Showing interesting/relevant test suites when debugging

[soyapark]

As some participants point out from our past deployment (#164), we just take 5 latest emails from selected folders which are sometimes not relevant to users' code and it hampers users to debug their code properly.

As for string properties of Message and Contact, we can override them with our custom Str type and when users try to check equality or compare, we can log other value and use it for query relevant messages.

class MyStr(str):
  def __eq__(self, other):
    # Store `other` value to query

resource: https://www.pythondoeswhat.com/2011/01/custom-string-class.html