Per cell exception

[mpacer]

Closes #680.

[takluyver]

This docstring doesn't seem quite right.

[mpacer]

agreed.

[takluyver]

It feels a bit clumsy to be adding another boolean config option which overrides an existing one, but I don't have a better idea right now.

The help string could be improved, however. "It does nothing" only makes sense if you know what the default behaviour is. I'd suggest something like:

If False (default), errors from executing the notebook can be allowed with a raises-exception tag on a single cell, or the allow_errors configurable option for all cells. An allowed error will be recorded in notebook output, and execution will continue. If an error occurs when it is not allowed, CellExecutionError will be raised.
If True, CellExecutionError will be raised for any error executing the notebook. This overrides both the allow_errors option and the raises-exception cell tag.

[takluyver]

This one is actually testing force_raise_errors, though.

Can we split this into two tests: one with this name and docstring, and another one with this code (test_force_raise_errors)? ;-)

[mpacer]

Technically the test of it on its own implicitly occurs earlier in the global "convert everything!" test:

nbconvert/nbconvert/preprocessors/tests/test_execute.py

Lines 122 to 137 in 0a262a3

	def test_run_notebooks(self):
	"""Runs a series of test notebooks and compares them to their actual output"""
	input_files = glob.glob(os.path.join(current_dir, 'files', '*.ipynb'))
	for filename in input_files:
	if os.path.basename(filename) == "Disable Stdin.ipynb":
	continue
	elif os.path.basename(filename) == "Interrupt.ipynb":
	opts = dict(timeout=1, interrupt_on_timeout=True, allow_errors=True)
	elif os.path.basename(filename) == "Skip Exceptions.ipynb":
	opts = dict(allow_errors=True)
	else:
	opts = dict()
	res = self.build_resources()
	res['metadata']['path'] = os.path.dirname(filename)
	input_nb, output_nb = self.run_notebook(filename, opts, res)
	self.assert_notebooks_equal(input_nb, output_nb)

But you're right that this should explicitly test force_raise_errors instead

[takluyver]

Aha, great. In that case, if you just want to fix the test name and docstring, I think this is ready to go.