"""
Module with tests for the RegexRemovePreprocessor.
"""

# Copyright (c) IPython Development Team.
# Distributed under the terms of the Modified BSD License.

import re
from nbformat import v4 as nbformat

from .base import PreprocessorTestsBase
from ..regexremove import RegexRemovePreprocessor


class TestRegexRemove(PreprocessorTestsBase):
    """Contains test functions for regexremove.py"""

    def build_notebook(self):
        notebook = super(TestRegexRemove, self).build_notebook()
        # Add a few empty cells
        notebook.cells.extend([
            nbformat.new_code_cell(''),
            nbformat.new_markdown_cell(' '),
            nbformat.new_raw_cell('\n'),
            nbformat.new_raw_cell('\t'),
        ])

        return notebook

    def build_preprocessor(self):
        """Make an instance of a preprocessor"""
        preprocessor = RegexRemovePreprocessor()
        preprocessor.enabled = True
        return preprocessor

    def test_constructor(self):
        """Can a RegexRemovePreprocessor be constructed?"""
        self.build_preprocessor()

    def test_output(self):
        """Test the output of the RegexRemovePreprocessor"""
        pattern_lookup = {
            'disallow_whitespace': [r'\s*\Z'],
            'disallow_tab_newline': [r'\t\Z', r'\n\Z']
        }
        expected_cell_count = {
            'default': 5,  # only strictly empty cells
            'disallow_whitespace': 2,  # all "empty" cells are removed
            'disallow_tab_newline': 3, # all "empty" cells but the single space
            'none': 6,
        }
        for method in ['default', 'disallow_whitespace', 'disallow_tab_newline', 'none']:
            nb = self.build_notebook()
            res = self.build_resources()

            # Build the preprocessor and extend the list of patterns or use an empty list
            preprocessor = self.build_preprocessor()
            if method == 'none':
                preprocessor.patterns = []
            else:
                preprocessor.patterns.extend(pattern_lookup.get(method, []))
            nb, res = preprocessor(nb, res)

            self.assertEqual(len(nb.cells), expected_cell_count[method])

            # Make sure none of the cells match the pattern
            patterns = list(map(re.compile, preprocessor.patterns))
            for cell in nb.cells:
                for pattern in patterns:
                    self.assertFalse(pattern.match(cell.source))
