pytest-bazel 0.0.2

A pytest runner with bazel support

pytest-bazel

A pytest wrapper for supporting bazel's rule_python. This is supposed to be used via PyPI and no bazel rules will be exported for the time being.

Goals

• Looking at the test_encyclopedia, the following can be still added:
  • --capture=no depending on whether bazel run or bazel test is used.
  • TEST_WARNINGS_OUTPUT_FILE is used to output warnings.warn usage.
  • TEST_TMPDIR is used
  • TEST_SRCDIR is maybe used to pass in the root where to start discovery.
  • TEST_RANDOM_SEED is used for predictive tests.
  • TEST_INFRASTRUCTURE_FAILURE_FILE is used when pytest fails to discover any tests.
• Consider recommendations on project structure (separate tests dir may facilitate integration with pytest, but this needs further checking).
• rules_python FR are submitted.
• No passing of files as args is needed. Pytest discovery is working as expected.

Usage

NOTE, this is not fully tested and is in a very early POC state!

Pattern 1

Using it as an alternative to unittest.main() in a py_test rule.

import pytest_bazel

...

if __name__ == "__main__":
    pytest_bazel.main()

# BUILD.bazel contents
load("@rules_python//python:py_test.bzl", "py_test")

py_test(
    name = "my_test",
    # ...
    deps = ["@pypi//pytest_bazel"],
)

Pattern 2

Using it to create a macro, this shows how to create a replacement for the rules_python_pytest py_pytest_test macro. The benefit is that this defines all of the necessary files in a single place.

# pytest_test.bzl contents
load("@rules_python//python:py_test.bzl", "py_test")
load("@rules_python//python:py_library.bzl", "py_library")
load("@rules_python//python/entry_points:py_console_script_binary.bzl", "py_console_script_binary")

def pytest_test(name, visibility = None, **kwargs):
    # this is only needed for passing srcs
    py_library(
        name = name + ".lib",
        #testonly = True,
        **kwargs,
    )

    py_console_script_binary(
        name = "test_simple",
        pkg = "@pypi//pytest_bazel",  # assuming your hub repo name is `pypi`.
        binary_rule = py_test,
        deps = [
            # The test sources are here
            name + ".lib",
            # Add extra test deps below, e.g. for sharding support, etc.
        ],
        # TODO @aignas 2024-06-29: support testonly here
        #testonly = True,
        # The following is reusing the ideas defined in
        # https://github.com/caseyduquettesc/rules_python_pytest/blob/main/python_pytest/defs.bzl
        args = kwargs.get("args", []) + [
            "$(location :%s)" % x for x in srcs],
        ],
    )

# BUILD.bazel contents
load("//:pytest_test.bzl", "pytest_test")

pytest_test(
    name = "my_test",
    # ...
    deps = ["@pypi//pytest_bazel"],
)

Changelog

See changelog.

Contributing

This is right now too early to be contributed to code-wise, but issues welcome describing what you would like to have in this project.

Thanks

Special thanks to rules_python_pytest and rules_py projects that had some great ideas how to integrate with pytest. This attempts to unify all of the approaches.