diff --git a/.gitignore b/.gitignore
index aba956b..b4cd2d4 100644
--- a/.gitignore
+++ b/.gitignore
@@ -3,6 +3,7 @@
 *.log
 *.py[cod]
 *~
+.coverage
 .DS_Store
 .hypothesis
 .idea
diff --git a/pyproject.toml b/pyproject.toml
index b0ed1a4..8e4516b 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -16,15 +16,17 @@ openapi-core = "^0.13.4"
 
 [tool.poetry.dev-dependencies]
 black = { version = "*", allow-prereleases = true }
+coverage = "*"
 mypy = "*"
 hypothesis = "*"
 flake8 = "*"
 pytest = "*"
+pytest-cov = "*"
 pytest-flake8 = "*"
 pytest-mypy = "*"
 
 [tool.pytest.ini_options]
-addopts = "--flake8 --mypy"
+addopts = "--cov=tornado_openapi3 --flake8 --mypy"
 
 [build-system]
 requires = ["poetry>=0.12"]
diff --git a/tox.ini b/tox.ini
index b519bb9..9cfa834 100644
--- a/tox.ini
+++ b/tox.ini
@@ -7,11 +7,16 @@ deps =
     tornado4: tornado>=4,<5
     tornado5: tornado>=5,<6
     tornado6: tornado>=6,<7
+    codecov
     mypy
     hypothesis
     flake8
     pytest
+    pytest-cov
     pytest-flake8
     pytest-mypy
+passenv = CI TRAVIS TRAVIS_*
 whitelist_externals = poetry
-commands = py.test
+commands =
+    pytest
+    codecov