[wptrunner] Split message-queue.js from testharnessreport.js

This will allow non-testharness tests to use `testdriver.js` without
needing extra scripts. Evaluating `message-queue.js` is idempotent so
that, when using testharness with testdriver, the second inclusion is a
no-op.

Because resource scripts are cached, the size increase should not
meaningfully affect test performance.

tools/wptrunner/wptrunner/environment.py

@@ -23,8 +23,6 @@
 sys.path.insert(0, repo_root)
 from tools import localpaths  # noqa: F401
 
-from wptserve.handlers import StringHandler
-
 serve = None
 
 
@@ -225,29 +223,47 @@ def get_routes(self):
             self.config.aliases,
             self.config)
 
+        testharnessreport_format_args = {
+            "output": self.pause_after_test,
+            "timeout_multiplier": self.testharness_timeout_multipler,
+            "explicit_timeout": "true" if self.debug_info is not None else "false",
+            "debug": "true" if self.debug_test else "false",
+        }
         for path, format_args, content_type, route in [
                 ("testharness_runner.html", {}, "text/html", "/testharness_runner.html"),
                 ("print_pdf_runner.html", {}, "text/html", "/print_pdf_runner.html"),
-                (os.path.join(here, "..", "..", "third_party", "pdf_js", "pdf.js"), None,
+                (os.path.join(here, "..", "..", "third_party", "pdf_js", "pdf.js"), {},
                  "text/javascript", "/_pdf_js/pdf.js"),
-                (os.path.join(here, "..", "..", "third_party", "pdf_js", "pdf.worker.js"), None,
+                (os.path.join(here, "..", "..", "third_party", "pdf_js", "pdf.worker.js"), {},
                  "text/javascript", "/_pdf_js/pdf.worker.js"),
-                (self.options.get("testharnessreport", "testharnessreport.js"),
-                 {"output": self.pause_after_test,
-                  "timeout_multiplier": self.testharness_timeout_multipler,
-                  "explicit_timeout": "true" if self.debug_info is not None else "false",
-                  "debug": "true" if self.debug_test else "false"},
-                 "text/javascript;charset=utf8",
-                 "/resources/testharnessreport.js")]:
-            path = os.path.normpath(os.path.join(here, path))
+                (
+                    self.options.get("testharnessreport", [
+                        # All testharness tests, even those that don't use testdriver, require
+                        # `message-queue.js` to signal completion.
+                        os.path.join("executors", "message-queue.js"),
+                        "testharnessreport.js"]),
+                    testharnessreport_format_args,
+                    "text/javascript;charset=utf8",
+                    "/resources/testharnessreport.js",
+                ),
+                (
+                    [os.path.join(repo_root, "resources", "testdriver.js"),
+                     # Include `message-queue.js` to support testdriver in non-testharness tests.
+                     os.path.join("executors", "message-queue.js"),
+                     "testdriver-extra.js"],
+                    {},
+                    "text/javascript",
+                    "/resources/testdriver.js",
+                ),
+        ]:
+            paths = [path] if isinstance(path, str) else path
+            abs_paths = [os.path.normpath(os.path.join(here, path)) for path in paths]
             # Note that .headers. files don't apply to static routes, so we need to
             # readd any static headers here.
             headers = {"Cache-Control": "max-age=3600"}
-            route_builder.add_static(path, format_args, content_type, route,
+            route_builder.add_static(abs_paths, format_args, content_type, route,
                                      headers=headers)
 
-        route_builder.add_handler("GET", "/resources/testdriver.js", TestdriverLoader())
-
         for url_base, test_root in self.test_paths.items():
             if url_base == "/":
                 continue
@@ -315,27 +331,6 @@ def test_servers(self):
         return failed, pending
 
 
-class TestdriverLoader:
-    """A special static handler for serving `/resources/testdriver.js`.
-
-    This handler lazily reads `testdriver{,-extra}.js` so that wptrunner doesn't
-    need to pass the entire file contents to child `wptserve` processes, which
-    can slow `wptserve` startup by several seconds (crbug.com/1479850).
-    """
-    def __init__(self):
-        self._handler = None
-
-    def __call__(self, request, response):
-        if not self._handler:
-            data = b""
-            with open(os.path.join(repo_root, "resources", "testdriver.js"), "rb") as fp:
-                data += fp.read()
-            with open(os.path.join(here, "testdriver-extra.js"), "rb") as fp:
-                data += fp.read()
-            self._handler = StringHandler(data, "text/javascript")
-        return self._handler(request, response)
-
-
 def wait_for_service(logger: StructuredLogger,
                      host: str,
                      port: int,

