# Copyright 2020 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

# Declares host-side test data and makes them available at test runtime.
#
# It is a requirement that host tests with runtime dependencies express this
# by depending on instances of this template.
#
# Parameters
#
#   * sources
#     - Required: Sources to serve as host test data.
#     - Type: list(path)
#
#   * outputs
#     - Optional: Where to copy the provided sources. If provided, these
#       locations (and not those of sources) will be declared as runtime
#       dependencies.
#     - Type: list(path relative to $root_build_dir)
#
#   * deps
#   * visibility
#     - Optional: Usual GN meanings.
#
if (is_host) {
  template("host_test_data") {
    testonly = true
    assert(defined(invoker.sources), "sources are required")

    main_target_name = target_name
    if (defined(invoker.outputs)) {
      metadata_target_name = "${target_name}_metadata"

      # The main target that copies test data to the build directory.
      # It depends on the generated group `group_target_name`, which
      # carries the `test_runtime_deps` metadata.
      # The copy rule is the main target so that clients can still
      # call `get_target_outputs` on it.
      copy(main_target_name) {
        forward_variables_from(invoker, "*")
        if (!defined(deps)) {
          deps = []
        }
        deps += [ ":$metadata_target_name" ]
      }
      test_data = get_target_outputs(":$main_target_name")
    } else {
      metadata_target_name = main_target_name

      # In this case, all provided sources should lie within the build
      # directory.
      foreach(source, invoker.sources) {
        in_build_dir =
            get_path_info(rebase_path(source, root_build_dir), "dir") != ".."
        assert(
            in_build_dir,
            "$source must be within the build directory to be declared as test data")
      }
      test_data = invoker.sources
    }

    # This group exists only to carry the `test_runtime_deps` metadata, which
    # is aggregated by test_spec().
    group(metadata_target_name) {
      forward_variables_from(invoker, [ "deps" ])
      metadata = {
        test_runtime_deps = test_data
      }
    }
  }
}