pytest2md 190423

Create and run markdown Readmes from within pytest

---

author: gk version: 190423

---

Generating Markdown - While Testing Contained Claims

Table Of Contents

• Inline Python Function Execution
• Tools
• Files
• Link Replacements
  • Spec
  • Code Repo Hoster Specific Source Links
    • Setting a link template
    • Link Refs
  • Summary
• Isolation

Few things are more annoying than stuff which does not work as announced, especially when you find out only after an invest of time and energy.

Documentation is often prone to produce such situations, since hard to keep 100% in sync with the code evolution.

This is a set of tools, generating documentation, while verifying the documented claims about code behaviour - without the need to adapt the source code, e.g. by modifying doc strings:

When the documentation is using a lot of code examples then a very welcome additional benefit of writing it like shown is the availability of source code autoformatters.

Other Example:

This "README.md" was built into this template, where [title:html comment style placeholders,fmatch:README.tmpl.md,show_raw:True] had been replaced while running pytest on this testfile:

"""
Creates Readme - while testing functions of p2m.


While pytest is running we simply assemble from scratch an intermediate .md file
in append only mode, located within the tests folder.
This we insert between two seperators in the target markdown file, as the last
test function, done.
"""
import pytest2md as p2m
import pytest, json, os, time
from functools import partial
from uuid import uuid4
import json

# a P2M instance contains all we need:
p2m = p2m.P2M(__file__, fn_target_md='README.md')

# py2.7 compat:


# parametrizing the shell run results:
run = partial(p2m.bash_run, no_cmd_path=True)


class TestChapter1:
    def test_one(self):
        t = """

        This is a set of tools, *generating* documentation, while verifying the documented
        claims about code behaviour - without the need to adapt the source code, e.g. by modifying
        doc strings:

        ![](./assets/shot1.png)

        > When the documentation is using a lot of code examples then a very welcome
        additional benefit of writing it like shown is the availability of [source
        code autoformatters](https://github.com/ambv/black).

        Other Example:

        This "README.md" was built into [this](./README.tmpl.md) template,
        where [title:html comment style placeholders,fmatch:README.tmpl.md,show_raw:True]<SRC>
        had been replaced while running pytest on this testfile:

        <from_file: %s>

        """ % (
            __file__,
        )

        p2m.md(t)
        p2m.md(
            """
        Lets run a bash command and assert on its results.
        Note that the command is shown in the readme, incl. result and the result
        can be asserted upon.
        """
        )

        res = run('cat "/etc/hosts" | grep localhost')
        assert '127.0.0.1' in res[0]['res']

    def test_two(self):
        res = run(['ls "%(d_test)s"' % p2m.ctx, 'ls -lta /etc/hosts'])
        assert 'tutorial' in res[0]['res']
        assert 'hosts' in res[1]['res']

    def test_simple_pyfuncs(self):
        """
        # Inline Python Function Execution

        via the `md_from_source_code` function you can write fluent markdown
        (tested) python combos:
        """

        def foo():
            hi = 'hello world'
            assert 'world' in hi
            print(hi.replace('world', 'joe'))

        """
        The functions are evaluated and documented in the order they show up
        within the textblocks.

        > Please keep tripple apostrophes - we split the text blocks,
        searching for those.

        State is kept within the outer pytest function, like normally in python.
        I.e. if you require new state, then start a new pytest function.

        Stdout is redirected to an output collector function, i.e. if you print
        this does result in an "Output" block. If the printout starts with
        "MARKDOWN:" then we won't wrap that output into fenced code blocks but
        display as is.

        > If the string 'breakpoint' occurs in a function body, we won't redirect
        standardout for displaying output.

        # Tools

        Also there are few tools available, e.g this one:

        """

        def mdtable():
            ht = p2m.html_table

            t = ht(
                [['joe', 'doe'], ['suzie', 'wong']],
                ['first', 'last'],
                summary='names. click to open...',
            )
            assert 'details' in t
            assert 'joe</td' in t
            print(t)

        """
        Another tool is the simple TOC generator, invoked like at the end of this file.
        """

        p2m.md_from_source_code()

    def test_file_create_show(self):
        p2m.md(
            """
        # Files
        When working with files, the `sh_file` function is helpful,
        producing output like this one:"""
        )
        ts = time.ctime()
        c = json.dumps({'a': [{'testfile': 'created'}, 'at', ts]}, indent=4)
        # if content is given it will create it:
        fn = '/tmp/' + str(uuid4())
        p2m.sh_file(fn, lang='javascript', content=c)

        # check existance:
        with open(fn) as fd:
            assert fd.read() == c
        os.unlink(fn)

    def test_mdtool(self):
        md = """
        # Link Replacements

        Technical markdown content wants to link to source code often.
        How to get those links working and that convenient?

