Add expectations.txt validation to presubmit

Change-Id: Ibabdfbdf44b027a6e6441e140f23b2c2488f32dc
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/112120
Reviewed-by: Ben Clayton <bclayton@google.com>
Commit-Queue: Austin Eng <enga@chromium.org>
Kokoro: Kokoro <noreply+kokoro@google.com>
diff --git a/go_presubmit_support.py b/go_presubmit_support.py
index f456355..83988c0 100644
--- a/go_presubmit_support.py
+++ b/go_presubmit_support.py
@@ -12,17 +12,24 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+
+def go_path(input_api):
+    go = input_api.os_path.join(input_api.change.RepositoryRoot(), "tools",
+                                "golang", "bin", "go")
+    if input_api.is_windows:
+        go += '.exe'
+
+    return go
+
+
 def RunGoTests(input_api, output_api):
     results = []
     try:
-        go = input_api.os_path.join(input_api.change.RepositoryRoot(), "tools",
-                                    "golang", "bin", "go")
-        if input_api.is_windows:
-            go += '.exe'
-        input_api.subprocess.check_call_out([go, "test", "./..."],
-                                            stdout=input_api.subprocess.PIPE,
-                                            stderr=input_api.subprocess.PIPE,
-                                            cwd=input_api.PresubmitLocalPath())
+        input_api.subprocess.check_call_out(
+            [go_path(input_api), "test", "./..."],
+            stdout=input_api.subprocess.PIPE,
+            stderr=input_api.subprocess.PIPE,
+            cwd=input_api.PresubmitLocalPath())
     except input_api.subprocess.CalledProcessError as e:
         results.append(output_api.PresubmitError('%s' % (e, )))
     return results
diff --git a/webgpu-cts/PRESUBMIT.py b/webgpu-cts/PRESUBMIT.py
new file mode 100644
index 0000000..1280d5c
--- /dev/null
+++ b/webgpu-cts/PRESUBMIT.py
@@ -0,0 +1,53 @@
+# Copyright 2022 The Dawn & Tint Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import sys
+
+USE_PYTHON3 = True
+
+
+def _DoCommonChecks(input_api, output_api):
+    sys.path += [input_api.change.RepositoryRoot()]
+
+    from go_presubmit_support import go_path
+
+    results = []
+    try:
+        tools_path = input_api.os_path.join(input_api.change.RepositoryRoot(),
+                                            'tools')
+        cts_bin = input_api.os_path.join(tools_path, 'bin', 'cts')
+
+        cmd = [
+            go_path(input_api), 'build', '-o', cts_bin,
+            input_api.os_path.join('.', 'cmd', 'cts')
+        ]
+        input_api.subprocess.check_call_out(cmd,
+                                            stdout=input_api.subprocess.PIPE,
+                                            stderr=input_api.subprocess.PIPE,
+                                            cwd=input_api.os_path.join(
+                                                tools_path, 'src'))
+
+        cmd = [cts_bin, 'validate']
+        input_api.subprocess.check_call_out(
+            cmd,
+            stdout=input_api.subprocess.PIPE,
+            stderr=input_api.subprocess.PIPE,
+            cwd=input_api.change.RepositoryRoot())
+    except input_api.subprocess.CalledProcessError as e:
+        results.append(output_api.PresubmitError('%s' % (e, )))
+    return results
+
+
+CheckChangeOnUpload = _DoCommonChecks
+CheckChangeOnCommit = _DoCommonChecks