diff --git a/.travis.yml b/.travis.yml
index 0d3fcaf33..578b05f9a 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -28,7 +28,7 @@ jobs:
       name: "Pre-commit Check"
       script:
         - docker build --target dev -t elasticdl:dev -f elasticdl/docker/Dockerfile .
-        - docker run --rm -it -v $PWD:/work -w /work elasticdl:dev bash -c "pre-commit run --files $(find elasticdl/python model_zoo setup.py scripts/ -name '*.py' -print0 | tr '\0' ' ') $(find elasticdl/pkg -name '*.go' -print0 | tr '\0' ' ')"
+        - docker run --rm -it -v $PWD:/work -w /work elasticdl:dev bash -c "pre-commit run --files $(find elasticdl/python elasticdl_preprocessing model_zoo setup.py scripts/ -name '*.py' -print0 | tr '\0' ' ') $(find elasticdl/pkg -name '*.go' -print0 | tr '\0' ' ')"
     - stage: tests
       name: "Tests"
       script:
diff --git a/elasticdl_preprocessing/layers/__init__.py b/elasticdl_preprocessing/layers/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/elasticdl_preprocessing/tests/__init__.py b/elasticdl_preprocessing/tests/__init__.py
new file mode 100644
index 000000000..e69de29bb
diff --git a/scripts/unittest.sh b/scripts/unittest.sh
index 47092ad8c..74bfef7fe 100755
--- a/scripts/unittest.sh
+++ b/scripts/unittest.sh
@@ -9,5 +9,5 @@ go test -v -cover ./...
 popd
 
 # Python unittests
-K8S_TESTS=True pytest elasticdl/python/tests --cov=elasticdl/python --cov-report=xml
+K8S_TESTS=True pytest elasticdl/python/tests elasticdl_preprocessing/tests --cov=elasticdl/python --cov-report=xml
 mv coverage.xml shared
\ No newline at end of file