Consolidate test site fixture into a single make_site

tests/unit/conftest.py

@@ -1,8 +1,20 @@
+import shutil
+from pathlib import Path
 import pytest
 from omicron.ssg.site import Site
 
+DATA_SITES = Path(__file__).parent.parent / "data" / "sites"
+
 
 @pytest.fixture
-def thin_site(tmp_path):
-    (tmp_path / "config.yml").write_text("name: test\ntemplate: plain\n")
-    return Site(tmp_path)
+def make_site(tmp_path):
+    def _make(name, **kwargs):
+        site_dir = tmp_path / name
+        shutil.copytree(
+            DATA_SITES / name,
+            site_dir,
+            ignore=shutil.ignore_patterns("output", "build.log"),
+        )
+        return Site(site_dir, **kwargs)
+
+    return _make