istant

A Python package to check if an object is of a certain type in an instant.

Development

• poetry install
• poetry shell
• pytest

Tech Stack

Packaging and Development

• Poetry
• Mypy
• isort
• Black
• Flake8
  • flake8-bugbear
  • flake8-comprehensions
  • pep8-naming
  • flake8-builtins
• Bandit

This package was created with Cookiecutter and the joaopalmeiro/cookiecutter-templates/python-pkg project template.

References

• How to check if a string is upper, lower, or mixed case in Python.
• python-string-utils package.

Notes

• pyenv:
  • pyenv local 3.6.13. It generates a .python-version file. It is similar to the .nvmrc file (nvm).
  • Should we gitignore the .python-version file?.
• Vim:
  • Learning tools:
    • VIM-ADVENTURES.
    • OpenVim.
    • Vim Cheat Sheet.
  • Two basic modes:
    • insert mode (i): to write text (like in a text editor).
    • normal mode (Esc): to navigate and manipulate text.
  • Basic movement: h (←), j (↓), k (↑), and l (→).
  • Word movement:
    • w: start of the next word.
    • e: end of the word.
    • b: beginning of the word.
    • These keys can be combined with a number (number powered movement). 3w is the same as pressing w 3x, for example.
  • Insert text repeatedly: 30 + i + - + Esc to insert - 30x, for example.
  • Find a character:
    • f: next occurrence of a character.
    • F: previous occurrence of a character.
    • fo to find the next o, for example.
    • These keys can also be combined with numbers.
  • Go to matching parentheses: %.
  • Go to start/end of line: 0/$.
  • Find word under cursor:
    • *: next occurrence.
    • #: previous occurrence.
  • Go to beginning/end of file: gg/G. G can be combined with a number too.
  • Search:
    • /<text>.
    • n: next occurrence.
    • N: previous occurrence.
  • Insert new line:
    • o: below the current line.
    • O: above the current line.
    • The editor is set to insert mode.
  • Remove a character:
    • x: under the cursor.
    • X: to the left of the cursor.
  • Replace a character:
    • r.
    • Under the cursor, without switching to insert mode.
  • Delete:
    • d.
    • It can be combined with numbers and movement keys (dw and d2e, for example).
    • It copies the content. Content can be pasted with p.
  • Repeat the previous command: ..
  • Visual mode:
    • v.
    • To select text with the movement keys first and then apply a command.
  • Exiting:
    • :w: save.
    • :q: quit.
    • :q!: quit without saving.
  • Editing:
    • u: undo.
    • Ctrl + r: redo.
  • Vim.gitignore file.

VIM and Python – A Match Made in Heaven

Source.

• .vimrc file.
• vim --version.
• *nix or Unix-like systems.
• Check the Python version used in Vim: :python import sys; print(sys.version).
• Extensions or bundles or plugins.
• Vundle:
  • pip for Vim/Vim plugin manager.
  • git clone https://github.com/VundleVim/Vundle.vim.git ~/.vim/bundle/Vundle.vim.
  • Extensions can be managed from the .vimrc file (touch ~/.vimrc) + :PluginInstall.
• Split layouts:
  • :sp <filename>: vertical split.
  • :vs <filename>: horizontal split.
• vscode-viml-syntax (VS Code extension).
• Buffers:
  • Think of a buffer as a recently opened file.
  • :b <buffer name or number>: switch to an open buffer.
  • :ls: list all buffers.
• Extensions:
  • SimpylFold (code folding).
  • indentpython.vim.
  • YouCompleteMe (auto-complete). Installation instructions.
  • syntastic (syntax checking).
  • vim-flake8.
  • NERDTree (file browsing).
  • CtrlP (searching).
  • fugitive.vim (Git integration).
  • Powerline (status bar).

Effective Python Testing With Pytest

Source.

• poetry add -D pytest.
• Arrange (set up)-Act-Assert model.
• pytest allows you to use Python's assert directly.
• Test double: an object that stands in for another object during a test (source), such as mocks, for example.
• Fixtures (@pytest.fixture decorator + conftest.py file):
  • Functions that create data/test doubles or initialize some system state for the test suite.
  • They are appropriate to be used across multiple tests.
  • They are used as arguments (explicit dependency declarations).
  • They are modular, so they can depend on other fixtures.
• Test filtering:
  • Name-based filtering (-k).
  • Directory scoping.
  • Test categorization (-m <name> or -m "not <name>"). pytest allows you to create marks (custom labels) for any test.
• Test parameterization.
• Plugin-based architecture.
• monkeypatch fixture (+ @pytest.fixture(autouse=True) in the conftest.py file): to safely patch and mock functionality in tests, allowing to set/delete an attribute, dictionary item, or environment variable, for example (requests.get(), for example).
• Marks (@pytest.mark.<name>):
  • It is possible to register marks in the pytest.ini file (or in the pyproject.toml file). This can be combined with the --strict-markers flag to ensure that all marks in the tests are registered in the pytest configuration. On the other hand, addopts = --strict-markers can be added to the pytest.ini file.
  • Run pytest --markers to check the list of marks.
  • skip: to skip a test.
  • skipif: to skip a test if the expression passed to it evaluates to True.
  • xfail: a test is expected to fail.
  • parametrize. The first argument is a comma-delimited string of parameter names. The second argument is a list of either tuples or single values.
• --durations flag:
  • To include a duration report in the results.
  • --durations=3 to report the slowest 3 tests, for example.
• Plugins:
  • List.
  • pytest-randomly: to run the tests in a random order.
  • pytest-cov: to generate coverage reports (coverage.py package).
  • pytest-bdd (for behavior-driven development).

PyCharm

• Uninstall PyCharm.
• Black integration.
• open -na "PyCharm CE.app" (source).