diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 18de92b9..1ef97526 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -75,6 +75,9 @@ jobs:
           python -m pip install tox
       - name: Run
         run: tox
+      - name: Check diff coverage
+        if: ${{ matrix.python == '3.11' && matrix.platform == 'ubuntu-latest' }}
+        run: tox -e diffcov
 
   docs:
     runs-on: ubuntu-latest
diff --git a/tox.ini b/tox.ini
index ac720699..9b678ef6 100644
--- a/tox.ini
+++ b/tox.ini
@@ -3,7 +3,7 @@ deps =
 setenv =
 	PYTHONWARNDEFAULTENCODING = 1
 commands =
-	pytest {posargs}
+	pytest {posargs} --cov-report xml
 passenv =
 	HOME
 usedevelop = True
@@ -24,7 +24,6 @@ commands =
 deps =
 	diff-cover
 commands =
-	pytest {posargs} --cov-report xml
 	diff-cover coverage.xml --compare-branch=origin/main --html-report diffcov.html
 	diff-cover coverage.xml --compare-branch=origin/main --fail-under=100