diff --git a/micropip/wheelinfo.py b/micropip/wheelinfo.py
index c6d255f..8c77cbf 100644
--- a/micropip/wheelinfo.py
+++ b/micropip/wheelinfo.py
@@ -54,6 +54,7 @@ class WheelInfo:
     _dist_info: Path | None = None
 
     def __post_init__(self):
+        assert self.url.startswith("http"), self.url
         self._project_name = safe_name(self.name)
 
     @classmethod
diff --git a/tests/conftest.py b/tests/conftest.py
index af55b88..c704a57 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -270,7 +270,7 @@ def add_pkg_version(
         releases[version] = [
             {
                 "filename": filename,
-                "url": filename,
+                "url": f"http://fake.domain/f/{filename}",
                 "digests": {
                     "sha256": Wildcard(),
                 },
diff --git a/tests/test_install.py b/tests/test_install.py
index 111926a..aa89b0e 100644
--- a/tests/test_install.py
+++ b/tests/test_install.py
@@ -257,7 +257,7 @@ def _mock_fetch_bytes(arg, *args, **kwargs):
 
     msg = "Access-Control-Allow-Origin"
     with pytest.raises(ValueError, match=msg):
-        await micropip.install("htps://x.com/xxx-1.0.0-py3-none-any.whl")
+        await micropip.install("https://x.com/xxx-1.0.0-py3-none-any.whl")
 
 
 @pytest.mark.skip_refcount_check