        The module does offer also some source finding / link replacement feature,
        via the [mdtool]<SRC> module. The latter link was built simply by this:

        ```
        [mdtool]<SRC>
        ```


        Other example: This [pytest2md]<SRC> link was created by replacing "SRC" with the path
        to a file matching, under a given directory, prefixed by an arbitrary base URL.

        ## Spec

        These will be replaced:

        `[title:this,fmatch:test_tutorial,lmatch:exotic] <SRC>` (remove space between] and <)

        - title: The link title - text the user reads
        - fmatch: substring match for the link destination file
        - lmatch: Find matching line within that file
        - show_raw: Link to raw version of file, not the one rendered by the
          repo server
        - path: Fix file path (usually derived by fmach)
        - line: Fix the line number of the link (usually done via lmatch)

        ## Code Repo Hoster Specific Source Links

        Github, Gitlab, Bitbucked or Plain directory based static content servers
        all have their conventional URLs regarding those links.

        Since all of these are just serving static content w/o js possibilities,
        you have to parametrize the intended hoster in your environment, before
        running a pytest / push cycle. That way the links will be working on the hoster.

        Currently we understand the following namespaces for links:


        ```javascript
        _link_names_
        ```

        ### Setting a link template

        - `export MD_LINKS_FOR=github   ` # before running pytest / push
        - `<!-- md_links_for: github -->` # in the markdown template, static

        The latter can be overwritten by environ, should you want to push from time to time
        to a different code hoster.

        ### Link Refs

        We minimize the problem of varying generated target markdown, dependent on the hoster.
        How? Like [any problem in IT is solved](https://en.wikipedia.org/wiki/Fundamental_theorem_of_software_engineering).


        By building [reference links](https://github.com/adam-p/markdown-here/wiki/Markdown-Cheatsheet#links)
        the differences of e.g. a README.md for github vs. gitlab is
        restricted to the links section on the end of the generated markdown.
        In the markdown bodies you'll just see link names, which remain the same.

        > Check the end of the [title:rendering result,fmatch:README.md,show_raw:True]<SRC> at the end of this README.md,
        in order to see the results for the hoster you are reading this markdown file currently.

        ## Summary

        - At normal runs of pytest, the link base URL is just a local `file://` link,

        - Before pushes one can set via environ (e.g. `export
          MD_LINKS_FOR=github`)  these e.g. to the github base URL or the repo.

        - `[key-values]` constructs are supported as well, extending to beyond
          just the base url. Example following:

        """.replace(
            '_link_names_',
            json.dumps(p2m.src_link_templates, indent=4, sort_keys=2),
        )
        p2m.md(md)

    def test_sh_code(self):
        p2m.md('Source code showing is done like this:')
        p2m.sh_code(self.test_sh_code)
        p2m.md(
            '> Is [title:this,fmatch:test_tutorial,lmatch:exotic]<SRC> an exotic form of a recursion? ;-)  '
        )

    def test_write(self):
        """has to be the last 'test'"""
        # default is ../README.md
        p2m.write_markdown(with_source_ref=True, make_toc=True)

Lets run a bash command and assert on its results. Note that the command is shown in the readme, incl. result and the result can be asserted upon.

$ cat "/etc/hosts" | grep localhost
# localhost is used to configure the loopback interface
127.0.0.1  localhost lo sd1 sd3 sa1 sa2 sb1 sb2
::1             localhost

$ ls "/Users/gk/GitHub/pytest2md/tests"
__pycache__
test_basics.py
test_changelog.py
test_tutorial.py

$ ls -lta /etc/hosts
-rw-r--r--  1 root  wheel  1047 Mar  1 11:35 /etc/hosts

Inline Python Function Execution

via the md_from_source_code function you can write fluent markdown (tested) python combos:

hi = 'hello world'
assert 'world' in hi
print(hi.replace('world', 'joe'))

Output:

hello joe

The functions are evaluated and documented in the order they show up within the textblocks.

