use test.pypi.org via env variable (#1296)

Signed-off-by: guschmue <[email protected]>

Author: guschmue

ci_build/azure_pipelines/templates/setup.yml

@@ -12,7 +12,11 @@ steps:
     then
         pip install $(CI_PIP_ONNX_NAME) $(CI_PIP_ONNX_BACKEND_NAME) numpy --no-deps -U
     fi
-
+    if [[ $ONNX_TEST ==  "true" ]] ;
+    then
+      pip uninstall -y onnx
+      pip install --index-url https://test.pypi.org/simple/ onnx
+    fi
     if [[ $CI_ONNXRUNTIME_NIGHTLY == "true" ]] ;
     then
       pip uninstall -y onnxruntime