tools/wptrunner/wptrunner/executors/message-queue.js

@@ -0,0 +1,77 @@
+(function() {
+  if (window.__wptrunner_message_queue && window.__wptrunner_process_next_event) {
+    // Another script already set up the testdriver infrastructure.
+    return;
+  }
+
+  class MessageQueue {
+    constructor() {
+      this.item_id = 0;
+      this._queue = [];
+    }
+
+    push(item) {
+      let cmd_id = this.item_id++;
+      item.id = cmd_id;
+      this._queue.push(item);
+      __wptrunner_process_next_event();
+      return cmd_id;
+    }
+
+    shift() {
+      return this._queue.shift();
+    }
+  }
+
+  window.__wptrunner_testdriver_callback = null;
+  window.__wptrunner_message_queue = new MessageQueue();
+  window.__wptrunner_url = null;
+
+  window.__wptrunner_process_next_event = function() {
+    /* This function handles the next testdriver event. The presence of
+       window.testdriver_callback is used as a switch; when that function
+       is present we are able to handle the next event and when is is not
+       present we must wait. Therefore to drive the event processing, this
+       function must be called in two circumstances:
+         * Every time there is a new event that we may be able to handle
+         * Every time we set the callback function
+       This function unsets the callback, so no further testdriver actions
+       will be run until it is reset, which wptrunner does after it has
+       completed handling the current action.
+     */
+
+    if (!window.__wptrunner_testdriver_callback) {
+      return;
+    }
+    var data = window.__wptrunner_message_queue.shift();
+    if (!data) {
+      return;
+    }
+
+    var payload = undefined;
+
+    switch(data.type) {
+    case "complete":
+      var tests = data.tests;
+      var status = data.status;
+
+      var subtest_results = tests.map(function(x) {
+        return [x.name, x.status, x.message, x.stack];
+      });
+      payload = [status.status,
+                 status.message,
+                 status.stack,
+                 subtest_results];
+      clearTimeout(window.__wptrunner_timer);
+      break;
+    case "action":
+      payload = data;
+      break;
+    default:
+      return;
+    }
+    var callback = window.__wptrunner_testdriver_callback;
+    window.__wptrunner_testdriver_callback = null;
+    callback([__wptrunner_url, data.type, payload]);
+  };
+})();

tools/wptrunner/wptrunner/testdriver-extra.js

@@ -59,7 +59,7 @@
     });
 
     function is_test_context() {
-      return window.__wptrunner_message_queue !== undefined;
+      return !!window.__wptrunner_is_test_context;
     }
 
     // Code copied from /common/utils.js
@@ -226,7 +226,7 @@
     };
 
     window.test_driver_internal.set_test_context = function(context) {
-        if (window.__wptrunner_message_queue) {
+        if (is_test_context()) {
             throw new Error("Tried to set testharness context in a window containing testharness.js");
         }
         testharness_context = context;

tools/wptrunner/wptrunner/testharnessreport.js

@@ -1,75 +1,9 @@
-class MessageQueue {
-  constructor() {
-    this.item_id = 0;
-    this._queue = [];
-  }
-
-  push(item) {
-    let cmd_id = this.item_id++;
-    item.id = cmd_id;
-    this._queue.push(item);
-    __wptrunner_process_next_event();
-    return cmd_id;
-  }
-
-  shift() {
-    return this._queue.shift();
-  }
-}
-
-window.__wptrunner_testdriver_callback = null;
-window.__wptrunner_message_queue = new MessageQueue();
-window.__wptrunner_url = null;
-
-window.__wptrunner_process_next_event = function() {
-  /* This function handles the next testdriver event. The presence of
-     window.testdriver_callback is used as a switch; when that function
-     is present we are able to handle the next event and when is is not
-     present we must wait. Therefore to drive the event processing, this
-     function must be called in two circumstances:
-       * Every time there is a new event that we may be able to handle
-       * Every time we set the callback function
-     This function unsets the callback, so no further testdriver actions
-     will be run until it is reset, which wptrunner does after it has
-     completed handling the current action.
-   */
-
-  if (!window.__wptrunner_testdriver_callback) {
-    return;
-  }
-  var data = window.__wptrunner_message_queue.shift();
-  if (!data) {
-    return;
-  }
-
-  var payload = undefined;
-
-  switch(data.type) {
-  case "complete":
-    var tests = data.tests;
-    var status = data.status;
-
-    var subtest_results = tests.map(function(x) {
-      return [x.name, x.status, x.message, x.stack];
-    });
-    payload = [status.status,
-               status.message,
-               status.stack,
-               subtest_results];
-    clearTimeout(window.__wptrunner_timer);
-    break;
-  case "action":
-    payload = data;
-    break;
-  default:
-    return;
-  }
-  var callback = window.__wptrunner_testdriver_callback;
-  window.__wptrunner_testdriver_callback = null;
-  callback([__wptrunner_url, data.type, payload]);
-};
-
 (function() {
+  // Signal to `testdriver.js` that this is the "main" test browsing context,
+  // meaning testdriver actions should be queued for retrieval instead of
+  // `postMessage()`d elsewhere.
+  window.__wptrunner_is_test_context = true;
+
   var props = {output: %(output)d,
                timeout_multiplier: %(timeout_multiplier)s,
                explicit_timeout: %(explicit_timeout)s,
@@ -85,4 +19,3 @@ window.__wptrunner_process_next_event = function() {
   });
   setup(props);
 })();
-

tools/wptserve/wptserve/handlers.py

@@ -513,19 +513,21 @@ def __init__(self, path, format_args, content_type, **headers):
 
         Note that *.headers files have no effect in this handler.
 
-        :param path: Path to the template file to use
+        :param path: Path(s) to template files to use. If a sequence of paths is provided instead
+            of a single path, the contents of each file will be concatenated together before the
+            `format_args` are interpolated.
         :param format_args: Dictionary of values to substitute into the template file
         :param content_type: Content type header to server the response with
         :param headers: List of headers to send with responses"""
-        self._path = path
+        self._paths = [path] if isinstance(path, str) else path
         self._format_args = format_args
         self._content_type = content_type
         self._headers = headers
         self._handler = None
 
     def __getnewargs_ex__(self):
         # Do not pickle `self._handler`, which can be arbitrarily large.
-        args = self._path, self._format_args, self._content_type
+        args = self._paths, self._format_args, self._content_type
         return args, self._headers
 
     def __call__(self, request, response):
@@ -534,8 +536,10 @@ def __call__(self, request, response):
         # contents across processes can slow `wptserve` startup by several
         # seconds (crbug.com/1479850).
         if not self._handler:
-            with open(self._path) as f:
-                data = f.read()
+            data = ""
+            for path in self._paths:
+                with open(path) as f:
+                    data += f.read()
             if self._format_args:
                 data = data % self._format_args
             self._handler = StringHandler(data, self._content_type, **self._headers)