Little fixes to facilitate the sharr evaluation

[jmafoster1]

Main changes

hill_climber_discovery.py

• Normalising fitness by number of generated tests
• Using a for loop for generational process instead of a while

'causal_dag.py`

• Override add_edges_from to include a check for cycles
• Removed resulting dead code cycle check from constructor

__main__.py
Outputting raw discovered DAG rather than a pretty rendering of passing/failing test results.

Tests for the above.

[github-actions]

🦙 MegaLinter status: ⚠️ WARNING

Descriptor	Linter	Files	Fixed	Errors	Elapsed time
⚠️ PYTHON	black	30		1	1.05s
✅ PYTHON	pylint	30		0	5.7s

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[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 98.48%. Comparing base (e753b1e) to head (63084f6).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #405      +/-   ##
==========================================
- Coverage   98.54%   98.48%   -0.07%     
==========================================
  Files          25       25              
  Lines        1514     1517       +3     
==========================================
+ Hits         1492     1494       +2     
- Misses         22       23       +1     

Files with missing lines	Coverage Δ
causal_testing/__main__.py	99.16% <100.00%> (+<0.01%)	⬆️
causal_testing/causal_testing_framework.py	100.00% <100.00%> (ø)
causal_testing/discovery/hill_climber_discovery.py	100.00% <100.00%> (ø)
causal_testing/discovery/nsga_discovery.py	100.00% <100.00%> (ø)
causal_testing/specification/causal_dag.py	99.56% <100.00%> (+<0.01%)	⬆️

... and 1 file with indirect coverage changes

---

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[jmafoster1]

Looking at the codecov report, there's not actually anything missing, it's just that the codebase has got slightly smaller.

[jwhogg]

lgtm