# Copyright 2021 The Chromium Authors
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

# Defines a Rust unit tests group.
#
# This generates a script that wraps 1 or more Rust unit test executables.
# Such script would typically wrap all Rust unit tests from a set of related
# crates (e.g. all crates under //base).
#
# The script is primarily useful to enable running the tests on Chromium bots,
# but it is also a convenience for having a single entry point for running
# the tests locally (without having to manually fan out to all the individual
# executables).
#
# Parameters:
#
#   deps - Will be recursively traversed to discover all the Rust unit test
#          executables.
#
# Example usage:
#
#   # This will generate a script at out/Default/bin/run_foo_tests (or
#   # run_foo_tests.bat on Windows) that wraps the executables containing
#   # native Rust unit tests:
#   # * out/Default/foo_crate1_unittests
#   # * out/Default/foo_mixed_source_set2_rs_unittests
#   # * out/Default/foo_mixed_source_set3_rs_unittests
#   rust_unit_tests_group("foo_tests") {
#     deps = [
#       "foo_crate1",
#       "foo_mixed_source_set2",
#       "foo_mixed_source_set3",
#     ]
#   }

template("rust_unit_tests_group") {
  assert(defined(invoker.deps), "deps must be listed")

  # As noted in the top-level comment of //testing/buildbot/gn_isolate_map.pyl
  # the script *must* be in output_dir/bin/run_$target (or
  # output_dir\bin\run_$target.bat on Windows).
  bat = ""
  if (is_win) {
    bat = ".bat"
  }
  _script_filepath = "$root_out_dir/bin/run_${target_name}${bat}"

  # Gathering metadata provided by the rust_unit_test gni template from all of
  # our dependencies.
  _metadata_target_name = "${target_name}_metadata"
  _metadata_filepath = "$root_build_dir/${target_name}__rust_unittest_exes.txt"
  generated_file(_metadata_target_name) {
    forward_variables_from(invoker, [ "deps" ], [])

    testonly = true
    outputs = [ _metadata_filepath ]
    data_keys = [ "rust_unit_test_executables" ]
  }

  # Generating a script that can run all of the wrapped Rust unit test
  # executables.
  action(target_name) {
    forward_variables_from(invoker, "*", [])

    testonly = true
    script = "//testing/scripts/rust/generate_script.py"
    inputs = [ _metadata_filepath ]
    outputs = [ _script_filepath ]

    data = [ _script_filepath ]

    if (!defined(data_deps)) {
      data_deps = []
    }
    data_deps += [ "//testing/scripts/rust" ]
    data_deps += deps

    deps += [ ":$_metadata_target_name" ]

    args = [
      "--rust-test-executables",
      rebase_path(_metadata_filepath, root_build_dir),
      "--exe-dir",
      rebase_path(root_out_dir, root_build_dir),
      "--script-path",
      rebase_path(_script_filepath, root_build_dir),
    ]
    if (is_win) {
      args += [ "--make-bat" ]
    }
  }
}