Add no-compile test support to GN build

build/nocompile.gni

 # Copyright (c) 2011 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 is meant to be included into an target to create a unittest that
 # invokes a set of no-compile tests.  A no-compile test is a test that asserts
 # a particular construct will not compile.
 #
 # Also see:
 #   http://dev.chromium.org/developers/testing/no-compile-tests
 #
 # To use this, create a gyp target with the following form:
-# {
-#   'target_name': 'my_module_nc_unittests',
-#   'type': 'executable',
-#   'sources': [
+#
+# import("//build/nocompile.gni")
+# nocompile_test("my_module_nc_unittests") {
+#   sources = [
 #     'nc_testset_1.nc',
 #     'nc_testset_2.nc',
-#   ],
-#   'includes': ['path/to/this/gypi/file'],
+#   ]
 # }
 #
 # The .nc files are C++ files that contain code we wish to assert will not
 # compile.  Each individual test case in the file should be put in its own
 # #ifdef section.  The expected output should be appended with a C++-style
 # comment that has a python list of regular expressions.  This will likely
 # be greater than 80-characters. Giving a solid expected output test is
 # important so that random compile failures do not cause the test to pass.
 #
 # Example .nc file:
@@ skipping 18 matching lines @@
 # formatting or ifdef logic; it will likely just not work.
 #
 # Implementation notes:
 # The .nc files are actually processed by a python script which executes the
 # compiler and generates a .cc file that is empty on success, or will have a
 # series of #error lines on failure, and a set of trivially passing gunit
 # TEST() functions on success. This allows us to fail at the compile step when
 # something goes wrong, and know during the unittest run that the test was at
 # least processed when things go right.
 
-{
-  # TODO(awong): Disabled until http://crbug.com/105388 is resolved.
-  'sources/': [['exclude', '\\.nc$']],
-  'conditions': [
-    [ 'OS!="win" and clang==1', {
-      'rules': [
-        {
-          'variables': {
-            'nocompile_driver': '<(DEPTH)/tools/nocompile_driver.py',
-            'nc_result_path': ('<(INTERMEDIATE_DIR)/<(module_dir)/'
-                               '<(RULE_INPUT_ROOT)_nc.cc'),
-           },
-          'rule_name': 'run_nocompile',
-          'extension': 'nc',
-          'inputs': [
-            '<(nocompile_driver)',
-          ],
-          'outputs': [
-            '<(nc_result_path)'
-          ],
-          'action': [
-            'python',
-            '<(nocompile_driver)',
-            '4', # number of compilers to invoke in parallel.
-            '<(RULE_INPUT_PATH)',
-            '-Wall -Werror -Wfatal-errors -I<(DEPTH)',
-            '<(nc_result_path)',
-            ],
-          'message': 'Generating no compile results for <(RULE_INPUT_PATH)',
-          'process_outputs_as_sources': 1,
-        },
-      ],
-    }, {
-      'sources/': [['exclude', '\\.nc$']]
-    }],  # 'OS!="win" and clang=="1"'
-  ],
+import("//testing/test.gni")
+
+declare_args() {
+  enable_nocompile_tests = false
 }
 
+if (enable_nocompile_tests) {
+  template("nocompile_test") {
+    nocompile_target = target_name + "_run_nocompile"
+
+    action_foreach(nocompile_target) {
+      script = "//tools/nocompile_driver.py"
+      sources = invoker.sources
+      outputs = [
+        "$target_gen_dir/{{source_name_part}}_nc.cc",
+      ]
+      args = [
+        "4",

[dcheng, 2015/12/15 18:14:47]

I'm not very familiar with GN: what does the 4 here mean?

[Nico, 2015/12/15 19:10:04]

See this on the lhs:

'4', # number of compilers to invoke in parallel.

It's just passed through literally. (see also `gn help action_forach`). Maybe a
comment saying "# Number of parallel compiles" on the rhs would be good too.

[tzik, 2015/12/16 07:45:27]

Added the comment too.
Yes, it's from the .gypi.

+        "{{source}}",
+        "-Wall -Werror -Wfatal-errors " + "-I" +
+            rebase_path("//", root_build_dir),
+        "{{output}}",
+      ]
+    }
+
+    test(target_name) {
+      deps = invoker.deps + [ ":$nocompile_target" ]
+      sources = get_target_outputs(":$nocompile_target")
+    }
+  }
+}