Bug 1505474 - Use downloaded manifest for wpt in jsshell, r=bbouvier,Ms2ger

web-platform-tests gets its test list from a manifest file that's
generated from the content of the tests. Unfortunately generating this
manifest is slow, so it's unreasonable to create it from scratch for
every test run. Until recently the generated manifest was kept
in-tree, which was suboptimal in a few ways:

* The manifest tended to get out of sync with the actual source
* The large json file caused problems for tooling including source
  control and the review frontends.

We previously switched `mach wpt` to download a manifest on demand and
apply an incremental update. However this work missed the usage in
jstests.py. This continued to use the increasing outdated in-tree
manifest, which causes a number of problems

* It doesn't have an up-to-date list of tests
* It blocks removing that file
* It blocks landing various optimisations to make updating the
  manifest faster.

This patch fixes jstests.py to use a downloaded manifest. Unlike the
tests run through a mach frontend jstests.py doesn't know where the
objdir is, so it's hard to work out where to download the
manifest. This patch adopts a heuristic approach; if the path to the
jsshell looks like <root>/dist/bin and <root>/_tests exists, we assume
it's a gecko-like objdir and use <root>/_tests/web-platform/ for the
manifest; otherwise we just put it into the system tempdir.

Because the manifest has to be updated on startup, this patch causes a
startup time regression, but this will be considerably reduced by the
work in Bug 1497898 for which this is a prerequisite.

Differential Revision: https://phabricator.services.mozilla.com/D11667

--HG--
extra : moz-landing-system : lando

js/src/tests/jstests.py

@@ -13,6 +13,7 @@ from __future__ import print_function
 
 import os
 import sys
+import tempfile
 import textwrap
 import platform
 from os.path import abspath, dirname, isfile, realpath
@@ -295,7 +296,7 @@ def parse_args():
     return (options, prefix, requested_paths, excluded_paths)
 
 
-def load_wpt_tests(requested_paths, excluded_paths, debug, wasm):
+def load_wpt_tests(xul_tester, requested_paths, excluded_paths):
     """Return a list of `RefTestCase` objects for the jsshell testharness.js
     tests filtered by the given paths and debug-ness."""
     repo_root = abspath(os.path.join(here, "..", "..", ".."))
@@ -313,6 +314,7 @@ def load_wpt_tests(requested_paths, excluded_paths, debug, wasm):
         "testing/mozbase/mozprocess",
         "testing/mozbase/mozprofile",
         "testing/mozbase/mozrunner",
+        "testing/web-platform/",
         "testing/web-platform/tests/tools",
         "testing/web-platform/tests/tools/third_party/html5lib",
         "testing/web-platform/tests/tools/third_party/webencodings",
@@ -331,17 +333,28 @@ def load_wpt_tests(requested_paths, excluded_paths, debug, wasm):
 
     sys.path[0:0] = abs_sys_paths
 
+    import manifestupdate
     from wptrunner import products, testloader, wptcommandline, wpttest, wptlogging
 
-    wptlogging.setup({}, {})
-    kwargs = {
-        "config": None,
-        "tests_root": wpt,
-        "metadata_root": os.path.join(wp, "meta"),
+    manifest_root = tempfile.gettempdir()
+    path_split = os.path.dirname(xul_tester.js_bin).split(os.path.sep)
+    if path_split[-2:] == ["dist", "bin"]:
+        maybe_root = os.path.join(*path_split[:-2])
+        if os.path.exists(os.path.join(maybe_root, "_tests")):
+            # Assume this is a gecko objdir.
+            manifest_root = maybe_root
+
+    logger = wptlogging.setup({}, {})
+
+    manifestupdate.run(repo_root, manifest_root, logger)
+
+    kwargs = vars(wptcommandline.create_parser().parse_args([]))
+    kwargs.update({
+        "config": os.path.join(manifest_root, "_tests", "web-platform", "wptrunner.local.ini"),
         "gecko_e10s": False,
         "verify": False,
-        "wasm": wasm,
-    }
+        "wasm": xul_tester.test("wasmIsSupported()"),
+    })
     wptcommandline.set_from_config(kwargs)
     test_paths = kwargs["test_paths"]
 
@@ -354,8 +367,10 @@ def load_wpt_tests(requested_paths, excluded_paths, debug, wasm):
                                                meta_filters=[filter_jsshell_tests]).load()
 
     run_info_extras = products.load_product(kwargs["config"], "firefox")[-1](**kwargs)
-    run_info = wpttest.get_run_info(kwargs["metadata_root"], "firefox",
-                                    debug=debug, extras=run_info_extras)
+    run_info = wpttest.get_run_info(kwargs["test_paths"]["/"]["metadata_path"],
+                                    "firefox",
+                                    debug=xul_tester.test("isDebugBuild"),
+                                    extras=run_info_extras)
 
     path_filter = testloader.TestFilter(test_manifests,
                                         include=requested_paths,
@@ -415,9 +430,9 @@ def load_tests(options, requested_paths, excluded_paths):
 
     # WPT tests are already run in the browser in their own harness.
     if not options.make_manifests:
-        wpt_tests = load_wpt_tests(requested_paths, excluded_paths,
-                                   debug=xul_tester.test("isDebugBuild"),
-                                   wasm=xul_tester.test("wasmIsSupported()"))
+        wpt_tests = load_wpt_tests(xul_tester,
+                                   requested_paths,
+                                   excluded_paths)
         test_count += len(wpt_tests)
         test_gen = chain(test_gen, wpt_tests)