This large refactor allows future re-use of the existing tests for `FrozenGraph`, which does not implement `GraphTopologyAddition`, but instead has to convert from a different graph which does.
- Fix tests for `GraphTopologyDeletion` hard-coding Graph instead of using the trait.
- Fix some tests silently depending on macro call site uses.
- Change `GraphTopologyAddition` tests to use `Default::default` instead of `new`.
- Add new tests for `GraphTopology::vertex_map` and `edge_map` that also depend on `GraphTopologyAddition`, removing these dependencies from the existing tests.
- Add new test macro `graph_topology_addition_deletion_tests` for tests that need deletion and addition.
ElementMap tests are now self contained unit tests, without any graph context. The only exception is the repurposed test "reused_slot_returns_old_value", which is not suited for GraphTopologyDeletion, but actually specific for Graph.
Use the already established macro pattern, move actual tests to a new file in src/testing.
Use the make_test_graph() function from the graph topology tests instead of duplicating it for the Dijkstra tests.
warrence