Improvements to longest-path-test
Improvements to longest-path-test

- Simplify object construction.
- Add another test.

kdawes/dagre,GerHobbelt/dagre,9n/dagre,9n/dagre,abduld/dagre,9n/dagre,lmcorbo/dagre,tylingsoft/dagre-layout,GerHobbelt/dagre,cpettitt/dagre,cpettitt/dagre,abduld/dagre,lmcorbo/dagre,shelsonjava/dagre,shelsonjava/dagre,lmcorbo/dagre,cpettitt/dagre,tylingsoft/dagre-layout,witcxc/dagre,shelsonjava/dagre,kdawes/dagre,witcxc/dagre,kdawes/dagre,GerHobbelt/dagre,abduld/dagre