[GN] Add a template which wraps generate_test_lists.py.

chromecast/build/tests/cast_test.gni

+# Copyright 2015 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+# This file contains templates which are meant to simplify building and
+# running test binaries with the Chromecast build infrastructure. See
+# documentation above each template for specific use.
+#
+# Example Usage
+#
+#   # This is a standard test() template from //testing/test.gni. This generates
+#   # a binary called foo_unittests.
+#   test("foo_unittests") {
+#     sources = [ "foo_unittest.cc" ]
+#
+#     deps = [
+#       ":foo",
+#       "//testing/gtest",
+#       "//testing/gmock",
+#     ]
+#   }
+#
+#   # And another standard test() target, which generates bar_unittests
+#   test("bar_unittests") {
+#     sources = [ "bar_unittest.cc" ]
+#
+#     deps = [ ... ]
+#   }
+#
+#   # This is an organizational target. This cannot be built directly.
+#   cast_test_group("cast_tests") {
+#     tests = [
+#       ":bar_unittests",
+#       "//path/to:foo_unittests",
+#     ]
+#   }
+#
+#   # Here is another cast_test_group target which builds a bunch of other
+#   # test binaries, and wants to apply some filters.
+#   cast_test_group("external_tests") {
+#     tests = [
+#       "//path/to/widget:widget_unittests",
+#       "//even/more/foo:foo_unittests",
+#     ]
+#
+#     filters = [
+#       "widget_unittests --gtest_filter=-WidgetTest.TestToBeFiltered",
+#     ]
+#   }
+#
+#   # Build this to create build and run lists for bar and foo tests.
+#   cast_test_group_list("cast_test_lists") {
+#     test_groups = [
+#       ":cast_tests",
+#       ":external_tests",
+#     ]
+#
+#     build_list_paths = "$root_out_dir/path/to/test/build_list.txt"
+#
+#     run_list_path = "$root_out_dir/path/to/list/run_list.txt"
+#   }
+
+import("//testing/test.gni")
+
+# This directory must be the same for every cast_test_group instance.
+_shared_dir = "$root_gen_dir/chromecast/tests"
+
+# A group of test executables. Including test targets in this group makes it
+# possible for Chromecast build infrastructure to build and run them with
+# filters. To accomplish this, it defines two actions, one which generates a
+# build list of all |tests|, and one which generates a run list of all |tests|.
+# It also creates a group with dependencies on each test, to ensure that they
+# are valid targets. Do not build these targets. Build cast_test_group_list
+# instead.
+#
+# Parameters
+#   tests (required)
+#       A list of test targets included in the assembly. Do not include any
+#       other type of target. Each target's name must match the name of the
+#       executable it builds.
+#
+#   filters (optional)
+#       A list of strings of format: "<test_name> --gtest_filter=<filter_logic>"
+#       The <test_name> used must correspond to a test in |tests|. Please see
+#       //chromecast/tools/build/generate_test_lists.py for more information.
+#       If this is not defined, no filters are applied.
+#
+#   priority (optional)
+#       A string which takes any single-digit integer bewtween "1" and "9",
+#       inclusive. Assign this to prioritize filters applied by other
+#       cast_test_groups, where a higher number trumps a lower number.
+#       If not assigned, priority defaults to "1", the lowest priority.
+#
+template("cast_test_group") {
+  assert(defined(invoker.tests),
+         "$target_name needs 'tests' listing the test() targets")
+
+  # If a set of filters has not been defined, use the empty list.
+  _filters = []
+  if (defined(invoker.filters)) {
+    _filters = invoker.filters
+  }
+
+  # If priority has not been set, set the priority to "1", the lowest priority.
+  _priority = "1"
+  if (defined(invoker.priority)) {
+    _priority = invoker.priority
+  }
+
+  # Assert that |_priority| is an integer between "1" and "9", inclusive.
+  assert(_priority == "1" || _priority == "2" || _priority == "3" ||
+         _priority == "4" || _priority == "5" || _priority == "6" ||
+         _priority == "7" || _priority == "8" || _priority == "9")
+
+  # This will be the prefix of each output file.
+  _output_prefix = "$_shared_dir/$_priority-$target_name"
+
+  # Create a list of all the target names. These must correspond to the name of
+  # the test binary.
+  _test_names = []
+  foreach(_test, invoker.tests) {
+    _test_names += [ get_label_info(_test, "name") ]
+  }
+
+  # This action generates a list of target names to build and run. It will be
+  # depended upon by the "pack_build" action of the cast_test_group_list
+  # instance which depends on this cast_test_group.
