Test set for dataflow

[popthink]

Now Plume can produce dataflow edges.

For such things, Test set may be enhanced.

There is some way to make it.

1. Using algorithm of soot(Reaching Def)

2. Just checking them with "should ~"

[popthink]

Option 1 is not worth. Because of the comment @DavidBakerEffendi wrote in #127.
Soot doesn't over-approximate and let them tainted on every call.
Option 2 might be only option for checking data flow working properly.
Unless plume provide some own dataflow pass based on soot or something for cpg.

[DavidBakerEffendi]

So this might be a decent place to add another test set under the testing submodule since then we can use the Cpg API that is only available for Scala - which allows better graph traversals. I guess validating some small examples with basic dependencies should be good enough?

[popthink]

I agree 👍

[DavidBakerEffendi]

Created an issue under #160