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phmdoctest

Python syntax highlighted Markdown doctest.

phmdoctest 1.4.0

Introduction

Python syntax highlighted Markdown doctest

Command line program and Python library to test Python syntax highlighted code examples in Markdown.

default branch status

Code style: black

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Website | Docs | Repos | pytest | Codecov | License

Introduction | Installation | Sample usage | Sample Usage with HTML comment directives | CI usage | –report | Identifying blocks | Directives | skip | label on code and sessions | label on any fenced code block | pytest skip | pytest skipif | setup | teardown | share-names | clear-names | pytest mark decorator | label skip and mark example | setup and teardown example | share-names clear-names example | Configuration | Inline annotations | skipping blocks with –skip | –skip | short form of –skip | –fail-nocode | –setup | –teardown | Setup example | Setup for sessions | Execution context | Send outfile to stdout | Usage | Run as a Python module | Python API | pytest fixtures | Simulate command line | Hints | Directive hints | Related projects

Changes | Contributions | About

Installation

It is advisable to install in a virtual environment.

python -m pip install phmdoctest

Sample usage

Given the Markdown file example1.md shown in raw form here…

# This is Markdown file example1.md

## Interactive Python session (doctest)

```py
>>> print("Hello World!")
Hello World!
```

## Source Code and terminal output

Code:
```python
from enum import Enum

class Floats(Enum):
    APPLES = 1
    CIDER = 2
    CHERRIES = 3
    ADUCK = 4

for floater in Floats:
    print(floater)
```

sample output:
```
Floats.APPLES
Floats.CIDER
Floats.CHERRIES
Floats.ADUCK
```

the command…

phmdoctest doc/example1.md --outfile test_example1.py

creates the python source code file test_example1.py shown here…

"""pytest file built from doc/example1.md"""
from phmdoctest.functions import _phm_compare_exact


def session_00001_line_6():
    r"""
    >>> print("Hello World!")
    Hello World!
    """


def test_code_14_output_28(capsys):
    from enum import Enum

    class Floats(Enum):
        APPLES = 1
        CIDER = 2
        CHERRIES = 3
        ADUCK = 4

    for floater in Floats:
        print(floater)

    _phm_expected_str = """\
Floats.APPLES
Floats.CIDER
Floats.CHERRIES
Floats.ADUCK
"""
    _phm_compare_exact(a=_phm_expected_str, b=capsys.readouterr().out)

Then run a pytest command something like this in your terminal to test the Markdown session, code, and expected output blocks.

pytest --doctest-modules

Or these two commands:

pytest
python -m doctest test_example1.py

The line_6 in the function name session_00001_line_6 is the line number in example1.md of the first line of the interactive session. 00001 is a sequence number to order the doctests.

The 14 in the function name test_code_14_output_28 is the line number of the first line of python code. 28 shows the line number of the expected terminal output.

One test case function gets generated for each:

The --report option below shows the blocks discovered and how they are tested.

Sample Usage with HTML comment directives

Given the Markdown file shown in raw form here…

<!--phmdoctest-mark.skip-->
<!--phmdoctest-label test_example-->
```python
print("Hello World!")
```
```
incorrect expected output
```

the command…

phmdoctest tests/one_mark_skip.md --outfile test_one_mark_skip.py

creates the python source code file shown here…

"""pytest file built from tests/one_mark_skip.md"""
import pytest

from phmdoctest.functions import _phm_compare_exact


@pytest.mark.skip()
def test_example(capsys):
    print("Hello World!")

    _phm_expected_str = """\
incorrect expected output
"""
    _phm_compare_exact(a=_phm_expected_str, b=capsys.readouterr().out)

Run the –outfile with pytest…

$ pytest -vv test_one_mark_skip.py

test_one_mark_skip.py::test_example SKIPPED

CI usage

Test Python examples in README.md in Continuous Integration scripts. In this snippet for Linux the pytest test suite is in the tests folder.

mkdir tests/tmp
phmdoctest README.md --report --outfile tests/tmp/test_readme.py
pytest --doctest-modules -vv tests

This console shows testing Python examples in project.md. Look for the tmp tests at the bottom. Windows Usage on Appveyor.

See this excerpt from ci.yml Actions usage example. It runs on Windows, Linux, and macOS. Please find the phmdoctest command at the bottom.

