#137 Advanced Python testing and big-time diffs
Published July 2, 2019
28 min
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    Sponsored by Rollbar: https://pythonbytes.fm/rollbar

    Brian #1: Comparing the Same Project in Rust, Haskell, C++, Python, Scala and OCaml

    • Tristan Hume, writing about a university project
    • Teams of up to 3 people, multi month, write a Java to x86 compiler in language of choice
    • Needed to pass both known and unknown tests.
    • Secret tests to be run after submission encouraged teams to add more testing than provided.
    • Nothing but standard libraries, and no parsing libraries, even if in standard.
    • Lines of code
      • Rust baseline
      • Haskell: 1-1.6x
      • C++: 1.4x
      • Rust (another team): 3x
      • Scala: 0.7 x
      • OCaml: 1-1.6x
      • Python: about half the size
    • Python version
      • one person
      • used metaprogramming
      • more extra features than any other team
      • passed all public and secret tests

    Michael #2 : Pylustrator is a program to style your matplotlib plots

    • via Len Wanger
    • Pylustrator is a program to style your matplotlib plots for publication.
    • Subplots can be resized and dragged around by the mouse, text and annotations can be added.
    • Changes can be saved to the initial plot file as python code.

    Brian #3: MongoDB 4.2

    • Distributed Transactions
      • extends multi-document ACID transactions across documents, collections, dbs in a replica set, and sharded cluster.
    • Field Level Encryption
      • encryption done on client side
      • satisfies GDPR by allowing customer key destruction rendering server data on customer useless.
      • system administration can be done with no exposure to private data

    Michael #4: Deep Difference and search of any Python object/data

    • via François Leblanc
    • DeepDiff: Deep Difference of dictionaries, iterables, strings and other objects. It will recursively look for all the changes.
    • Lots of nice touches:
      • List difference ignoring order or duplicates
      • Report repetitions
      • Exclude certain types from comparison
      • Exclude part of your object tree from comparison
      • Significant Digits
    • DeepSearch: Search for objects within other objects.
    • DeepHash: Hash of ANY python object based on its contents even if the object is not considered hashable! DeepHash is supposed to be deterministic in order to make sure 2 objects that contain the same data, produce the same hash.

    Brian #5: Advanced Python Testing

    • Josh Peak
    • “This article is mostly for me to process my thoughts but also to pave a path for anyone that wants to follow a similar journey on some more advanced python testing topics.”
    • Learning journey (including some great podcasts and an awesome book on testing)
    • Testing tools
      • basic test structure
      • adding black to testing with pytest-black
      • linting with pylint
        • including a very cool speed up trick to only lint modified files.
      • flake8, including docstring checking
      • tox.ini modifications
      • code coverage goals and how to ratchet up to that goal with --cov-fail-under
        • cool learning: “Increase code coverage by testing more code OR deleting code.”
      • fixtures for database connections
      • utilizing mocks, spies, stubs, and monkey patches, including pytest-mock
      • pytest-vcr to save network interactions and replay them in future test runs, resulting in a 10x speedup.
    • Lots of links and tangents possible from this article.

    Michael #6: Understanding Python's del

    • via Kevin Buchs
    • Official docs
    • General confusion of what this does
    • Looks like memory management, and it mostly isn’t
    • Primary use: remove an item from a list given its index instead of its value or from a dictionary given its key: del person['profession'] # person is a dict
    • del statement can also be used to remove slices from a list del lst[2:4]
    • del can also be used to delete entire variables: del variable
    • Recently covered how The CPython Bytecode Compiler is Dumb. Proactive dels could help.




    Optimist: The glass is half full. Pessimist: The glass is half empty. Programmer: The glass is twice as large as necessary.

    Pragmatist: allowing room for requirements oversights, scope creep, and schedule overrun.

    From “The Upside” with Kevin Hart and Bryan Cranston (watched it last night): K: Would you invest in [HTML_REMOVED]? B: That seems too niche. K: What’s “niche” mean? B: It’s the girl version of “nephew”.

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