有没有办法改进starlark的单元测试错误报告？

Question

我正在根据https://docs.bazel.build/versions/master/skylark/testing.html为我的项目编写分析时间测试，我想知道报告失败的最有用的方法是什么。

在使用unittest.bzl模块时，我使用了asserts.equals、asserts.true等工具，我发现日志中的错误报告有些缺失。例如，如果asserts.true失败，则错误消息为Expected condition to be true, but was false，没有提到哪一行，也没有提到它预期为真的条件。在一个包含大量测试的文件中，这并不是很有用！我知道可以将消息作为参数添加到这些断言中，但为每个断言定制消息也不太理想。有没有一种方法可以得到断言失败导致的回溯呢？或者访问断言失败的行号/详细信息的任何其他方式？

Answer 1

我从您的链接中获取了minimal example，并将latest Skylib版本添加到了一个新的工作区。然后，我更改了_provider_contents_test_impl中的期望值，使测试失败。

下面是完整的输出，请注意包含许多有用信息(文件、行、期望值、实际值)的DEBUG。

$ bazel test //mypkg:myrules_test                                             
DEBUG: /home/user/.cache/bazel/_bazel_user/863abec759a50d843603ddf033727331/external/bazel_skylib/lib/unittest.bzl:351:10: In test _provider_contents_test_impl from //mypkg:myrules_test.bzl: Expected "some valuexxxxx", but got "some value"
INFO: Analyzed target //mypkg:provider_contents_test (0 packages loaded, 0 targets configured).
INFO: Found 1 test target...
FAIL: //mypkg:provider_contents_test (see /home/user/.cache/bazel/_bazel_user/863abec759a50d843603ddf033727331/execroot/__main__/bazel-out/k8-fastbuild/testlogs/mypkg/provider_contents_test/test.log)
Target //mypkg:provider_contents_test up-to-date:
  bazel-bin/mypkg/provider_contents_test.sh
INFO: Elapsed time: 0.108s, Critical Path: 0.04s
INFO: 2 processes: 2 linux-sandbox.
INFO: Build completed, 1 test FAILED, 2 total actions
//mypkg:provider_contents_test                                           FAILED in 0.0s
  /home/user/.cache/bazel/_bazel_user/863abec759a50d843603ddf033727331/execroot/__main__/bazel-out/k8-fastbuild/testlogs/mypkg/provider_contents_test/test.log

INFO: Build completed, 1 test FAILED, 2 total actions

还支持Tracebacks，请参阅this bug report示例。

选项，实际值)。

$ bazel test //mypkg:myrules_test                                             
DEBUG: /home/user/.cache/bazel/_bazel_user/863abec759a50d843603ddf033727331/external/bazel_skylib/lib/unittest.bzl:351:10: In test _provider_contents_test_impl from //mypkg:myrules_test.bzl: Expected "some valuexxxxx", but got "some value"
INFO: Analyzed target //mypkg:provider_contents_test (0 packages loaded, 0 targets configured).
INFO: Found 1 test target...
FAIL: //mypkg:provider_contents_test (see /home/user/.cache/bazel/_bazel_user/863abec759a50d843603ddf033727331/execroot/__main__/bazel-out/k8-fastbuild/testlogs/mypkg/provider_contents_test/test.log)
Target //mypkg:provider_contents_test up-to-date:
  bazel-bin/mypkg/provider_contents_test.sh
INFO: Elapsed time: 0.108s, Critical Path: 0.04s
INFO: 2 processes: 2 linux-sandbox.
INFO: Build completed, 1 test FAILED, 2 total actions
//mypkg:provider_contents_test                                           FAILED in 0.0s
  /home/user/.cache/bazel/_bazel_user/863abec759a50d843603ddf033727331/execroot/__main__/bazel-out/k8-fastbuild/testlogs/mypkg/provider_contents_test/test.log

INFO: Build completed, 1 test FAILED, 2 total actions

还支持Tracebacks，请参阅this bug report示例。

请注意，asserts.equals将在失败时打印实际值，但asserts.true不会-但您可以通过使用asserts.equals(env, True, test_val, msg)轻松地解决此问题。