Be able to get test coverage of the XRP ledger

[lisv]

Following the meeting on the 4th of January:

• Compile XRP Ledger with test coverage enabled
• Idea: start program from IDE itself (and use a coverage tool)

[lisv]

Following the meeting on the 18th of January:

• Option 1: compile in IDE in a VM
• Option 2: run docker image and compile in there
• Option 3: compile from source code on VM
• Option 4: fork project and use TravisCI
• Look at travis yml file to see how rippled enables test coverage

[lisv]

Update:

• Tried running the source code in a IDE in VM -> crashed around 83% progress
• Tried compiling from source with coverage -> Using my VM this resulted in a crash around 83% (tried multiple times, resulted in failure message or whole VM crash).
• Tried to fork and get TravisCI compiled version -> unsuccesful, all builds fail

• Tried to use the rippled docker image using Docker Desktop and Ubuntu on Windows -> did not get it to work (yet)

• On a laptop running Linux it compiled successfully (using tags used in travis yml file), but looking at the coverage report it did not work - coverage files were not generated. Also not after running Ripple's unit tests.
• Compiling by running the Test.py file in the repo (rather than following the building from source manual) with the correct flags worked on a Linux laptop! Resulted in a branch coverage of 8% when only running the server, 44% after running rippled unit tests.
• It is possible to run the tests from the tool against the server on the same Linux laptop, but no significant difference in branch coverage