+  action(target_name + "_create_list") {
+    script = "//chromecast/tools/build/generate_test_lists.py"
+
+    outputs = [
+      "$_output_prefix.tests",
+    ]
+
+    args = [
+      "-o",
+      rebase_path("$_output_prefix.tests"),
+      "create_list",
+    ]
+
+    args += _test_names
+  }
+
+  # This action generates a list of test filters, which will have a priority
+  # [1-9]. This will be depended upon by the "pack_run" action of the
+  # cast_test_group_list which depends on this group.
+  action(target_name + "_filters") {
+    script = "//chromecast/tools/build/generate_test_lists.py"
+
+    outputs = [
+      "$_output_prefix.filters",
+    ]
+
+    args = [
+      "-o",
+      rebase_path("$_output_prefix.filters"),
+      "create_list",
+    ]
+
+    args += _filters
+  }
+
+  # This target allows us to reference each test as a fully-qualified GN path,
+  # to ensure that each path is correct. If a test does not exist, gives a
+  # helpful error message at the line it is included. Do not build this target
+  # directly.
+  group(target_name + "_build_tests") {
+    testonly = true
+    deps = invoker.tests
+  }
+}
+
+# This template runs a script which generates lists of test to be built and run.
+#
+# Parameters
+#   test_groups (required)
+#       The cast_test_group() targets for which this binary is to be created.
+#       The targets referenced here must be cast_test_group targets, or buiding
+#       this target will fail.
+#
+#   build_list_path (required)
+#       The absolute filepath of the output file which will hold the list of
+#       tests to be built.
+#
+#   run_list_path (required)
+#       The absolute filepath of the output file which will hold the list of
+#       tests to be run, each with filters assigned by cast_groups.
+#
+#   additional_options (optional)
+#       Options which are passed to the python script, and applied to every test
+#
+template("cast_test_group_list") {
+  assert(defined(invoker.test_groups), "$target_name needs 'test_groups'")
+  assert(defined(invoker.run_list_path), "$target_name needs 'run_list_path'")
+  assert(defined(invoker.build_list_path),
+         "$target_name needs 'build_list_path'")
+
+  _pack_build_action = target_name + "_pack_build"
+
+  # Generate a list of the "create_list" actions for each group. These will be
+  # depended upon to ensure they're run before the "pack_build" step.
+  _build_actions = []
+  foreach(_test_group, invoker.test_groups) {
+    _build_actions += [ _test_group + "_create_list" ]
+  }
+
+  # Generate a list of the "filter" actions for each group. These will be
+  # depended upon to ensure they're run before the "pack_run" step.
+  _filter_actions = []
+  foreach(_test_group, invoker.test_groups) {
+    _filter_actions += [ _test_group + "_filters" ]
+  }
+
+  # The "pack_build" step. This step looks in the common folder for files with
+  # the ".tests" extenstion, collecting these and packing them into an output
+  # file.  The steps which create these files are depeneded upon, to ensure
+  # they're run before this step. Do not invoke this target directly.
+  action(_pack_build_action) {
+    script = "//chromecast/tools/build/generate_test_lists.py"
+
+    outputs = [
+      invoker.build_list_path,
+    ]
+
+    args = [
+      "-o",
+      rebase_path(invoker.build_list_path),
+      "-t",
+      rebase_path(_shared_dir),
+      "pack_build",
+    ]
+
+    deps = _build_actions
+  }
+
+  # The "pack_run" step. This step looks in the common folder for files with
+  # the ".tests" and ".filters" extensions, creating a script of tests to run,
+  # with filters and priorities. See
+  # //chromecast/tools/build/generate_test_lists.py for more information.
+  # Note that this target takes the name of the invoker, such that invoking the
+  # target runs this step.
+  action(target_name) {
+    script = "//chromecast/tools/build/generate_test_lists.py"
+
+    outputs = [
+      invoker.run_list_path,
+    ]
+
+    args = [
+      "-o",
+      rebase_path(invoker.run_list_path),
+      "-t",
+      rebase_path(_shared_dir),
+      "pack_run",
+    ]
+
+    # Add addtional options if they have been set.
+    if (defined(invoker.additional_options)) {
+      args += [ "-a" ]
+      args += invoker.additional_options
+    }
+
+    # Depend first on the "pack_build" step, so that the build lists are created.
+    deps = [
+      ":$_pack_build_action",
+    ]
+
+    # Next, depend on the filter steps, such that they are created before this
+    # script executes.
+    deps += _filter_actions
+  }
+}