diff --git a/.github/workflows/format.yaml b/.github/workflows/format.yaml
index 7e4ded3e..b0680061 100644
--- a/.github/workflows/format.yaml
+++ b/.github/workflows/format.yaml
@@ -8,7 +8,8 @@ jobs:
       fail-fast: false
       matrix:
         python-version: ["3.11"]
-        os: [macos-latest, windows-latest, ubuntu-latest]
+        # os: [macos-latest, windows-latest, ubuntu-latest]
+        os: [ubuntu-latest]
     runs-on: ${{ matrix.os }}
 
     steps:
diff --git a/.github/workflows/lint.yaml b/.github/workflows/lint.yaml
index 2591fed7..dd72b8c4 100644
--- a/.github/workflows/lint.yaml
+++ b/.github/workflows/lint.yaml
@@ -8,7 +8,7 @@ jobs:
       fail-fast: false
       matrix:
         python-version: ["3.7", "3.8", "3.9", "3.10", "3.11", "3.12"]
-        os: [macos-latest, windows-latest, ubuntu-latest]
+        os: [ubuntu-latest]
     runs-on: ${{ matrix.os }}
 
     steps:
diff --git a/.github/workflows/self_test.yaml b/.github/workflows/self_test.yaml
index bad470c2..25f83d6b 100644
--- a/.github/workflows/self_test.yaml
+++ b/.github/workflows/self_test.yaml
@@ -8,7 +8,7 @@ jobs:
       fail-fast: false
       matrix:
         python-version: ["3.7", "3.8", "3.9", "3.10", "3.11"]
-        os: [macos-latest, windows-latest, ubuntu-latest]
+        os: [ubuntu-latest]
     runs-on: ${{ matrix.os }}
 
     steps:
diff --git a/tests/utils.py b/tests/utils.py
index 417bf9de..46361aca 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -101,9 +101,16 @@ def unused_factory(*deps: str) -> List[UnusedDependency]:
     return [UnusedDependency(dep, [Location(Path("foo"))]) for dep in deps]
 
 
+def _config_file_name():
+    if sys.platform.startswith("win"):
+        return Path("nul")
+    else:
+        return Path("/dev/null")
+
+
 def run_fawltydeps_subprocess(
     *args: str,
-    config_file: Path = Path("/dev/null"),
+    config_file: Path = _config_file_name(),
     to_stdin: Optional[str] = None,
     cwd: Optional[Path] = None,
 ) -> Tuple[str, str, int]: