mirror of https://github.com/dense-analysis/ale
312 lines
14 KiB
Plaintext
312 lines
14 KiB
Plaintext
*ale-development.txt* For Vim version 8.0.
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*ale-development*
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ALE Development Documentation
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===============================================================================
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CONTENTS *ale-development-contents*
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1. Introduction.........................|ale-development-introduction|
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2. Design Goals.........................|ale-design-goals|
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3. Coding Standards.....................|ale-coding-standards|
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4. Testing ALE..........................|ale-development-tests|
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4.1. Writing Linter Tests.............|ale-development-linter-tests|
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===============================================================================
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1. Introduction *ale-development-introduction*
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This document contains helpful information for ALE developers, including
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design goals, information on how to run the tests, coding standards, and so
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on. You should read this document if you want to get involved with ALE
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development.
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===============================================================================
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2. Design Goals *ale-design-goals*
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This section lists design goals for ALE, in no particular order. They are as
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follows.
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ALE code should be almost 100% VimL. This makes the plugin as portable as
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possible.
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ALE should run without needing any other plugins to be installed, to make
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installation simple. ALE can integrate with other plugins for more advanced
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functionality, non-essential functionality, or improving on basic first party
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functionality.
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ALE should check files with as many tools as possible by default, except where
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they cause security issues or make excessive use of resources on modern
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machines.
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ALE should be free of breaking changes to the public API, which is comprised of
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documented functions and options, until a major version is planned. Breaking
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changes should be preceded by a deprecation phase complete with warnings.
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Changes required for security may be an exception.
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ALE supports Vim 8 and above, and NeoVim 0.2.0 or newer. These are the
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earliest versions of Vim and NeoVim which support |job|, |timer|, |closure|,
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and |lambda| features. All ALE code should be written so it is compatible with
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these versions of Vim, or with version checks so particular features can
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degrade or fail gracefully.
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Just about everything should be documented and covered with tests.
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By and large, people shouldn't pay for the functionality they don't use. Care
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should be taken when adding new features, so supporting new features doesn't
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degrade the general performance of anything ALE does.
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LSP support will become more important as time goes on. ALE should provide
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better support for LSP features as time goes on.
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When merging pull requests, you should respond with `Cheers! :beers:`, purely
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for comedy value.
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===============================================================================
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3. Coding Standards *ale-coding-standards*
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The following general coding standards should be adhered to for Vim code.
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* Check your Vim code with `Vint` and do everything it says. ALE will check
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your Vim code with Vint automatically. See: https://github.com/Kuniwak/vint
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Read ALE's `Dockerfile` to see which version of `Vint` it uses.
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* Try to write descriptive and concise names for variables and functions.
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Names shouldn't be too short or too long. Think about others reading your
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code later on.
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* Use `snake_case` names for variables and arguments, and `PascalCase` names
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for functions. Prefix every variable name with its scope. (`l:`, `g:`, etc.)
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* Try to keep lines no longer than 80 characters, but this isn't an absolute
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requirement.
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* Use 4 spaces for every level of indentation in Vim code.
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* Add a blank line before every `function`, `if`, `for`, `while`, or `return`,
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which doesn't start a new level of indentation. This makes the logic in
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your code easier to follow.
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* End every file with a trailing newline character, but not with extra blank
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lines. Remove trailing whitespace from the ends of lines.
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* Write the full names of commands instead of abbreviations. For example, write
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`function` instead of `func`, and `endif` instead of `end`.
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* Write functions with `!`, so files can be reloaded. Use the |abort| keyword
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for all functions, so functions exit on the first error.
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* Make sure to credit yourself in files you have authored with `Author:`
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and `Description:` comments.
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In addition to the above general guidelines for the style of your code, you
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should also follow some additional rules designed to prevent mistakes. Some of
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these are reported with ALE's `custom-linting-rules` script. See
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|ale-development-tests|.
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* Don't leave stray `:echo` lines in code. Use `execute 'echo' ...` if you must
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echo something.
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* For strings use |is#| instead of |==#|, `is?` instead of `==?`, `isnot#`
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instead of `!=#`, and `isnot?` instead of `!=?`. This is because `'x' ==# 0`
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returns 1, while `'x' is# 0` returns 0, so you will experience fewer issues
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when numbers are compared with strings. `is` and `isnot` also do not throw
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errors when other objects like List or Dictionaries are compared with
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strings.
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* Don't use the `getcwd()` function in the ALE codebase. Most of ALE's code
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runs from asynchronous callback functions, and these functions can execute
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from essentially random buffers. Therefore, the `getcwd()` output is
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useless. Use `expand('#' . a:buffer . ':p:h')` instead. Don't use
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`expand('%...')` for the same reason.
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* Don't use the `simplify()` function. It doesn't simplify paths enough. Use
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`ale#path#Simplify()` instead.
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* Don't use the `shellescape()` function. It doesn't escape arguments properly
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on Windows. Use `ale#Escape()` instead, which will avoid escaping where it
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isn't needed, and generally escape arguments better on Windows.
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* Don't use the `tempname()` function. It doesn't work when `$TMPDIR` isn't
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set. Use `ale#util#Tempname()` instead, which temporarily sets `$TMPDIR`
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appropriately where needed.
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* Use `snake_case` names for linter names, so they can be used as part of
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variable names. You can define `aliases` for linters, for other names people
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might try to configure linters with.
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Apply the following guidelines when writing Vader test files.
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* Use 2 spaces for Vader test files, instead of the 4 spaces for Vim files.
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* If you write `Before` and `After` blocks, you should typically write them at
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the top of the file, so they run for all tests. There may be some tests
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where it make sense to modify the `Before` and `After` code part of the way
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through the file.
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* If you modify any settings or global variables, reset them in `After`
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blocks. The Vader `Save` and `Restore` commands can be useful for this
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purpose.
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* If you load or define linters in tests, write `call ale#linter#Reset()` in
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an `After` block.
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* Just write `Execute` blocks for Vader tests, and don't bother writing `Then`
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blocks. `Then` blocks execute after `After` blocks in older versions, and
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that can be confusing.
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Apply the following rules when writing Bash scripts.
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* Run `shellcheck`, and do everything it says.
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See: https://github.com/koalaman/shellcheck
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* Try to write scripts so they will run on Linux, BSD, or Mac OSX.
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===============================================================================
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4. Testing ALE *ale-development-tests*
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ALE is tested with a suite of tests executed in Travis CI and AppVeyor. ALE
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runs tests with the following versions of Vim in the following environments.
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1. Vim 8.0.0027 on Linux via Travis CI.
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2. Vim 8.1.0204 on Linux via Travis CI.
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3. NeoVim 0.2.0 on Linux via Travis CI.
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4. NeoVim 0.3.0 on Linux via Travis CI.
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5. Vim 8 (stable builds) on Windows via AppVeyor.
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If you are developing ALE code on Linux, Mac OSX, or BSD, you can run ALEs
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tests by installing Docker and running the `run-tests` script. Follow the
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instructions on the Docker site for installing Docker.
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See: https://docs.docker.com/install/
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NOTE: Don't forget to add your user to the `docker` group on Linux, or Docker
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just won't work. See: https://docs.docker.com/install/linux/linux-postinstall/
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If you run simply `./run-tests` from the ALE repository root directory, the
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latest Docker image for tests will be downloaded if needed, and the script
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will run all of the tests in Vader, Vint checks, and several Bash scripts for
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finding extra issues. Run `./run-tests --help` to see all of the options the
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script supports. Note that the script supports selecting particular test files.
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Generally write tests for any changes you make. The following types of tests
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are recommended for the following types of code.
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* New/edited error handler callbacks -> Write tests in `test/handler`
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* New/edited command callbacks -> Write tests in `test/command_callback`
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* New/edited fixer functions -> Write tests in `test/fixers`
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Look at existing tests in the codebase for examples of how to write tests.
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Refer to the Vader documentation for general information on how to write Vader
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tests: https://github.com/junegunn/vader.vim
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See |ale-development-linter-tests| for more information on how to write linter
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tests.
