Adding string={pearson, spearman} option to increasing argument in IsotonicRegression.
Adding increasing and decreasing tests for both Pearson and Spearman increasing argument options
Refactoring increasing_bool set into _check_increasing method
PEP8ing isotonic tests
PEPing isotonic regression
Docstring style changes
Change arguments to increasing={'auto', True, False} and default to 'auto'; implement Fisher transform and warning on 0 \in CI
Adding test for CI check and removing Spearman/Pearson-specific tests.
Minor docstring cleanup
Minor docstring cleanup
Docstring fix
Replacing the non-test .todense() methods with .toarray()
Replacing the test .todense() methods with .toarray()
Improving tests to affirm no CI warnings are thrown when appropriate
Matching CI calculation and docstring with reference
Fixing docstring
Refactoring check_increasing, ensuring that increasing_ is only set on fit/fit_transform, and fixing rho \in {-1, +1}
Reorganizing tests to isolate check_increasing from increasing='auto'
Fixing redundant np.asarray(X.toarray()) in metrics
Improving tests based on feedback from @GaelVaroquaux