Add test for a warning with '0.90' since there is '0.90-2' available

Author: Kim

tests/unit/test_amazon_estimator.py

@@ -495,6 +495,10 @@ def test_get_xgboost_image_uri_warning_with_legacy(caplog):
     get_image_uri(REGION, "xgboost", 1)
     assert "There is a more up to date SageMaker XGBoost image." in caplog.text
 
+def test_get_xgboost_image_uri_warning_with_no_sagemaker_version(caplog):
+    get_image_uri(REGION, "xgboost", "0.90")
+    assert "There is a more up to date SageMaker XGBoost image." in caplog.text
+
 
 def test_get_xgboost_image_uri_no_warning_with_latest(caplog):
     get_image_uri(REGION, "xgboost", XGBOOST_LATEST_VERSION.split("-")[0])