EP: Implement compile validation and e2e

tests/e2e/require_ep.py

@@ -68,3 +68,24 @@ def require_ep(ep: str) -> str:
         pytest.skip(f"EP not available on this host: {provider}")
 
     return provider
+
+
+def require_not_ep(ep: str) -> None:
+    """Skip the current test unless the requested EP is NOT available.
+
+    Mirror of :func:`require_ep` for tests that exercise the
+    "EP not registered" rejection path (e.g. ``winml compile --ep qnn``
+    on a host without QNN).
+    """
+    from winml.modelkit.session import WinMLEPRegistry
+    from winml.modelkit.utils import normalize_ep_name
+
+    provider = normalize_ep_name(ep)
+    if provider is None:
+        pytest.skip(f"Unknown EP: {ep!r}")
+
+    if provider == "CPUExecutionProvider":
+        pytest.skip("CPU is always available on this host")
+
+    if WinMLEPRegistry.get_instance().is_ep_available(provider):
+        pytest.skip(f"EP is available on this host (test requires it absent): {provider}")