diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index a3501211..c4ec7f96 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -38,7 +38,7 @@ jobs:
       env:
         PYTEST_ADDOPTS: "--durations=0"
       run: |
-        hatch test --cover
+        hatch test -m "" --cover # override default exclusion of slow tests with -m ""
 
   docs:
     runs-on: ubuntu-latest
diff --git a/pyproject.toml b/pyproject.toml
index a4041a78..9d60ac7c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -48,6 +48,9 @@ Changelog = "https://github.com/C2SM/Sirocco/blob/main/CHANGELOG.md"
 # Configuration for [pytest](https://docs.pytest.org)
 addopts = "--pdbcls=IPython.terminal.debugger:TerminalPdb"
 norecursedirs = "tests/cases"
+markers = [
+  "slow: slow integration tests which are not recommended to run locally for normal development"
+]
 
 [tool.coverage.run]
 # Configuration of [coverage.py](https://coverage.readthedocs.io)
@@ -83,7 +86,7 @@ extra-dependencies = [
     "ipdb"
 ]
 default-args = []
-extra-args = ["--doctest-modules"]
+extra-args = ["--doctest-modules", '-m not slow']
 
 [[tool.hatch.envs.hatch-test.matrix]]
 python = ["3.12"]
diff --git a/src/sirocco/core/workflow.py b/src/sirocco/core/workflow.py
index 13f856ea..c394ad4a 100644
--- a/src/sirocco/core/workflow.py
+++ b/src/sirocco/core/workflow.py
@@ -116,7 +116,7 @@ def from_config_file(cls: type[Self], config_path: str) -> Self:
         return cls.from_config_workflow(ConfigWorkflow.from_config_file(config_path))
 
     @classmethod
-    def from_config_workflow(cls: type[Self], config_workflow: ConfigWorkflow) -> Workflow:
+    def from_config_workflow(cls: type[Self], config_workflow: ConfigWorkflow) -> Self:
         return cls(
             name=config_workflow.name,
             config_rootdir=config_workflow.rootdir,
diff --git a/tests/test_wc_workflow.py b/tests/test_wc_workflow.py
index 23dfceee..3649d6d8 100644
--- a/tests/test_wc_workflow.py
+++ b/tests/test_wc_workflow.py
@@ -69,6 +69,7 @@ def test_vizgraph(config_paths):
 
 
 # configs that are tested for running workgraph
+@pytest.mark.slow
 @pytest.mark.parametrize(
     "config_path",
     [