ansible/test/integration/targets/blockinfile/tasks/preserve_line_endings.yml

- name: create line_endings_test.txt in the test dir
  copy:
    dest: "{{ remote_tmp_dir_test }}/line_endings_test.txt"
    # generating the content like this instead of copying a fixture file
    # prevents sanity checks from warning about mixed line endings
    content: "unix\nunix\nunix\n\ndos\r\ndos\r\ndos\r\n\nunix\nunix\n# BEGIN ANSIBLE MANAGED BLOCK\ndos\r\n# END ANSIBLE MANAGED BLOCK\nunix\nunix\nunix\nunix\n"

- name: insert/update "dos" configuration block in line_endings_test.txt
  blockinfile:
    path: "{{ remote_tmp_dir_test }}/line_endings_test.txt"
    block: "dos\r\ndos\r\ndos\r\n"
  register: blockinfile_test2

- name: check content
  # using the more precise `grep -Pc "^dos\\r$" ...` fails on BSD/macOS
  shell: 'grep -c "^dos.$" {{ remote_tmp_dir_test }}/line_endings_test.txt'
  register: blockinfile_test2_grep

- name: validate line_endings_test.txt results
  assert:
    that:
      - 'blockinfile_test2 is changed'
      - 'blockinfile_test2.msg == "Block inserted"'
      - 'blockinfile_test2_grep.stdout == "6"'