diff --git a/.github/workflows/black.yml b/.github/workflows/black.yml
new file mode 100644
index 0000000..6f5581a
--- /dev/null
+++ b/.github/workflows/black.yml
@@ -0,0 +1,11 @@
+name: python-black
+on: [push, pull_request]
+jobs:
+  linter_name:
+    name: runner / black formatter
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+      - uses: rickstaa/action-black@v1
+        with:
+          black_args: ". --check"
diff --git a/.github/workflows/cocotb.yml b/.github/workflows/cocotb.yml
new file mode 100644
index 0000000..d44af32
--- /dev/null
+++ b/.github/workflows/cocotb.yml
@@ -0,0 +1,17 @@
+name: cocotb
+on: [push, pull_request]
+jobs:
+  cocotb-container:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Checkout code
+        uses: actions/checkout@v4
+      - name: Run pytest in container
+        uses: addnab/docker-run-action@v3
+        with:
+          image: ghcr.io/builderdev212/cocotb-runner:latest
+          options: -v ${{ github.workspace }}:/usr/src/verilogbits
+          run: |
+            . .venv/bin/activate && /bin/bash
+            cd verilogbits
+            pytest
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
deleted file mode 100644
index eb77eb0..0000000
--- a/.github/workflows/main.yml
+++ /dev/null
@@ -1,26 +0,0 @@
-name: python-black
-on: [push, pull_request]
-jobs:
-  linter_name:
-    name: runner / black formatter
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@v4
-      - uses: rickstaa/action-black@v1
-        with:
-          black_args: ". --check"
-
-name: CI
-on:
-  push:
-    branches: [ main ]
-jobs:
-  container-test-job:
-    runs-on: debian:12-slim
-    container: 
-      image: ghcr.io/builderdev212/cocotb-runner
-      volumes:
-        - ${PWD}:/usr/src/verilogbits
-    steps:
-      - name: Run testbenches
-        run: cd verilogbits && pytest -n 10
diff --git a/problems/getting-started/output-zero/tb/constant_zero.py b/problems/getting-started/output-zero/tb/constant_zero.py
index b953983..1b45d94 100644
--- a/problems/getting-started/output-zero/tb/constant_zero.py
+++ b/problems/getting-started/output-zero/tb/constant_zero.py
@@ -21,4 +21,6 @@ def get_signals(self):
 
     async def zero_check(self):
         if int(self.zero.value) != 0:
-            raise DataError(f"Output should always be 0, got {self.zero.value} instead.")
+            raise DataError(
+                f"Output should always be 0, got {self.zero.value} instead."
+            )