add opentelemetry test dependency

Author: wangzlei

tox.ini

@@ -38,6 +38,7 @@ commands_pre =
   test: pip install "opentelemetry-sdk[test] @ {env:CORE_REPO}#egg=opentelemetry-sdk&subdirectory=opentelemetry-sdk"
   test: pip install "opentelemetry-instrumentation[test] @ {env:CONTRIB_REPO}#egg=opentelemetry-instrumentation&subdirectory=opentelemetry-instrumentation"
   test: pip install "opentelemetry-exporter-otlp[test] @ {env:CORE_REPO}#egg=opentelemetry-exporter-otlp&subdirectory=exporter/opentelemetry-exporter-otlp"
+  test: pip install "opentelemetry-test-utils @ {env:CORE_REPO}#egg=opentelemetry-test-utils&subdirectory=tests/opentelemetry-test-utils"
   aws-opentelemetry-distro: pip install {toxinidir}/aws-opentelemetry-distro
 
 commands =