diff --git a/tests/test_internals_urls.py b/tests/test_internals_urls.py
new file mode 100644
index 0000000000..deac632105
--- /dev/null
+++ b/tests/test_internals_urls.py
@@ -0,0 +1,88 @@
+from datasette.app import Datasette
+from .fixtures import app_client_with_hash
+import pytest
+
+
+@pytest.fixture(scope="module")
+def ds():
+    return Datasette([], memory=True)
+
+
+@pytest.mark.parametrize(
+    "base_url,path,expected",
+    [
+        ("/", "/", "/"),
+        ("/", "/foo", "/foo"),
+        ("/prefix/", "/", "/prefix/"),
+        ("/prefix/", "/foo", "/prefix/foo"),
+        ("/prefix/", "foo", "/prefix/foo"),
+    ],
+)
+def test_path(ds, base_url, path, expected):
+    ds._config["base_url"] = base_url
+    assert ds.urls.path(path) == expected
+
+
+@pytest.mark.parametrize(
+    "base_url,expected",
+    [
+        ("/", "/"),
+        ("/prefix/", "/prefix/"),
+    ],
+)
+def test_instance(ds, base_url, expected):
+    ds._config["base_url"] = base_url
+    assert ds.urls.instance() == expected
+
+
+@pytest.mark.parametrize(
+    "base_url,file,expected",
+    [
+        ("/", "foo.js", "/-/static/foo.js"),
+        ("/prefix/", "foo.js", "/prefix/-/static/foo.js"),
+    ],
+)
+def test_static(ds, base_url, file, expected):
+    ds._config["base_url"] = base_url
+    assert ds.urls.static(file) == expected
+
+
+@pytest.mark.parametrize(
+    "base_url,expected",
+    [
+        ("/", "/-/logout"),
+        ("/prefix/", "/prefix/-/logout"),
+    ],
+)
+def test_logout(ds, base_url, expected):
+    ds._config["base_url"] = base_url
+    assert ds.urls.logout() == expected
+
+
+@pytest.mark.parametrize("base_url,expected", [
+    ("/", "/:memory:"),
+    ("/prefix/", "/prefix/:memory:"),
+])
+def test_database(ds, base_url, expected):
+    ds._config["base_url"] = base_url
+    assert ds.urls.database(":memory:") == expected
+    # Do table and query while we are here
+    assert ds.urls.table(":memory:", "name") == expected + "/name"
+    assert ds.urls.query(":memory:", "name") == expected + "/name"
+
+
+@pytest.mark.parametrize("base_url", ["/", "/prefix/"])
+def test_database_hashed(app_client_with_hash, base_url):
+    ds = app_client_with_hash.ds
+    original_base_url = ds._config["base_url"]
+    try:
+        ds._config["base_url"] = base_url
+        db_hash = ds.get_database("fixtures").hash
+        assert len(db_hash) == 64
+        expected = "{}fixtures-{}".format(base_url, db_hash[:7])
+        assert ds.urls.database("fixtures") == expected
+        assert ds.urls.table("fixtures", "name") == expected + "/name"
+        assert ds.urls.query("fixtures", "name") == expected + "/name"
+    finally:
+        # Reset this since fixture is shared with other tests
+        ds._config["base_url"] = original_base_url