golden example tests

The tests in this package are used to:

1. check that gazelle runs properly (generates correct output from BUILD.in to BUILD.out)
2. assert that the build artifacts can actually be built (bazel build //...).

//example/golden:golden_test runs the gazelle tests. Each subdirectory of testdata/* represents a separate test. The BUILD.in file is used as the base, and BUILD.out is expected to be generated. If there is a diff against the actual BUILD.out, the test fails.

The individual gazelle_testdata_example tests package up specific examples and generate a go_bazel_test for the example. So for //example/golden:java, a //example/golden:java_test will run a test that actually tries to build everything within the workspace based on the contents of BUILD.out.

these are currently tagged manual due to timeouts in CI.

debugging golden example tests

Have any BUILD.bazel files crept into the vendor/ tree? These are globbed in //:all_files and the presence of one will elide files in that package from the glob. You might not see them because they are .gitignored.

$ bazel query //:all_files --output build > all_files.BUILD

Try and build from the main test workspace. To do that, open up rules_go in the external tree and disable the cleanup function. For example:

$ (cd $(bazel info output_base)/external/io_bazel_rules_go && code .)
$ code go/tools/bazel_testing/bazel_testing.go

    workspaceDir, cleanup, err := setupWorkspace(args, files)
    defer func() {
+       if err == nil {
+           log.Println("NOTE: skipping cleanup")
+           return
+       }
        if err := cleanup(); err != nil {
            fmt.Fprintf(os.Stderr, "cleanup error: %v\n", err)
            // Don't fail the test on a cleanup error.
            // Some operating systems (windows, maybe also darwin) can't reliably
            // delete executable files after they're run.
        }
    }()

Then, go into the directory that the go_bazel_test creates and run bazel there directly:

$ pushd /private/var/tmp/_bazel_pcj/092d6dadaf86f07590903c45033f576e/bazel_testing/bazel_go_test/main
$ bazel build ...