diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index d4773a7..02bc7c7 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -19,8 +19,8 @@ jobs:
           architecture: x64
       - name: Install dependencies
         run: |
-          python -m pip install --upgrade pip setuptools numpy
-          pip install --progress-bar off -r requirements-dev.txt
+          python -m pip install --upgrade pip setuptools
+          pip install --progress-bar off numpy matplotlib scipy mypy flake8 black
       - run: flake8 . --show-source --statistics
       - run: black --check .
       - run: mypy cmaes
diff --git a/benchmark/problem_rastrigin.py b/benchmark/problem_rastrigin.py
index 14f7bc4..da9ac12 100644
--- a/benchmark/problem_rastrigin.py
+++ b/benchmark/problem_rastrigin.py
@@ -39,7 +39,7 @@ def create_problem(self, seed: int) -> Problem:
 
     def specification(self) -> problem.ProblemSpec:
         params = [
-            problem.Var(f"x{i+1}", problem.ContinuousRange(-5.12, 5.12))
+            problem.Var(f"x{i + 1}", problem.ContinuousRange(-5.12, 5.12))
             for i in range(self.dim)
         ]
         return problem.ProblemSpec(