No changes to README.md are needed here, look in the last job log.

report option

To see the GFM fenced code blocks in the MARKDOWN_FILE use the --report option like this:

phmdoctest doc/example2.md --report

which lists the fenced code blocks it found in the file example2.md. The test role column shows how each fenced code block gets tested.

         doc/example2.md fenced blocks
------------------------------------------------
block     line  test     TEXT or directive
type    number  role     quoted and one per line
------------------------------------------------
python       9  code
            14  output
python      20  code
            26  output
            31  --
python      37  code
python      44  code
            51  output
yaml        59  --
text        67  --
py          75  session
python      87  code
            94  output
py         102  session
------------------------------------------------
7 test cases.
1 code blocks with no output block.

Identifying blocks

The PYPI commonmark project provides code to extract fenced code blocks from Markdown. Specification CommonMark Spec and website CommonMark.

Python code, expected output, and Python interactive sessions get extracted.

Only GFM fenced code blocks are considered.

A block is a session block if the info_string starts with py and the first line of the block starts with the session prompt: '>>> '.

To be treated as Python code the opening fence should start with one of these:

```python
```python3
```py3

plus the block contents can’t start with '>>> '.

The examples use the info_strings python for code and py for sessions since they render with coloring on GitHub, readthedocs, GitHub Pages, and Python package index.

project.md has more examples of code and session blocks.

It is ok if the info string is laden with additional text, it will be ignored. The entire info string will be shown in the block type column of the report.

An output block is a fenced code block that immediately follows a Python block and starts with an opening fence like this which has an empty info string.

```

A Python code block has no output if it is followed by any of:

Test code gets generated for it, but there will be no assertion statement.

Directives

Directives are HTML comments containing test generation commands. They are edited into the Markdown file immediately before a fenced code block. It is OK if other HTML comments are present. See the <!--phmdoctest-skip--> directive in the raw Markdown below. With the skip directive no test code will be generated from the fenced code block.

<!--phmdoctest-skip-->
<!--Another HTML comment-->
```python
print("Hello World!")
```
Expected Output
```
Hello World!
```

List of Directives

       Directive HTML comment      |    Use on blocks
---------------------------------- | ---------------------
<!--phmdoctest-skip-->             | code, session, output
<!--phmdoctest-label IDENTIFIER--> | code, session
<!--phmdoctest-label TEXT-->       | any
<!--phmdoctest-mark.skip-->        | code
<!--phmdoctest-mark.skipif<3.N-->  | code
<!--phmdoctest-setup-->            | code
<!--phmdoctest-teardown-->         | code
<!--phmdoctest-share-names-->      | code
<!--phmdoctest-clear-names-->      | code
<!--phmdoctest-mark.ATTRIBUTE-->   | code

Directive hints

skip

The skip directive or --skip TEXT command line option prevents code generation for the code or session block. The skip directive can be placed on an expected output block. There it prevents checking expected against actual output. Example.

label on code and sessions

When used on a Python code block or session the label directive changes the name of the generated test function. Example. Two generated tests, the first without a label, shown in pytest -v terminal output:

test_readme.py::test_code_93 FAILED
test_readme.py::test_beta_feature FAILED

label on any fenced code block

On any fenced code block, the label directive identifies the block for later retrieval by the class phmdoctest.tool.FCBChooser(). The FCBChooser is used separately from phmdoctest in a different pytest file. This allows the test developer to write additional test cases for fenced code blocks that are not handled by phmdoctest. The directive value can be any string.

# This is file doc/my_markdown_file.md

<!--phmdoctest-label my-fenced-code-block-->
```
The label directive can be placed on any fenced code block.
```

Here is Python code to fetch it:

import phmdoctest.tool

chooser = phmdoctest.tool.FCBChooser("doc/my_markdown_file.md")
contents = chooser.contents(label="my-fenced-code-block")
print(contents)

Output:

The label directive can be placed on any fenced code block.

pytest skip

The <!--phmdoctest-mark.skip--> directive generates a test case with a @pytest.mark.skip() decorator. Example.

pytest skipif

The <!--phmdoctest-mark.skipif<3.N--> directive generates a test case with the pytest decorator @pytest.mark.skipif(sys.version_info < (3, N), reason="requires >=py3.N"). N is a Python minor version number. Example.

setup

A single Python code block can assign names visible to other code blocks by adding a setup directive or using the –setup command line option.