Please keep tripple apostrophes - we split the text blocks, searching for those.

State is kept within the outer pytest function, like normally in python. I.e. if you require new state, then start a new pytest function.

Stdout is redirected to an output collector function, i.e. if you print this does result in an "Output" block. If the printout starts with "MARKDOWN:" then we won't wrap that output into fenced code blocks but display as is.

If the string 'breakpoint' occurs in a function body, we won't redirect standardout for displaying output.

Tools

Also there are few tools available, e.g this one:

ht = p2m.html_table

t = ht(
    [['joe', 'doe'], ['suzie', 'wong']],
    ['first', 'last'],
    summary='names. click to open...',
)
assert 'details' in t
assert 'joe</td' in t
print(t)

names. click to open...

first	last
joe	doe
suzie	wong

Another tool is the simple TOC generator, invoked like at the end of this file.

Files

When working with files, the sh_file function is helpful, producing output like this one:

$ cat "1f85660c-6959-4e38-bda2-3cbff6159bd2"
{
    "a": [
        {
            "testfile": "created"
        },
        "at",
        "Mon Apr 22 11:00:37 2019"
    ]
}

Link Replacements

Technical markdown content wants to link to source code often. How to get those links working and that convenient?

The module does offer also some source finding / link replacement feature, via the [mdtool] module. The latter link was built simply by this:

[mdtool]<SRC>

Other example: This [pytest2md] link was created by replacing "SRC" with the path to a file matching, under a given directory, prefixed by an arbitrary base URL.

Spec

These will be replaced:

[title:this,fmatch:test_tutorial,lmatch:exotic] <SRC> (remove space between] and <)

• title: The link title - text the user reads
• fmatch: substring match for the link destination file
• lmatch: Find matching line within that file
• show_raw: Link to raw version of file, not the one rendered by the repo server
• path: Fix file path (usually derived by fmach)
• line: Fix the line number of the link (usually done via lmatch)

Code Repo Hoster Specific Source Links

Github, Gitlab, Bitbucked or Plain directory based static content servers all have their conventional URLs regarding those links.

Since all of these are just serving static content w/o js possibilities, you have to parametrize the intended hoster in your environment, before running a pytest / push cycle. That way the links will be working on the hoster.

Currently we understand the following namespaces for links:

{
    "github": "https://github.com/%(gh_repo_name)s/blob/%(git_rev)s/%(path)s%(line:#L%s)s",
    "github_raw": "https://raw.githubusercontent.com/%(gh_repo_name)s/%(git_rev)s/%(path)s%(line:#L%s)s",
    "static": "file://%(d_repo_base)s/%(path)s",
    "static_raw": "file://%(d_repo_base)s/%(path)s"
}

Setting a link template

• export MD_LINKS_FOR=github # before running pytest / push
• <!-- md_links_for: github --> # in the markdown template, static

The latter can be overwritten by environ, should you want to push from time to time to a different code hoster.

Link Refs

We minimize the problem of varying generated target markdown, dependent on the hoster. How? Like any problem in IT is solved.

By building reference links the differences of e.g. a README.md for github vs. gitlab is restricted to the links section on the end of the generated markdown. In the markdown bodies you'll just see link names, which remain the same.

Check the end of the [title:rendering result,fmatch:README.md,show_raw:True] at the end of this README.md, in order to see the results for the hoster you are reading this markdown file currently.

Summary

• At normal runs of pytest, the link base URL is just a local file:// link,

• Before pushes one can set via environ (e.g. export MD_LINKS_FOR=github) these e.g. to the github base URL or the repo.

• [key-values] constructs are supported as well, extending to beyond just the base url. Example following:

Source code showing is done like this:

    def test_sh_code(self):
        p2m.md('Source code showing is done like this:')
        p2m.sh_code(self.test_sh_code)
        p2m.md(
            '> Is [title:this,fmatch:test_tutorial,lmatch:exotic]<SRC> an exotic form of a recursion? ;-)  '
        )

Is [title:this,fmatch:test_tutorial,lmatch:exotic] an exotic form of a recursion? ;-)

Auto generated by pytest2md, running test_tutorial.py

Isolation

None. If you would screw up your host running pytest normally, then you will get the same result, when running markdown generating tests.

Here is a bigger tutorial, created from pytest2md. There you'll learn in addition to shell runners how to generate markdown from running inline python functions...