diff --git a/.github/workflows/python-tests.yml b/.github/workflows/python-tests.yml
index c01e0161..d87bdf50 100644
--- a/.github/workflows/python-tests.yml
+++ b/.github/workflows/python-tests.yml
@@ -18,8 +18,9 @@ jobs:
           architecture: x64
       - name: Install dependencies
         run: |
-          python -m pip install --upgrade pip setuptools
-          pip install --progress-bar off .[lint]
+          python -m pip install --progress-bar off --upgrade pip setuptools
+          pip install --progress-bar off .
+          pip install --progress-bar off flake8 black isort mypy
       - run: flake8 . --show-source
       - run: black --check --diff .
       - run: isort --check --diff .
@@ -37,5 +38,7 @@ jobs:
           python-version: ${{ matrix.python-version }}
           architecture: x64
       - name: Install dependencies
-        run: pip install --progress-bar off .
+        run: |
+          python -m pip install --progress-bar off --upgrade pip setuptools
+          pip install --progress-bar off .
       - run: python -m unittest
diff --git a/DEVELOPMENT.md b/DEVELOPMENT.md
index 453c698b..bd80f7d3 100644
--- a/DEVELOPMENT.md
+++ b/DEVELOPMENT.md
@@ -70,10 +70,21 @@ $ pip install tox
 $ tox -e py39
 ```
 
+### Running visual regression tests using pyppeteer
+
+Please run following commands, then check screenshots in `tmp/` directory.
+
+```
+$ pip install -r requirements.txt
+$ python visual_regression_test.py --output-dir tmp
+```
+
+Note: When you run pyppeteer for the first time, it downloads the latest version of Chromium (~150MB) if it is not found on your system.
+
 ### Linters (flake8, black and mypy)
 
 ```
-$ pip install .[lint]
+$ pip install -r requirements.txt
 $ flake8
 $ black --check .
 $ isort . --check
diff --git a/requirements.txt b/requirements.txt
new file mode 100644
index 00000000..6d49d55a
--- /dev/null
+++ b/requirements.txt
@@ -0,0 +1,14 @@
+# project dependency
+optuna>=2.4
+bottle
+typing-extensions;python_version<'3.8'
+scikit-learn
+
+# lint
+black
+flake8
+isort
+mypy
+
+# test
+pyppeteer
diff --git a/setup.cfg b/setup.cfg
index 1ae34112..3cd04ed6 100644
--- a/setup.cfg
+++ b/setup.cfg
@@ -32,13 +32,6 @@ install_requires =
     typing-extensions;python_version<'3.8'
     scikit-learn
 
-[options.extras_require]
-lint =
-    black
-    isort
-    mypy
-    flake8
-
 [options.entry_points]
 console_scripts =
     optuna-dashboard = optuna_dashboard.cli:main
diff --git a/tox.ini b/tox.ini
index dd77fb99..91a17ef3 100644
--- a/tox.ini
+++ b/tox.ini
@@ -35,7 +35,7 @@ commands = black --check . {posargs}
 
 [testenv:isort]
 deps = isort
-commands = isort . --check
+commands = isort . --check {posargs}
 
 [testenv:mypy]
 deps = mypy