Names assigned by the setup block get copied to the test module’s global namespace after the setup block runs.

Here is an example setup block from setup.md:

import math

mylist = [1, 2, 3]
a, b = 10, 11

def doubler(x):
    return x * 2

Using setup modifies the execution context of the Python code blocks in the Markdown file. The names math, mylist, a, b, and doubler are visible to the other Python code blocks. The objects can be modified. Example.

teardown

Selects a single Python code block that runs at test module teardown time. A teardown block can also be designated using the –teardown command line option. Example.

share-names

Names assigned by the Python code block get copied to the test module as globals after the test code runs. This happens at run time. These names are now visible to subsequent test cases generated for Python code blocks in the Markdown file. share-names modifies the execution context as described for the setup directive above. The share-names directive can be used on more than one code block. Example.

This directive effectively joins its Python code block to the following Python code blocks in the Markdown file.

clear-names

After the test case generated for the Python code block with the clear-names directive runs, all names that were created by one or more preceding share-names directives get deleted. The names that were shared are no longer visible. This directive also deletes the names assigned by setup. Example.

pytest mark decorator

The <!--phmdoctest-mark.ATTRIBUTE--> directive adds a @pytest.mark.ATTRIBUTE decorator to the generated test function. ATTRIBUTE is a valid Python attribute identifier. This defines a marker to pytest that is used to select and deselect tests. See the pytest documentation section “Working with custom markers”. The file mark_example.md contains example usage of the user defined marker “slow”. It generates test_mark_example.py

label skip and mark example

The file directive1.md contains example usage of label, skip, and mark directives. The command below generates test_directive1.py. phmdoctest doc/directive1.md --report produces this report.

phmdoctest doc/directive1.md --outfile test_directive1.py

setup and teardown example

The file directive2.md contains example usage of label, skip, and mark directives. The command below generates test_directive2.py. phmdoctest doc/directive2.md --report produces this report.

phmdoctest doc/directive2.md --outfile test_directive2.py

share-names clear-names example

The file directive3.md contains example usage of share-names and clear-names directives. The command below generates test_directive3.py. phmdoctest doc/directive3.md --report produces this report.

phmdoctest doc/directive3.md --outfile test_directive3.py

Configuration

Supply a .ini, .cfg, or .toml configuration file in place of the Markdown file. Configuration features:

Place a [tool.phmdoctest] section in the configuration file. How to configure.

Inline annotations

Inline annotations comment out sections of code. They can be added to the end of lines in Python code blocks. They should be in a comment.

Here is a snippet showing how to place phmdoctest:pass in the code. The second block shows the code that is generated. Note there is no # immediately before phmdoctest:pass. It is not required.

import time
def takes_too_long():
    time.sleep(100)    # delay for awhile. phmdoctest:pass
takes_too_long()
import time
def takes_too_long():
    pass  # time.sleep(100)    # delay for awhile. phmdoctest:pass
takes_too_long()

Use phmdoctest:omit on single or multi-line statements. Note the two commented out time.sleep(99). They follow and are indented more that the if condition:line with phmdoctest:omit.

import time                      # phmdoctest:omit

condition = True
if condition:       # phmdoctest:omit
    time.sleep(99)
    time.sleep(99)
# import time                      # phmdoctest:omit

condition = True
# if condition:       # phmdoctest:omit
#     time.sleep(99)
#     time.sleep(99)

Inline annotation processing counts the number of commented out sections and adds the count as the suffix _N to the name of the pytest function in the generated test file.

Inline annotations are similar, but less powerful than the Python standard library doctest directive #doctest+SKIP. Improper use of phmdoctest:omit can cause Python syntax errors.

The examples above are snippets that illustrate how to use inline annotations. Here is an example that produces a pytest file from Markdown. The command below takes inline_example.md and generates test_inline_example.py.

phmdoctest doc/inline_example.md --outfile test_inline_example.py

skipping blocks with skip option

If you don’t want to generate test cases for Python blocks precede the block with a skip directive or use the --skip TEXT option. More than one skip directive or--skip TEXTis allowed.

