diff --git a/tests/ebuild/test_build_dir_resolution.py b/tests/ebuild/test_build_dir_resolution.py
index 28d9eb3..43f17e9 100644
--- a/tests/ebuild/test_build_dir_resolution.py
+++ b/tests/ebuild/test_build_dir_resolution.py
@@ -26,6 +26,7 @@
 from __future__ import annotations
 
 import os
+import shutil
 import subprocess
 import textwrap
 from pathlib import Path
@@ -243,8 +244,8 @@ def test_configure_and_build_from_outside_agree_on_the_build_dir(
 
 
 @pytest.mark.skipif(
-    subprocess.run(["gcc", "--version"], capture_output=True).returncode != 0,
-    reason="needs a working gcc to link the executable",
+    shutil.which("gcc") is None,
+    reason="needs gcc on PATH to link the executable",
 )
 def test_end_to_end_build_from_outside_produces_the_binary(tmp_path, monkeypatch):
     """No stubs: the real ninja run must produce the real executable."""
diff --git a/tests/unit/test_footprint.py b/tests/unit/test_footprint.py
index 5450853..3e20168 100644
--- a/tests/unit/test_footprint.py
+++ b/tests/unit/test_footprint.py
@@ -15,6 +15,7 @@
 """
 
 import os
+import shutil
 import subprocess
 from pathlib import Path
 
@@ -55,8 +56,12 @@ def test_a_pure_bss_buffer_costs_ram_but_not_flash(self):
         assert fp.flash == 100
         assert fp.ram == 8192
 
-
 class TestMeasure:
+    @pytest.mark.skipif(
+        shutil.which("gcc") is None or find_size_tool() is None,
+        reason="needs gcc and a size tool",
+    )
+
     def test_measures_a_real_binary(self, tmp_path):
         src = tmp_path / "m.c"
         src.write_text("static char buf[4096];\nint main(void){return buf[0];}\n")