Setup markdown object.

Slugify a string, to make it URL friendly while preserving Unicode characters.

Override default to handle any `etree` elements still in the stash.

Extract raw HTML from stash, reduce to plain text and swap with placeholder.

Store tag data and return a placeholder.

Test for block type. Must be overridden by subclasses. As the parser loops through processors, it will call the `test` method on eac

Ensure first two rows (column header and separator row) are valid table rows. Keep border check and separator row do avoid repeating

Test that appended escapes are only in the current instance.

Test failure on bad output_format.

Test serialization of `QName` with no tag.

Test that the base Extension class will raise `NotImplemented`.

Test basic metadata.

Test `[[wikilinks]]`.

Test blank input.

Test State when empty.

Test that appended escapes are only in the current instance.

Test that last `<br>` in tree has a new line tail

Test that an `ElementTree` `Comment` is recognized as `BlockLevel`.

Test that an `ElementTree` `Comment` passes the `is Comment` test.

Test that an `ElementTree` `Comment` is prettified properly.

Test that an `ElementTree` `Comment` serializes properly.

Test Complex Settings.

Test Extension loading with Name (`path.to.module`).

Test Extension loading with non-existent class name (`path.to.module:Class`).

Test Extension loading with class name (`path.to.module:Class`).

Test Extension loading with an entry point.