 0000000..681bceb
--- /dev/null
+++ b/tests/test_sequence.py
@@ -0,0 +1,70 @@
+from __future__ import annotations
+
+from typing import Any
+
+from hooked_containers.sequence import HookedList
+
+
+def get_id(a: Any):
+    return str(hex(id(a)))
+
+
+class TestHookedList:
+    class TestConstruction:
+        def test_empty(self):
+            lst = HookedList(None, existing=[])
+            assert list(lst) == []
+
+        def test_with_items(self):
+            lst = HookedList(None, existing=[1, 2, 3])
+            assert list(lst) == [1, 2, 3]
+
+        def test_recreation(self):
+            initial = [1, 2, 3]
+            initial_id = id(initial)
+
+            lst = HookedList(None, existing=initial)
+            assert id(lst._data) == initial_id
+
+            lst2 = HookedList(None, existing=lst)
+            assert id(lst2._data) == initial_id
+
+    class TestSeqOps:
+        def test_len(self):
+            lst = HookedList(None, existing=[1, 2, 3])
+            assert len(lst) == 3
+
+        def test_getitem(self):
+            lst = HookedList(None, existing=[1, 2, 3])
+            assert lst[0] == 1
+            assert lst[1] == 2
+            assert lst[-1] == 3
+
+        def test_contains(self):
+            lst = HookedList(None, existing=[1, 2, 3])
+            assert 2 in lst
+            assert 4 not in lst
+
+        def test_iter(self):
+            lst = HookedList(None, existing=[1, 2, 3])
+            for i, item in enumerate(lst, start=1):
+                assert item == i
+
+    class TestMutableOps:
+        def test_setitem(self):
+            added = []
+            lst = HookedList(lambda e: added.append(e.item), existing=[1, 2, 3])
+            lst[0] = 10
+            lst.append(20)
+            assert list(lst) == [10, 2, 3, 20]
+            assert added == [10, 20]
+
+        def test_delitem(self):
+            lst = HookedList(None, existing=[1, 2, 3])
+            del lst[1]
+            assert list(lst) == [1, 3]
+
+        def test_insert(self):
+            lst = HookedList(None, existing=[1, 3])
+            lst.insert(1, 2)
+            assert list(lst) == [1, 2, 3]
diff --git a/uv.lock b/uv.lock
index c7e3a33..53ea0b7 100644
--- a/uv.lock
+++ b/uv.lock
@@ -145,6 +145,9 @@ dev = [
     { name = "rich" },
     { name = "ruff" },
 ]
+test = [
+    { name = "pytest" },
+]
 
 [package.metadata]
 
@@ -154,6 +157,16 @@ dev = [
     { name = "rich", specifier = ">=14.3.3" },
     { name = "ruff", specifier = ">=0.15.2" },
 ]
+test = [{ name = "pytest", specifier = ">=9.0.2" }]
+
+[[package]]
+name = "iniconfig"
+version = "2.3.0"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/72/34/14ca021ce8e5dfedc35312d08ba8bf51fdd999c576889fc2c24cb97f4f10/iniconfig-2.3.0.tar.gz", hash = "sha256:c76315c77db068650d49c5b56314774a7804df16fee4402c1f19d6d15d8c4730", size = 20503, upload-time = "2025-10-18T21:55:43.219Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/cb/b1/3846dd7f199d53cb17f49cba7e651e9ce294d8497c8c150530ed11865bb8/iniconfig-2.3.0-py3-none-any.whl", hash = "sha256:f631c04d2c48c52b84d0d0549c99ff3859c98df65b3101406327ecc7d53fbf12", size = 7484, upload-time = "2025-10-18T21:55:41.639Z" },
+]
 
 [[package]]
 name = "ipykernel"
@@ -334,6 +347,15 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/48/31/05e764397056194206169869b50cf2fee4dbbbc71b344705b9c0d878d4d8/platformdirs-4.9.2-py3-none-any.whl", hash = "sha256:9170634f126f8efdae22fb58ae8a0eaa86f38365bc57897a6c4f781d1f5875bd", size = 21168, upload-time = "2026-02-16T03:56:08.891Z" },
 ]
 
+[[package]]
+name = "pluggy"
+version = "1.6.0"
+source = { registry = "https://pypi.org/simple" }
+sdist = { url = "https://files.pythonhosted.org/packages/f9/e2/3e91f31a7d2b083fe6ef3fa267035b518369d9511ffab804f839851d2779/pluggy-1.6.0.tar.gz", hash = "sha256:7dcc130b76258d33b90f61b658791dede3486c3e6bfb003ee5c9bfb396dd22f3", size = 69412, upload-time = "2025-05-15T12:30:07.975Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/54/20/4d324d65cc6d9205fabedc306948156824eb9f0ee1633355a8f7ec5c66bf/pluggy-1.6.0-py3-none-any.whl", hash = "sha256:e920276dd6813095e9377c0bc5566d94c932c33b27a3e3945d8389c374dd4746", size = 20538, upload-time = "2025-05-15T12:30:06.134Z" },
+]
+
 [[package]]
 name = "prompt-toolkit"
 version = "3.0.52"
@@ -410,6 +432,22 @@ wheels = [
     { url = "https://files.pythonhosted.org/packages/c7/21/705964c7812476f378728bdf590ca4b771ec72385c533964653c68e86bdc/pygments-2.19.2-py3-none-any.whl", hash = "sha256:86540386c03d588bb81d44bc3928634ff26449851e99741617ecb9037ee5ec0b", size = 1225217, upload-time = "2025-06-21T13:39:07.939Z" },
 ]
 
+[[package]]
+name = "pytest"
+version = "9.0.2"
+source = { registry = "https://pypi.org/simple" }
+dependencies = [
+    { name = "colorama", marker = "sys_platform == 'win32'" },
+    { name = "iniconfig" },
+    { name = "packaging" },
+    { name = "pluggy" },
+    { name = "pygments" },
+]
+sdist = { url = "https://files.pythonhosted.org/packages/d1/db/7ef3487e0fb0049ddb5ce41d3a49c235bf9ad299b6a25d5780a89f19230f/pytest-9.0.2.tar.gz", hash = "sha256:75186651a92bd89611d1d9fc20f0b4345fd827c41ccd5c299a868a05d70edf11", size = 1568901, upload-time = "2025-12-06T21:30:51.014Z" }
+wheels = [
+    { url = "https://files.pythonhosted.org/packages/3b/ab/b3226f0bd7cdcf710fbede2b3548584366da3b19b5021e74f5bde2a8fa3f/pytest-9.0.2-py3-none-any.whl", hash = "sha256:711ffd45bf766d5264d487b917733b453d917afd2b0ad65223959f59089f875b", size = 374801, upload-time = "2025-12-06T21:30:49.154Z" },
+]
+
 [[package]]
 name = "python-dateutil"
 version = "2.9.0.post0"