diff --git a/.github/workflows/linux_cuda_wheel.yaml b/.github/workflows/linux_cuda_wheel.yaml
index 61d6f50d0..2b39fee44 100644
--- a/.github/workflows/linux_cuda_wheel.yaml
+++ b/.github/workflows/linux_cuda_wheel.yaml
@@ -138,7 +138,7 @@ jobs:
           ls
       - name: Run Python tests
         run: |
-          ${CONDA_RUN} FAIL_WITHOUT_CUDA=1 pytest test -v --tb=short
+          ${CONDA_RUN} FAIL_WITHOUT_CUDA=1 pytest --override-ini="addopts=-v" test --tb=short
       - name: Run Python benchmark
         run: |
           ${CONDA_RUN} time python benchmarks/decoders/gpu_benchmark.py --devices=cuda:0,cpu --resize_devices=none
diff --git a/.github/workflows/linux_wheel.yaml b/.github/workflows/linux_wheel.yaml
index 1855e904e..706e7c2b4 100644
--- a/.github/workflows/linux_wheel.yaml
+++ b/.github/workflows/linux_wheel.yaml
@@ -123,4 +123,4 @@ jobs:
           ls
       - name: Run Python tests
         run: |
-          pytest test -vvv
+          pytest --override-ini="addopts=-v" test
diff --git a/.github/workflows/macos_wheel.yaml b/.github/workflows/macos_wheel.yaml
index ee436b7a4..b26a1d2d1 100644
--- a/.github/workflows/macos_wheel.yaml
+++ b/.github/workflows/macos_wheel.yaml
@@ -122,4 +122,4 @@ jobs:
 
       - name: Run Python tests
         run: |
-          pytest test -vvv
+          pytest --override-ini="addopts=-v" test
diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index f91be9a89..b8d815eec 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -55,10 +55,11 @@ pip install -e ".[dev]" --no-build-isolation -vv
 To run python tests run:
 
 ```bash
-pytest test -vvv
+pytest
 ```
 
-Tip: use the `-k "not slow"` flag to skip slow tests.
+Some tests are marked as 'slow' and aren't run by default. You can use `pytest
+-m slow` to run those, or `pytest -m ""` to run all tests, slow or not.
 
 To run the C++ tests run:
 
diff --git a/pyproject.toml b/pyproject.toml
index 98c5473e7..2f8b4da45 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -39,3 +39,15 @@ target-version = ["py38"]
 excludes = [
     "examples",
 ]
+
+[tool.pytest.ini_options]
+markers = [
+    # defines a 'slow' mark to mark slow tests with `@pytest.mark.slow`
+    "slow: mark test as slow"
+]
+
+# We don't want to run the slow tests by default. These options are ignored in
+# the CI, where we definitely want the 'slow' tests to run.
+addopts = "-v -m 'not slow'"
+
+testpaths = ["test"]
diff --git a/test/test_decoders.py b/test/test_decoders.py
index 2a48c28c3..d7f53dee3 100644
--- a/test/test_decoders.py
+++ b/test/test_decoders.py
@@ -422,6 +422,7 @@ def test_iteration(self, device, seek_mode):
             elif i == 389:
                 assert_frames_equal(ref_frame_last, frame)
 
+    @pytest.mark.slow
     def test_iteration_slow(self):
         decoder = VideoDecoder(NASA_VIDEO.path)
         ref_frame_last = NASA_VIDEO.get_frame_data_by_index(389)