* Adds tests for the "blockAtDepth" function and verify old other tests.
* Optimization on create the Dag chain.
* Changes according to the review - more detailed error messages, added constants, changed to 3 independent graphs (instead of extending), and changes all the abbreviations.
* Changes according to the review - divide the test into three separate tests and change names to variables.
* Changes according to the review - the order of the function has changed.
* delete double lines
Co-authored-by: tal <tal@daglabs.com>
Co-authored-by: Svarog <feanorr@gmail.com>
