My focus earlier on had been on relationship to `main` branch
so this is to ensure that we have some tests that cover
relationship between a pair of branches that doesn't
include `main`.
In these tests, a new branch is created but then a commit is made
on the main branch before the new branch gets a commit. This
important to see what happens with rerouting of arrows.
Suggested by @nirname in PR review of #4927.
Followed practice of other tests so that commit IDs are
stabilised (i.e., not randomly generated) and therefore
don't show repeatedly in Cypress diff output screenshots
Add a commit id to 'should render a simple gitgraph with a title',
as otherwise the gitgraph renderer picks a random commit ID, and so
image snapshots will be different.
gitGraph render tests are currently using random commit ids,
which causes visual regression tests to fail.
I couldn't find a way to make the random commit IDs consistent
(JavaScript/Cypress doesn't seem to have a random.seed() function),
so I've just hardcoded all the commit ids.
Currently, merge commits can have a git tag, but they cannot have a
custom git commit ID.
This commit allows modifying the default merge commit id.
It also displays all merge commits IDs, which undoes
3ccf027f42
