If you create a file in your Drive named "HelloWorld" and you then make the following API Call, https://www.googleapis.com/drive/v2/files?q=title+contains+'World' the file does not come up in the results.
- It works properly on ?fullText+contains+'World'
- It also works on ?title+contains+'HelloW'
This is the expected behavior.
"title contains <substring>"
queries are not supported. This is also true for the search functionality on the Google Drive front-end.