scprep slingshot tests are failing

[scottgigante-immunai]

Describe the bug
test_slingshot fails, preventing all PRs from passing

To Reproduce

cd scprep
pytest -v

Expected behavior
Passes.

Actual behavior
Fails.

======================================================================
ERROR: test_slingshot (test_run.TestSlingshot)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/runner/work/scprep/scprep/test/test_run.py", line 446, in test_slingshot
    self.X_pca[:, :2], self.clusters, verbose=False
  File "/home/runner/work/scprep/scprep/scprep/run/slingshot.py", line 258, in Slingshot
    rpy_verbose=verbose,
  File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/decorator.py", line 232, in fun
    return caller(func, *(extras + args), **kw)
  File "/home/runner/work/scprep/scprep/scprep/utils.py", line 80, in _with_pkg
    return fun(*args, **kwargs)
  File "/home/runner/work/scprep/scprep/scprep/run/r_function.py", line 124, in __call__
    robject = self.function(*args, **kwargs)
  File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/rpy2/robjects/functions.py", line 199, in __call__
    .__call__(*args, **kwargs))
  File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/rpy2/robjects/functions.py", line 125, in __call__
    res = super(Function, self).__call__(*new_args, **new_kwargs)
  File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/rpy2/rinterface_lib/conversion.py", line 45, in _
    cdata = function(*args, **kwargs)
  File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/rpy2/rinterface.py", line 680, in __call__
    raise embedded.RRuntimeError(_rinterface._geterrmessage())
rpy2.rinterface_lib.embedded.RRuntimeError: Error in if (is.na(as.numeric(omega))) { : argument is of length zero


======================================================================
ERROR: test_slingshot_errors (test_run.TestSlingshot)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/runner/work/scprep/scprep/test/test_run.py", line 564, in test_slingshot_errors
    verbose=False,
  File "/home/runner/work/scprep/scprep/test/tools/utils.py", line 20, in assert_warns_message
    return assert_warns_regex(expected_warning, expected_regex, *args, **kwargs)
  File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/unittest/case.py", line 1317, in assertWarnsRegex
    return context.handle('assertWarnsRegex', args, kwargs)
  File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/unittest/case.py", line 178, in handle
    callable_obj(*args, **kwargs)
  File "/home/runner/work/scprep/scprep/scprep/run/slingshot.py", line 258, in Slingshot
    rpy_verbose=verbose,
  File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/decorator.py", line 232, in fun
    return caller(func, *(extras + args), **kw)
  File "/home/runner/work/scprep/scprep/scprep/utils.py", line 80, in _with_pkg
    return fun(*args, **kwargs)
  File "/home/runner/work/scprep/scprep/scprep/run/r_function.py", line 124, in __call__
    robject = self.function(*args, **kwargs)
  File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/rpy2/robjects/functions.py", line 199, in __call__
    .__call__(*args, **kwargs))
  File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/rpy2/robjects/functions.py", line 125, in __call__
    res = super(Function, self).__call__(*new_args, **new_kwargs)
  File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/rpy2/rinterface_lib/conversion.py", line 45, in _
    cdata = function(*args, **kwargs)
  File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/rpy2/rinterface.py", line 680, in __call__
    raise embedded.RRuntimeError(_rinterface._geterrmessage())
rpy2.rinterface_lib.embedded.RRuntimeError: Error in if (is.na(as.numeric(omega))) { : argument is of length zero


======================================================================
ERROR: test_slingshot_optional_args (test_run.TestSlingshot)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/runner/work/scprep/scprep/test/test_run.py", line 513, in test_slingshot_optional_args
    verbose=False,
  File "/home/runner/work/scprep/scprep/scprep/run/slingshot.py", line 258, in Slingshot
    rpy_verbose=verbose,
  File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/decorator.py", line 232, in fun
    return caller(func, *(extras + args), **kw)
  File "/home/runner/work/scprep/scprep/scprep/utils.py", line 80, in _with_pkg
    return fun(*args, **kwargs)
  File "/home/runner/work/scprep/scprep/scprep/run/r_function.py", line 124, in __call__
    robject = self.function(*args, **kwargs)
  File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/rpy2/robjects/functions.py", line 199, in __call__
    .__call__(*args, **kwargs))
  File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/rpy2/robjects/functions.py", line 125, in __call__
    res = super(Function, self).__call__(*new_args, **new_kwargs)
  File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/rpy2/rinterface_lib/conversion.py", line 45, in _
    cdata = function(*args, **kwargs)
  File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/rpy2/rinterface.py", line 680, in __call__
    raise embedded.RRuntimeError(_rinterface._geterrmessage())
rpy2.rinterface_lib.embedded.RRuntimeError: Error in h(simpleError(msg, call)) : 
  error in evaluating the argument 'X' in selecting a method for function 'lapply': no slot of name "curves" for this object of class "PseudotimeOrdering"


======================================================================
ERROR: test_slingshot_pandas (test_run.TestSlingshot)
----------------------------------------------------------------------
Traceback (most recent call last):
  File "/home/runner/work/scprep/scprep/test/test_run.py", line 471, in test_slingshot_pandas
    verbose=False,
  File "/home/runner/work/scprep/scprep/scprep/run/slingshot.py", line 258, in Slingshot
    rpy_verbose=verbose,
  File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/decorator.py", line 232, in fun
    return caller(func, *(extras + args), **kw)
  File "/home/runner/work/scprep/scprep/scprep/utils.py", line 80, in _with_pkg
    return fun(*args, **kwargs)
  File "/home/runner/work/scprep/scprep/scprep/run/r_function.py", line 124, in __call__
    robject = self.function(*args, **kwargs)
  File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/rpy2/robjects/functions.py", line 199, in __call__
    .__call__(*args, **kwargs))
  File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/rpy2/robjects/functions.py", line 125, in __call__
    res = super(Function, self).__call__(*new_args, **new_kwargs)
  File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/rpy2/rinterface_lib/conversion.py", line 45, in _
    cdata = function(*args, **kwargs)
  File "/opt/hostedtoolcache/Python/3.7.12/x64/lib/python3.7/site-packages/rpy2/rinterface.py", line 680, in __call__
    raise embedded.RRuntimeError(_rinterface._geterrmessage())
rpy2.rinterface_lib.embedded.RRuntimeError: Error in if (is.na(as.numeric(omega))) { : argument is of length zero

scprep version
master