Before:
  source ../after/ftplugin/markdown.vim

After:
  setlocal foldexpr=0
  setlocal foldmethod=manual

Given markdown;
# Title

## Chapter 1

```
This is code block
# This is just a comment
```

## Capter 2

foobar

Execute (fold level # in code block):
  AssertEqual foldlevel(1), 0, '# Title'
  AssertEqual foldlevel(3), 1, '## Chapter 1'
  AssertEqual foldlevel(7), 2, '# This is just a comment'
  AssertEqual foldlevel(8), 2, '```'
  AssertEqual foldlevel(10), 1, '## Chapter 2'
  AssertEqual foldlevel(12), 2, 'foobar'

Given markdown;
Fold Level 1
============
Fold Level 2
------------

Execute (fold level ==, --):
  AssertEqual foldlevel(2), 1, '=='
  AssertEqual foldlevel(4), 2, '--'

Given markdown;
# H1

## H1.1

## H1.2

# H2

Execute (fold level # in last line):
  AssertEqual foldlevel(1), 0, '# H1'
  AssertEqual foldlevel(3), 1, '## H1.1'
  AssertEqual foldlevel(5), 1, '## H1.2'
  AssertEqual foldlevel(7), 0, '# H2'