How to use the jupytext.compare.compare_notebooks function in jupytext

def test_notebook_metadata_differ():
    nb1 = new_notebook(cells=[new_code_cell('1'),
                              new_code_cell('2')])
    nb2 = new_notebook(cells=[new_code_cell('1'),
                              new_code_cell('2')],
                       metadata={'kernelspec': {'language': 'python', 'name': 'python', 'display_name': 'Python'}})
    with pytest.raises(NotebookDifference) as exception_info:
        compare_notebooks(nb2, nb1, raise_on_first_difference=False)
    assert "Notebook metadata differ" in exception_info.value.args[0]

def test_two_markdown_cell_with_code_works(nb=new_notebook(cells=[
    new_markdown_cell("""```python
1 + 1
```"""),
    new_markdown_cell("""```python
2 + 2
```""")
])):
    text = jupytext.writes(nb, 'md')
    nb2 = jupytext.reads(text, 'md')
    compare_notebooks(nb2, nb)

compare_notebooks(read(tmp_py), nb)

    assert os.path.isfile(tmp_rmd)
    compare_notebooks(read(tmp_rmd), nb, 'Rmd')

    write(nb, tmp_rmd, 'Rmd')
    jupytext(['--sync', tmp_ipynb])

    nb2 = read(tmp_ipynb)
    compare_notebooks(nb2, nb, 'Rmd', compare_outputs=True)

    write(nb, tmp_py, 'py')
    jupytext(['--sync', tmp_ipynb])

    nb2 = read(tmp_ipynb)
    compare_notebooks(nb2, nb, compare_outputs=True)

    # Finally we recreate the ipynb
    os.remove(tmp_ipynb)

    time.sleep(0.1)
    jupytext(['--sync', tmp_py])

    nb2 = read(tmp_ipynb)
    compare_notebooks(nb2, nb)

    # ipynb must be older than py file, otherwise our Contents Manager will complain
    assert os.path.getmtime(tmp_ipynb) <= os.path.getmtime(tmp_py)

cm.root_dir = str(tmpdir)

    # save notebook
    cm.save(model=dict(type='notebook', content=nb), path=tmp_ipynb)

    # check that text representation exists, and is in percent format
    with open(str(tmpdir.join(tmp_script))) as stream:
        assert read_format_from_metadata(stream.read(), auto_ext) == 'percent'

    # reload and compare with original notebook
    model = cm.get(path=tmp_script)

    # saving should not create a format entry #95
    assert 'formats' not in model['content'].metadata.get('jupytext', {})

    compare_notebooks(model['content'], nb)

def test_identity_source_write_read(nb_file, ext):
    """
    Test that writing the notebook with R, and read again,
    is the same as removing outputs
    """

    with open(nb_file) as fp:
        nb1 = nbformat.read(fp, as_version=4)

    R = jupytext.writes(nb1, ext)
    nb2 = jupytext.reads(R, ext)

    compare_notebooks(nb2, nb1)

model = cm.get(tmp_nbpy)

    # Check that format is explicit
    assert model['content']['metadata']['jupytext']['formats'] == 'ipynb,py:light'

    # Check contents
    compare_notebooks(model['content'], nb)

    # Change save format and save
    model['content']['metadata']['jupytext']['formats'] == 'ipynb,py'
    cm.preferred_jupytext_formats_save = 'py:percent'
    cm.save(model=dict(type='notebook', content=nb), path=tmp_ipynb)

    # Read notebook
    model = cm.get(tmp_nbpy)
    compare_notebooks(model['content'], nb)

    # Check that format is explicit
    assert model['content']['metadata']['jupytext']['formats'] == 'ipynb,py:percent'

compare_notebooks(nb2, nb, 'Rmd', compare_outputs=True)

    write(nb, tmp_py, 'py')
    jupytext(['--sync', tmp_ipynb])

    nb2 = read(tmp_ipynb)
    compare_notebooks(nb2, nb, compare_outputs=True)

    # Finally we recreate the ipynb
    os.remove(tmp_ipynb)

    time.sleep(0.1)
    jupytext(['--sync', tmp_py])

    nb2 = read(tmp_ipynb)
    compare_notebooks(nb2, nb)

    # ipynb must be older than py file, otherwise our Contents Manager will complain
    assert os.path.getmtime(tmp_ipynb) <= os.path.getmtime(tmp_py)

def test_read_file_with_explicit_fmt(tmpdir):
    tmp_py = str(tmpdir.join('notebook.py'))

    with open(tmp_py, 'w') as fp:
        fp.write("""# %%
1 + 1
""")

    nb1 = jupytext.read(tmp_py)
    nb2 = jupytext.read(tmp_py, fmt='py:percent')

    compare_notebooks(nb2, nb1)

def test_raise_on_different_cell_content(raise_on_first_difference):
    ref = new_notebook(cells=[new_markdown_cell('Cell one'), new_code_cell('Cell two')])
    test = new_notebook(cells=[new_markdown_cell('Cell one'), new_code_cell('Modified cell two')])
    with pytest.raises(NotebookDifference):
        compare_notebooks(test, ref, 'md', raise_on_first_difference=raise_on_first_difference)

def test_two_markdown_cell_with_no_language_code_works(nb=new_notebook(cells=[
    new_markdown_cell("""```
1 + 1
```"""),
    new_markdown_cell("""```
2 + 2
```""")
])):
    text = jupytext.writes(nb, 'md')
    nb2 = jupytext.reads(text, 'md')
    compare_notebooks(nb2, nb)