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When you add new linters or fixers, make sure to add them into the table in
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the README, and also into the |ale-support| list in the main help file. If you
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forget to keep them both in sync, you should see an error like the following
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in Travis CI. >
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========================================
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diff README.md and doc/ale.txt tables
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========================================
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Differences follow:
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--- /tmp/readme.qLjNhJdB 2018-07-01 16:29:55.590331972 +0100
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+++ /tmp/doc.dAi8zfVE 2018-07-01 16:29:55.582331877 +0100
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@@ -1 +1 @@
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- ASM: gcc, foobar
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+ ASM: gcc
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<
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Make sure to list documentation entries for linters and fixers in individual
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help files in the table of contents, and to align help tags to the right
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margin. For example, if you add a heading for an `aardvark` tool to
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`ale-python.txt` with a badly aligned doc tag, you will see errors like so. >
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========================================
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Look for badly aligned doc tags
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========================================
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Badly aligned tags follow:
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doc/ale-python.txt:aardvark ...
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========================================
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Look for table of contents issues
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========================================
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Check for bad ToC sorting:
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Check for mismatched ToC and headings:
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--- /tmp/table-of-contents.mwCFOgSI 2018-07-01 16:33:25.068811878 +0100
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+++ /tmp/headings.L4WU0hsO 2018-07-01 16:33:25.076811973 +0100
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@@ -168,6 +168,7 @@
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pyrex (cython), ale-pyrex-options
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cython, ale-pyrex-cython
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python, ale-python-options
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+ aardvark, ale-python-aardvark
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autopep8, ale-python-autopep8
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black, ale-python-black
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flake8, ale-python-flake8
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<
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Make sure to make the table of contents match the headings, and to keep the
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doc tags on the right margin.
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===============================================================================
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4.1 Writing Linter Tests *ale-development-linter-tests*
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Tests for ALE linters take two forms.
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1. Tests for handling the output of commands.
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2. Tests for checking which commands are run, or connections are made.
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Tests of the first form should go in the `test/handler` directory, and should
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be written like so. >
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Before:
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" Load the file which defines the linter.
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runtime ale_linters/filetype/linter_name_here.vim
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After:
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" Unload all linters again.
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call ale#linter#Reset()
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Execute(The output should be correct):
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" Test that the right loclist items are parsed from the handler.
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AssertEqual
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\ [
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\ {
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\ 'lnum': 1,
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\ 'type': 'E',
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\ 'text': 'Something went wrong',
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\ },
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\ ],
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\ ale_linters#filetype#linter_name#Handle(bufnr(''), [
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\ '1:Something went wrong',
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\ ]
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<
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Tests for what ALE runs should go in the `test/command_callback` directory,
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and should be written like so. >
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Before:
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" Load the linter and set up a series of commands, reset linter variables,
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" clear caches, etc.
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"
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" Vader's 'Save' command will be called here for linter variables.
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call ale#assert#SetUpLinterTest('filetype', 'linter_name')
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After:
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" Reset linters, variables, etc.
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"
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" Vader's 'Restore' command will be called here.
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call ale#assert#TearDownLinterTest()
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Execute(The default command should be correct):
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" AssertLinter checks the executable and command.
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" Pass expected_executable, expected_command
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AssertLinter 'some-command', ale#Escape('some-command') . ' --foo'
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Execute(Check chained commands):
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" WithChainResults can be called with 1 or more list for passing output
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" to chained commands. The output for each callback defaults to an empty
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" list.
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WithChainResults ['v2.1.2']
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" Given a List of commands, check all of them.
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" Given a String, only the last command in the chain will be checked.
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AssertLinter 'some-command', [
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\ ale#Escape('some-command') . ' --version',
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\ ale#Escape('some-command') . ' --foo',
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\]
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<
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The full list of commands that will be temporarily defined for linter tests
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given the above setup are as follows.
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`WithChainResults [...]` - Define output for command chain functions.
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`AssertLinter executable, command` - Check the executable and command.
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`AssertLinterNotExecuted` - Check that linters will not be executed.
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`AssertLSPLanguage language` - Check the language given to an LSP server.
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`AssertLSPOptions options_dict` - Check the options given to an LSP server.
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`AssertLSPProject project_root` - Check the root given to an LSP server.
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===============================================================================
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vim:tw=78:ts=2:sts=2:sw=2:ft=help:norl:
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