diff --git a/.coveragerc b/.coveragerc
deleted file mode 100644
index 1553bae2..00000000
--- a/.coveragerc
+++ /dev/null
@@ -1,13 +0,0 @@
-[run]
-branch = True
-source = sleepecg
-omit =
-    */examples/*
-    */setup.py
-
-[report]
-exclude_lines =
-    pragma: no cover
-    if __name__ == .__main__.:
-    @abstractmethod
-    @abstractclassmethod
diff --git a/pyproject.toml b/pyproject.toml
index e57cc8c4..68f6cbfb 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -51,6 +51,7 @@ dev = [  # everything needed for development
     "mypy >= 0.991",
     "pre-commit >= 2.13.0",
     "pytest >= 6.2.0",
+    "pytest-cov >= 6.0.0",
     "ruff >= 0.4.0",
     "setuptools >= 56.0.0",
 ]
@@ -85,7 +86,7 @@ build = "cp39-*"  # abi3
 select = "*"
 inherit.repair-wheel-command = "append"
 repair-wheel-command = [
-  "pipx run abi3audit --strict --report {wheel}",
+    "pipx run abi3audit --strict --report {wheel}",
 ]
 
 [tool.cibuildwheel.linux]
@@ -99,9 +100,13 @@ archs = "x86_64 arm64"
 archs = "AMD64"
 before-build = "pip install delvewheel"
 repair-wheel-command = [
-  "delvewheel repair -w {dest_dir} {wheel}",
+    "delvewheel repair -w {dest_dir} {wheel}",
 ]
 
+[tool.coverage.run]
+branch = true
+source = ["src/sleepecg"]
+
 [tool.mypy]
 ignore_missing_imports = true
 disallow_untyped_defs = true
@@ -116,6 +121,7 @@ filterwarnings = [
     'ignore:.*datetime.datetime.utcfromtimestamp\(\):DeprecationWarning',
     'ignore:(?s).*Pyarrow:DeprecationWarning',
 ]
+addopts = "--cov"
 
 [tool.ruff]
 line-length = 92