diff --git a/.devcontainer/devcontainer.json b/.devcontainer/devcontainer.json
index 44bcdbf..4fa2451 100644
--- a/.devcontainer/devcontainer.json
+++ b/.devcontainer/devcontainer.json
@@ -17,13 +17,12 @@
       "settings": {
         // Discover the tests/ package from the Test Explorer.
         "python.testing.unittestEnabled": true,
-        "python.testing.unittestArgs": ["-v", "-s", ".", "-p", "test*.py"]
+        "python.testing.unittestArgs": ["-v", "-s", "tests", "-p", "test*.py"]
       }
     }
   },
 
-  // Compile + install the extension (non-editable: a clean .so in site-packages
-  // avoids the name clash with the list_reserve/ stub package) and add the
-  // `build` frontend so `python -m build` works.
-  "postCreateCommand": "pip install --upgrade pip && pip install . build"
+  // Compile + install the package in editable mode and add the `build` frontend
+  // so `python -m build` works.
+  "postCreateCommand": "pip install --upgrade pip && pip install -e . build"
 }
diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 55fc16d..08bdc90 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -47,4 +47,4 @@ jobs:
         pip install .
     - name: Test
       run: |
-        python -m unittest
+        python tools/run_installed_tests.py
diff --git a/MANIFEST.in b/MANIFEST.in
index 62c45b5..d4ffb39 100644
--- a/MANIFEST.in
+++ b/MANIFEST.in
@@ -2,4 +2,5 @@
 # from a PyPI source download. The tests/ package is not part of the wheel
 # (packages = ["list_reserve"]), so the sdist is its only distribution channel.
 recursive-include tests *.py
+include tools/run_installed_tests.py
 include LICENSE
diff --git a/README.md b/README.md
index 386a3c0..4aa99e0 100644
--- a/README.md
+++ b/README.md
@@ -102,12 +102,12 @@ supports Dev Containers ("Reopen in Container"), or run it headlessly with the
 
 ```bash
 devcontainer up --workspace-folder .
-devcontainer exec --workspace-folder . python -m unittest
+devcontainer exec --workspace-folder . python tools/run_installed_tests.py
 ```
 
-The container compiles the C extension on creation, so the tests are runnable immediately.
-Since `list_reserve` is a C extension, re-run `pip install .` after editing
-`src/list_reserve.c`.
+The container installs the package in editable mode on creation, so the tests are
+runnable immediately. Since `list_reserve` includes a C extension, re-run
+`pip install -e .` after editing `src/list_reserve.c`.
 
 ## License
 
diff --git a/list_reserve/__init__.py b/list_reserve/__init__.py
new file mode 100644
index 0000000..0fb6140
--- /dev/null
+++ b/list_reserve/__init__.py
@@ -0,0 +1,9 @@
+from ._list_reserve import allocated_bytes, capacity, reserve, shrink_to_fit, stats
+
+__all__ = [
+    "allocated_bytes",
+    "capacity",
+    "reserve",
+    "shrink_to_fit",
+    "stats",
+]
diff --git a/pyproject.toml b/pyproject.toml
index d7baffa..620713c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -84,14 +84,9 @@ build = "cp310-* cp311-* cp312-* cp313-* cp314-*"
 #   internals.
 skip = "pp* *t-*"
 
-# cibuildwheel runs this against each installed wheel from a temp dir, so it
-# tests the installed .so. `-s {project}` makes {project} the discovery
-# top-level dir, so tests import as `tests.*` and `from tests._support import
-# ...` resolves; `-s {project}/tests` would drop the `tests.` prefix and break
-# that import. Quote the glob with double quotes (honored by both POSIX sh and
-# Windows cmd; single quotes reach unittest literally on Windows and match
-# nothing) so unittest, not the shell, expands it.
-test-command = "python -m unittest discover -s {project} -p \"test_*.py\""
+# Run tests from outside the source tree so `import list_reserve` resolves to the
+# installed wheel instead of the local package directory.
+test-command = "python \"{project}/tools/run_installed_tests.py\""
 
 # Windows ARM64 is experimental and its tests cannot run on the build host, so
 # skip them (the wheel is still built and shipped).
diff --git a/setup.py b/setup.py
index dab794f..202b60a 100644
--- a/setup.py
+++ b/setup.py
@@ -5,6 +5,6 @@
 # [tool.setuptools.ext-modules] table cannot yet express stably.
 setup(
     ext_modules=[
-        Extension("list_reserve", ["src/list_reserve.c"]),
+        Extension("list_reserve._list_reserve", ["src/list_reserve.c"]),
     ],
 )
diff --git a/src/list_reserve.c b/src/list_reserve.c
index a9d2cd1..1e298c3 100644
--- a/src/list_reserve.c
+++ b/src/list_reserve.c
@@ -183,11 +183,11 @@ static PyMethodDef methods[] = {
     {NULL}};
 
 // module definition struct
-static struct PyModuleDef module = {PyModuleDef_HEAD_INIT, "list_reserve",
+static struct PyModuleDef module = {PyModuleDef_HEAD_INIT, "list_reserve._list_reserve",
                                     "list memory allocation library", -1, methods};
 
 // Initializes module
 PyMODINIT_FUNC
-PyInit_list_reserve(void) {
+PyInit__list_reserve(void) {
     return PyModule_Create(&module);
 }
diff --git a/tools/run_installed_tests.py b/tools/run_installed_tests.py
new file mode 100644
index 0000000..b3dfa55
--- /dev/null
+++ b/tools/run_installed_tests.py
@@ -0,0 +1,38 @@
+from __future__ import annotations
+
+import shutil
+import sys
+import tempfile
+import unittest
+from pathlib import Path
+
+
+def main() -> int:
+    project_root = Path(__file__).resolve().parents[1]
+    source_tests = project_root / "tests"
+
+    with tempfile.TemporaryDirectory(prefix="list-reserve-tests-") as tmp:
+        tmp_path = Path(tmp)
+        copied_tests = tmp_path / "tests"
+        shutil.copytree(
+            source_tests,
+            copied_tests,
+            ignore=shutil.ignore_patterns("__pycache__"),
+        )
+
+        sys.path = [
+            entry for entry in sys.path if Path(entry or ".").resolve() != project_root
+        ]
+        sys.path.insert(0, str(tmp_path))
+
+        suite = unittest.defaultTestLoader.discover(
+            str(copied_tests),
+            pattern="test_*.py",
+            top_level_dir=str(tmp_path),
+        )
+        result = unittest.TextTestRunner(verbosity=2).run(suite)
+        return int(not result.wasSuccessful())
+
+
+if __name__ == "__main__":
+    raise SystemExit(main())