diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index 590fd48..dcb2bc5 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -21,10 +21,6 @@ repos:
   rev: 2.1.3
   hooks:
   - id: pyproject-fmt
-- repo: https://github.com/tox-dev/tox-ini-fmt
-  rev: 1.3.1
-  hooks:
-  - id: tox-ini-fmt
 - repo: https://github.com/google/yamlfmt
   rev: v0.12.1
   hooks:
diff --git a/pyproject.toml b/pyproject.toml
index 0fb0358..33dbb54 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -70,6 +70,33 @@ lint.isort.force-sort-within-sections = true
 lint.isort.order-by-type = false
 lint.pydocstyle.convention = "google"
 
+[tool.tox]
+legacy_tox_ini = """
+    [tox]
+    requires =
+        tox>=4.2
+    env_list =
+        py
+
+    [testenv]
+    system_site_packages = true
+    deps =
+        covdefaults
+        coverage
+        moto[s3]
+        pytest
+    commands =
+        coverage erase
+        coverage run -m pytest {posargs}
+        coverage report
+
+    [coverage:run]
+    plugins = covdefaults
+    source =
+        btrfs2s3
+        tests
+"""
+
 [tool.mypy]
 mypy_path = "typeshed"
 strict = true