[tests] add some slow tests

meanas/test/test_examples_smoke.py

@@ -0,0 +1,47 @@
+from pathlib import Path
+import os
+import subprocess
+import sys
+
+import pytest
+
+
+pytestmark = pytest.mark.complete
+
+REPO_ROOT = Path(__file__).resolve().parents[2]
+
+
+def _run_example(example_name: str, tmp_path: Path) -> subprocess.CompletedProcess[str]:
+    env = os.environ.copy()
+    env['MPLBACKEND'] = 'Agg'
+    env['MPLCONFIGDIR'] = str(tmp_path / f'mpl-{example_name}')
+    return subprocess.run(
+        [sys.executable, str(REPO_ROOT / 'examples' / example_name)],
+        cwd=REPO_ROOT,
+        env=env,
+        text=True,
+        capture_output=True,
+        check=False,
+        timeout=60,
+    )
+
+
+def test_eme_example_smoke_runs(tmp_path: Path) -> None:
+    pytest.importorskip('matplotlib')
+
+    result = _run_example('eme.py', tmp_path)
+
+    assert result.returncode == 0, result.stdout + result.stderr
+    assert 'left effective indices:' in result.stdout
+    assert 'fundamental left-to-right transmission' in result.stdout
+
+
+def test_eme_bend_example_smoke_runs(tmp_path: Path) -> None:
+    pytest.importorskip('matplotlib')
+    pytest.importorskip('skrf')
+
+    result = _run_example('eme_bend.py', tmp_path)
+
+    assert result.returncode == 0, result.stdout + result.stderr
+    assert 'straight effective indices:' in result.stdout
+    assert 'cascaded bend through power' in result.stdout