Set up pytest and coverage tooling

tests/unit/test_site.py

@@ -0,0 +1,19 @@
+from pathlib import Path
+import pytest
+from omicron.ssg.site import Site
+
+
+@pytest.mark.parametrize(
+    "value, expected_origin, expected_path",
+    [
+        (None, "", Path("/")),
+        ("http://example.com/blog", "http://example.com", Path("/blog")),
+        ("http://example.com", "http://example.com", Path("/")),
+        ("//example.com/blog", "//example.com", Path("/blog")),
+        ("/blog", "", Path("/blog")),
+    ],
+)
+def test_parse_base_url(value, expected_origin, expected_path):
+    origin, path = Site.parse_base_url(value)
+    assert origin == expected_origin
+    assert path == expected_path