The following describes using --skip TEXT. The code in each Python block gets searched for the substring TEXT. Zero, one or more blocks will contain the substring. These blocks will not generate test cases in the output file.

The report shows which Python blocks get skipped in the test role column, and the Python blocks that matched each –skip TEXT in the skips section.

This option makes it very easy to inadvertently exclude Python blocks from the test cases. In the event no test cases get generated, the option --fail-nocode described below is useful.

Three special --skip TEXT strings work a little differently. They select one of the first, second, or last of the Python blocks. Only Python blocks get counted.

skip option

This command using --skip:

phmdoctest doc/example2.md --skip "Python 3.7" --skip LAST --report --outfile test_example2.py

Produces the report

            doc/example2.md fenced blocks
-----------------------------------------------------
block     line  test          TEXT or directive
type    number  role          quoted and one per line
-----------------------------------------------------
python       9  code
            14  output
python      20  skip-code     "Python 3.7"
            26  skip-output
            31  --
python      37  code
python      44  code
            51  output
yaml        59  --
text        67  --
py          75  session
python      87  code
            94  output
py         102  skip-session  "LAST"
-----------------------------------------------------
5 test cases.
1 skipped code blocks.
1 skipped interactive session blocks.
1 code blocks with no output block.

  skip pattern matches (blank means no match)
------------------------------------------------
skip pattern  matching code block line number(s)
------------------------------------------------
Python 3.7    20
LAST          102
------------------------------------------------

creates the output file test_example2.py

short form of skip option

This is the same command as above using the short -s form of the --skip option in two places. It produces the same report and outfile.

phmdoctest doc/example2.md -s "Python 3.7" -sLAST --report --outfile test_example2.py

fail-nocode option

The --fail-nocode option produces a pytest file that will always fail when no Python code or session blocks get found.

Evem if no Python code or session blocks exist in the Markdown file a pytest file gets generated. This also happens when --skip eliminates all the Python code blocks. The generated pytest file will have the function def test_nothing_passes().

If the option --fail-nocode is passed the function is def test_nothing_fails() which raises an assertion.

setup option

A single Python code block can assign names visible to other code blocks by giving the --setup TEXT option. Please see the setup directive above. The rules for TEXT are the same as for --skip TEXT plus…

teardown option

A single Python code block can supply code run by the pytest teardown_module() fixture. Use the --teardown TEXT option. Please see the teardown directive above. The rules for TEXT are the same as for --setup above except TEXT won’t match a setup block.

Setup example

For the Markdown file setup.md run this command to see how the blocks get tested.

phmdoctest doc/setup.md --setup FIRST --teardown LAST --report
            doc/setup.md fenced blocks
-------------------------------------------------
block     line  test      TEXT or directive
type    number  role      quoted and one per line
-------------------------------------------------
python       9  setup     "FIRST"
python      20  code
            27  output
python      37  code
            42  output
python      47  code
            51  output
python      58  teardown  "LAST"
-------------------------------------------------
3 test cases.

This command

phmdoctest doc/setup.md --setup FIRST --teardown LAST --outfile test_setup.py

creates the test file test_setup.py

Setup for sessions

The pytest option --doctest-modules is required to run doctest on sessions. pytest runs doctests in a separate context. For more on this see Execution context below.

To allow sessions to see the variables assigned by the --setup code block, add the option --setup-doctest

Here is an example with setup code and sessions setup_doctest.md. The first part of this file is a copy of setup.md.

This command uses the short form of setup and teardown. -u for setup and -d for teardown.

phmdoctest doc/setup_doctest.md -u FIRST -d LAST --setup-doctest --outfile test_setup_doctest.py

It creates the test file test_setup_doctest.py

Execution context

When run without --setup

With --setup

With share-names

With --setup and --setup-doctest

Same as the setup section plus:

pytest live logging demo

The live logging demos reveals pytest execution contexts. pytest Live Logs show the execution order of setup_module(), test cases, sessions, and teardown_module(). There are 2 demo invocations in the workflow action called pytest Live Log Demo. GitHub login required.

Send outfile to stdout

To redirect the above outfile to the standard output stream use one of these two commands.

