Add snippet test 3

docs/tutorials/single.md

@@ -12,7 +12,7 @@ It is recommended to use MLflow's functionality in your training workflow, which
 First, an environment must be created with the appropriate Python version and necessary packages/libraries (please see the [quickstart](../quickstart.html) page for guidance on setting one up). 
 We can then import the libraries necessary to train our model:
 ```python
-{% include _includes/includesnippet filename='modelScripts/testfile.py' starttext='from sklearn.model_selection' endtext='import RandomForestRegressor' %}
+{% include _includes/includesnippet filename='modelScripts/train_sklearn.py' starttext='from sklearn.model_selection' endtext='import RandomForestRegressor' %}
 ```
 
 We import MLflow and activate the _autolog_ feature: