3. Development

This section only needs to be read by developers of the nocaselist project, including people who want to make a fix or want to test the project.

3.1. Repository

The repository for the nocaselist project is on GitHub:

https://github.com/pywbem/nocaselist

3.2. Setting up the development environment

If you have write access to the Git repo of this project, clone it using its SSH link, and switch to its working directory:
```
$ git clone git@github.com:pywbem/nocaselist.git
$ cd nocaselist
```
If you do not have write access, create a fork on GitHub and clone the fork in the way shown above.
It is recommended that you set up a virtual Python environment. Have the virtual Python environment active for all remaining steps.
Install the project for development. This will install Python packages into the active Python environment, and OS-level packages:
```
$ make develop
```
This project uses Make to do things in the currently active Python environment. The command:
```
$ make
```
displays a list of valid Make targets and a short description of what each target does.

3.3. Building the documentation

The ReadTheDocs (RTD) site is used to publish the documentation for the project package at https://nocaselist.readthedocs.io/

This page is automatically updated whenever the Git repo for this package changes the branch from which this documentation is built.

In order to build the documentation locally from the Git work directory, execute:

$ make builddoc

The top-level document to open with a web browser will be build_doc/html/docs/index.html.

3.4. Testing

All of the following make commands run the tests in the currently active Python environment. Depending on how the nocaselist package is installed in that Python environment, either the directories in the main repository directory are used, or the installed package. The test case files and any utility functions they use are always used from the tests directory in the main repository directory.

The tests directory has the following subdirectory structure:

tests
 +-- unittest            Unit tests

There are multiple types of tests:

Unit tests

These tests can be run standalone, and the tests validate their results automatically.

They are run by executing:
```
$ make test
```
Test execution can be modified by a number of environment variables, as documented in the make help (execute make help).

An alternative that does not depend on the makefile and thus can be executed from the source distribution archive, is:
```
$ ./setup.py test
```
Options for pytest can be passed using the --pytest-options option.

To run the unit tests in all supported Python environments, the Tox tool can be used. It creates the necessary virtual Python environments and executes make test (i.e. the unit tests) in each of them.

For running Tox, it does not matter which Python environment is currently active, as long as the Python tox package is installed in it:

$ tox                              # Run tests on all supported Python versions
$ tox -e py37                      # Run tests on Python 3.7

3.5. Testing from the source archives on Pypi or GitHub

The wheel distribution archives on Pypi (e.g. *.whl) contain only the files needed to run this package, but not the files needed to test it.

The source distribution archives on Pypi and GitHub (e.g. *.tar.gz) contain all files that are needed to run and to test this package. This allows testing the package without having to check out the entire repository, and is convenient for testing e.g. when packaging into OS-level packages. Nevertheless, the test files are not installed when installing these source distribution archives.

The following commands download the source distribution archive on Pypi for a particular version of the package into the current directory and unpack it:

$ pip download --no-deps --no-binary :all: nocaselist==1.0.0
$ tar -xf nocaselist-1.0.0.tar.gz
$ cd nocaselist-1.0.0
$ ls -1
-rw-r--r--   1 johndoe  staff    468 Jun 29 22:31 INSTALL.md
-rw-r--r--   1 johndoe  staff  26436 May 26 06:45 LICENSE.txt
-rw-r--r--   1 johndoe  staff    367 Jul  3 07:54 MANIFEST.in
-rw-r--r--   1 johndoe  staff   3451 Jul  3 07:55 PKG-INFO
-rw-r--r--   1 johndoe  staff   7665 Jul  2 23:20 README.rst
drwxr-xr-x  29 johndoe  staff    928 Jul  3 07:55 nocaselist
drwxr-xr-x   8 johndoe  staff    256 Jul  3 07:55 nocaselist.egg-info
-rw-r--r--   1 johndoe  staff   1067 Jun 29 22:31 requirements.txt
-rw-r--r--   1 johndoe  staff     38 Jul  3 07:55 setup.cfg
-rwxr-xr-x   1 johndoe  staff   7555 Jul  3 07:24 setup.py
-rw-r--r--   1 johndoe  staff   2337 Jul  2 23:20 test-requirements.txt
drwxr-xr-x  15 johndoe  staff    480 Jul  3 07:55 tests

This package, its dependent packages for running it, and its dependent packages for testing it can be installed with the package extra named “test”:

$ pip install .[test]

When testing in Linux distributions that include this package as an OS-level package, the corresponding OS-level packages would instead be installed for these dependent Python packages. The test-requirements.txt file shows which dependent Python packages are needed for testing this package.

Finally, the tests can be run using the setup.py script:

$ ./setup.py test

These commands are listed in the help of the setup.py script:

$ ./setup.py --help-commands

. . .

Extra commands:
  . . .
  test              Run unit tests using pytest
  . . .

The additional options supported by these commands are shown in their help:

$ ./setup.py test --help

. . .

Options for 'test' command:
  --pytest-options  additional options for pytest, as one argument

. . .

Note: The test command of setup.py is not the deprecated built-in command (see https://github.com/pypa/setuptools/issues/1684), but has been implemented in setup.py in such a way that it only runs the tests but does not install anything upfront. Therefore, this approach can be used for testing in Linux distributions that include this package as an OS-level package.

3.6. Contributing

Third party contributions to this project are welcome!

In order to contribute, create a Git pull request, considering this:

Test is required.
Each commit should only contain one “logical” change.
A “logical” change should be put into one commit, and not split over multiple commits.
Large new features should be split into stages.
The commit message should not only summarize what you have done, but explain why the change is useful.

What comprises a “logical” change is subject to sound judgement. Sometimes, it makes sense to produce a set of commits for a feature (even if not large). For example, a first commit may introduce a (presumably) compatible API change without exploitation of that feature. With only this commit applied, it should be demonstrable that everything is still working as before. The next commit may be the exploitation of the feature in other components.

For further discussion of good and bad practices regarding commits, see:

Further rules:

The following long-lived branches exist and should be used as targets for pull requests:
- master - for next functional version
- stable_$MN - for fix stream of released version M.N.
We use topic branches for everything!
- Based upon the intended long-lived branch, if no dependencies
- Based upon an earlier topic branch, in case of dependencies
- It is valid to rebase topic branches and force-push them.
We use pull requests to review the branches.
- Use the correct long-lived branch (e.g. master or stable_0.2) as a merge target.
- Review happens as comments on the pull requests.
- At least one approval is required for merging.
GitHub meanwhile offers different ways to merge pull requests. We merge pull requests by rebasing the commit from the pull request.

3.7. Releasing a version to PyPI

This section describes how to release a version of nocaselist to PyPI.

It covers all variants of versions that can be released:

Releasing a new major version (Mnew.0.0) based on the master branch
Releasing a new minor version (M.Nnew.0) based on the master branch
Releasing a new update version (M.N.Unew) based on the stable branch of its minor version

The description assumes that the pywbem/nocaselist Github repo is cloned locally and its upstream repo is assumed to have the Git remote name origin.

Any commands in the following steps are executed in the main directory of your local clone of the pywbem/nocaselist Git repo.

Set shell variables for the version that is being released and the branch it is based on:
- MNU - Full version M.N.U that is being released
- MN - Major and minor version M.N of that full version
- BRANCH - Name of the branch the version that is being released is based on
When releasing a new major version (e.g. 1.0.0) based on the master branch:
```
MNU=1.0.0
MN=1.0
BRANCH=master
```
When releasing a new minor version (e.g. 0.9.0) based on the master branch:
```
MNU=0.9.0
MN=0.9
BRANCH=master
```
When releasing a new update version (e.g. 0.8.1) based on the stable branch of its minor version:
```
MNU=0.8.1
MN=0.8
BRANCH=stable_${MN}
```

Create a topic branch for the version that is being released:

git checkout ${BRANCH}
git pull
git checkout -b release_${MNU}

Edit the version file:
```
vi nocaselist/_version.py
```
and set the __version__ variable to the version that is being released:
```
__version__ = 'M.N.U'
```
Edit the change log:
```
vi docs/changes.rst
```
and make the following changes in the section of the version that is being released:
- Finalize the version.
- Change the release date to today’s date.
- Make sure that all changes are described.
- Make sure the items shown in the change log are relevant for and understandable by users.
- In the “Known issues” list item, remove the link to the issue tracker and add text for any known issues you want users to know about.
- Remove all empty list items.

Commit your changes and push the topic branch to the remote repo:

git status  # Double check the changed files
git commit -asm "Release ${MNU}"
git push --set-upstream origin release_${MNU}

On GitHub, create a Pull Request for branch release_M.N.U. This will trigger the CI runs.

Important: When creating Pull Requests, GitHub by default targets the master branch. When releasing based on a stable branch, you need to change the target branch of the Pull Request to stable_M.N.
On GitHub, close milestone M.N.U.
On GitHub, once the checks for the Pull Request for branch start_M.N.U have succeeded, merge the Pull Request (no review is needed). This automatically deletes the branch on GitHub.

Add a new tag for the version that is being released and push it to the remote repo. Clean up the local repo:

git checkout ${BRANCH}
git pull
git tag -f ${MNU}
git push -f --tags
git branch -d release_${MNU}

When releasing based on the master branch, create and push a new stable branch for the same minor version:
```
git checkout -b stable_${MN}
git push --set-upstream origin stable_${MN}
git checkout ${BRANCH}
```
Note that no GitHub Pull Request is created for any stable_* branch.
When releasing based on the master branch, activate the new version stable_M.N on ReadTheDocs:
- Go to https://readthedocs.org/projects/nocaselist/versions/ and log in.
- Activate the new version stable_M.N.
  
  This triggers a build of that version. Verify that the build succeeds and that new version is shown in the version selection popup at https://nocaselist.readthedocs.io/
On GitHub, edit the new tag M.N.U, and create a release description on it. This will cause it to appear in the Release tab.

You can see the tags in GitHub via Code -> Releases -> Tags.
Upload the package to PyPI:
```
make upload
```
This will show the package version and will ask for confirmation.

Attention! This only works once for each version. You cannot release the same version twice to PyPI.

Verify that the released version arrived on PyPI at https://pypi.python.org/pypi/nocaselist/

3.8. Starting a new version

This section shows the steps for starting development of a new version of the nocaselist project in its Git repo.

This section covers all variants of new versions:

Starting a new major version (Mnew.0.0) based on the master branch
Starting a new minor version (M.Nnew.0) based on the master branch
Starting a new update version (M.N.Unew) based on the stable branch of its minor version

The description assumes that the pywbem/nocaselist Github repo is cloned locally and its upstream repo is assumed to have the Git remote name origin.

Any commands in the following steps are executed in the main directory of your local clone of the pywbem/nocaselist Git repo.

Set shell variables for the version that is being started and the branch it is based on:
- MNU - Full version M.N.U that is being started
- MN - Major and minor version M.N of that full version
- BRANCH - Name of the branch the version that is being started is based on
When starting a new major version (e.g. 1.0.0) based on the master branch:
```
MNU=1.0.0
MN=1.0
BRANCH=master
```
When starting a new minor version (e.g. 0.9.0) based on the master branch:
```
MNU=0.9.0
MN=0.9
BRANCH=master
```
When starting a new minor version (e.g. 0.8.1) based on the stable branch of its minor version:
```
MNU=0.8.1
MN=0.8
BRANCH=stable_${MN}
```

Create a topic branch for the version that is being started:

git checkout ${BRANCH}
git pull
git checkout -b start_${MNU}

Edit the version file:
```
vi nocaselist/_version.py
```
and update the version to a draft version of the version that is being started:
```
__version__ = 'M.N.U.dev1'
```

Edit the change log:

vi docs/changes.rst

and insert the following section before the top-most section:

nocaselist M.N.U.dev1
---------------------

Released: not yet

**Incompatible changes:**

**Deprecations:**

**Bug fixes:**

**Enhancements:**

**Cleanup:**

**Known issues:**

* See `list of open issues`_.

.. _`list of open issues`: https://github.com/pywbem/nocaselist/issues

Commit your changes and push them to the remote repo:

git status  # Double check the changed files
git commit -asm "Start ${MNU}"
git push --set-upstream origin start_${MNU}

On GitHub, create a Pull Request for branch start_M.N.U.

Important: When creating Pull Requests, GitHub by default targets the master branch. When starting a version based on a stable branch, you need to change the target branch of the Pull Request to stable_M.N.
On GitHub, create a milestone for the new version M.N.U.

You can create a milestone in GitHub via Issues -> Milestones -> New Milestone.
On GitHub, go through all open issues and pull requests that still have milestones for previous releases set, and either set them to the new milestone, or to have no milestone.
On GitHub, once the checks for the Pull Request for branch start_M.N.U have succeeded, merge the Pull Request (no review is needed). This automatically deletes the branch on GitHub.

Update and clean up the local repo:

git checkout ${BRANCH}
git pull
git branch -d start_${MNU}