|
| 1 | +--- |
| 2 | +layout:post |
| 3 | +title:"How to contribute to RustPython by CPython unittest" |
| 4 | +date:2020-04-05 01:45:00 +0900 |
| 5 | +categories:guideline |
| 6 | +--- |
| 7 | + |
| 8 | +At the very end of 2019, we finally reached one of the short-term goals: CPython unittest support. Due to this enhancement, finding CPython compatibility is easier than before. |
| 9 | +Probably this will be the major source of contribution spots for the new contributors this year. Here is a simple guideline. |
| 10 | + |
| 11 | +##Fix known compatibility bugs |
| 12 | +Let's find an incompatibility issue and fix it. |
| 13 | + |
| 14 | +1. See`Lib/test` directory of the project. There are many`test_` prefixed files like`test_unicode.py`. |
| 15 | +2. Try to open one of them. It might look just fine at a glance - but search for`TODO: RUSTPYTHON` in the files. There are tons of skipped, marked as an expected failure or commented out tests. |
| 16 | +3. Choose one or two interesting bugs. Remove the test blocker - skip, expectedFailure or comments. |
| 17 | +4. Try to fix them. |
| 18 | + |
| 19 | +Here is a quick tip to run single unittest file. |
| 20 | + |
| 21 | +```sh |
| 22 | +$ RUSTPYTHONPATH=Lib cargo run --release Lib/test/test_unicode.py |
| 23 | +``` |
| 24 | + |
| 25 | +##Add a new unittest file |
| 26 | +Because CPython unittest is not perfectly working in RustPython, we are doing this one by one with editings. |
| 27 | +1. Download CPython source code. |
| 28 | +2. Check out a specific version of CPython. For now, 3.8.2 is recommended. (We are testing against CPython 3.8 and 3.8.2 is the most recent version for now) |
| 29 | +3. Copy a file from CPython`Lib/test` |
| 30 | +4. Commit the file without editing. Specify copied CPython version to commit message. |
| 31 | +5. Try to edit it until it runs without a crash or failure. |
| 32 | +6. Commit the changes to make it run. This is the core contribution. |
| 33 | + |
| 34 | +Because RustPython is not perfect, "try to edit it until it runs" doesn't mean to make 100% successful running. The common editing methods here: |
| 35 | +1. At least it must be able to start to run the test. Fix the test code or bug until it runs at least a single unit of the test. Typically, unimplemented stdlib or missing files of unittest can make issues. Sometimes RustPython bugs make issues too. |
| 36 | +2. If any test is not loadable by`SyntaxError`, that part is required to be commented out. |
| 37 | +3. If any test leads to a crash of RustPython, this code is not possible to run. Mark the test to skip. |
| 38 | +4. If any test is run but fails, this is an incompatibility issue. Mark the test as an expected failure. |
| 39 | + |
| 40 | +We prefer the reversed order of upper methods. The later the more strict so easy to detect any progress or regression. |
| 41 | +When we temporarily disable parts of unittest due to RustPython caveats, we mark them to find it out easily later. Please check the examples below or search for`TODO: RUSTPYTHON` in`Lib/test` directory to check actual usage. |
| 42 | + |
| 43 | +Comment out: |
| 44 | +```python |
| 45 | +#TODO: RUSTPYTHON |
| 46 | +# |
| 47 | +# def ... # commented out tests |
| 48 | +``` |
| 49 | + |
| 50 | +skip: |
| 51 | +```python |
| 52 | +@unittest.skip("TODO: RUSTPYTHON") |
| 53 | +def...# skipped tests |
| 54 | +``` |
| 55 | + |
| 56 | +expectedFailure: |
| 57 | +```python |
| 58 | +#TODO: RUSTPYTHON |
| 59 | +@unittest.expectedFailure |
| 60 | +def...# failed tests |
| 61 | +``` |
| 62 | + |
| 63 | +##Development guide |
| 64 | +For the general source of the development, please visit the[RustPython development guide](https://github.com/RustPython/RustPython/blob/master/DEVELOPMENT.md) |