Be sure to leave out --report when sending –outfile to standard output.

phmdoctest doc/example2.md -s "Python 3.7" -sLAST --outfile -

or

phmdoctest doc/example2.md -s "Python 3.7" -sLAST --outfile=-

Usage

phmdoctest --help

Usage: phmdoctest [OPTIONS] MARKDOWN_FILE

  MARKDOWN_FILE may also be .toml, .cfg, or .ini configuration file.

Options:
  --outfile TEXT       Write generated test case file to path TEXT. "-" writes
                       to stdout.

  -s, --skip TEXT      Any Python code or interactive session block that
                       contains the substring TEXT is not tested. More than
                       one --skip TEXT is ok. Double quote if TEXT contains
                       spaces. For example --skip="python 3.7" will skip every
                       Python block that contains the substring "python 3.7".
                       If TEXT is one of the 3 capitalized strings FIRST
                       SECOND LAST the first, second, or last Python code or
                       session block in the Markdown file is skipped.

  --report             Show how the Markdown fenced code blocks are used.

  --fail-nocode        This option sets behavior when the Markdown file has no
                       Python fenced code blocks or interactive session blocks
                       or if all such blocks are skipped. When this option is
                       present the generated pytest file has a test function
                       called test_nothing_fails() that will raise an
                       assertion. If this option is not present the generated
                       pytest file has test_nothing_passes() which will never
                       fail.

  -u, --setup TEXT     The Python code block that contains the substring TEXT
                       is run at test module setup time. Variables assigned at
                       the outer level are visible as globals to the other
                       Python code blocks. TEXT should match exactly one code
                       block. If TEXT is one of the 3 capitalized strings
                       FIRST SECOND LAST the first, second, or last Python
                       code or session block in the Markdown file is matched.
                       A block will not match --setup if it matches --skip, or
                       if it is a session block. Use --setup-doctest below to
                       grant Python sessions access to the globals.

  -d, --teardown TEXT  The Python code block that contains the substring TEXT
                       is run at test module teardown time. TEXT should match
                       exactly one code block. If TEXT is one of the 3
                       capitalized strings FIRST SECOND LAST the first,
                       second, or last Python code or session block in the
                       Markdown file is matched. A block will not match
                       --teardown if it matches either --skip or --setup, or
                       if it is a session block.

--setup-doctest        Make globals created by the --setup Python code block
                       or setup directive visible to session blocks and only
                       when they are tested with the pytest --doctest-modules
                       option.  Please note that pytest runs doctests in a
                       separate context that only runs doctests. This option
                       is ignored if there is no --setup option.

  --version            Show the version and exit.
  --help               Show this message and exit.

Run as a Python module

To run phmdoctest from the command line:

python -m phmdoctest doc/example2.md --report

Python API

Call main.testfile() to generate a pytest file in memory. Please see the Python API here. The example generates a pytest file from doc/setup.md and compares the result to doc/test_setup.py.

from pathlib import Path
import phmdoctest.main

generated_testfile = phmdoctest.main.testfile(
    "doc/setup.md",
    setup="FIRST",
    teardown="LAST",
)
expected = Path("doc/test_setup.py").read_text(encoding="utf-8")
assert expected == generated_testfile

pytest fixtures

Use fixture testfile_creator to generate a test file in memory. Pass the test file to fixture testfile_tester to run the test file in the pytester environment. Fixture API | Example. See more uses in tests/test_examples.py, tests/test_details.py, and tests/test_many_markdown.py. The fixtures run pytest much faster than run_and_pytest() below since there is no subprocess call. In the readthedocs documentation see the section Development tools API 1.4.0. pytest’s pytester is suitable for pytest plugin development.

Simulate command line

To simulate a command line call to phmdoctest from within a Python script phmdoctest.simulator offers the function run_and_pytest().

Please see the Latest Development tools API section or the docstring of the function run_and_pytest() in the file simulator.py. Pass pytest_options as a list of strings as shown below.

import phmdoctest.simulator

command = "phmdoctest doc/example1.md --report --outfile temporary.py"
simulator_status = phmdoctest.simulator.run_and_pytest(
    well_formed_command=command, pytest_options=["--doctest-modules", "-v"]
)
assert simulator_status.runner_status.exit_code == 0
assert simulator_status.pytest_exit_code == 0

Hints

Directive hints