Enable passing webdriver binary and args to pytest

This allows us to write some gecko-specific tests for command line argument
handling.

In addition use a file and single environment variable for all the data
we're passing into pytest. Having two separate mechanisms doesn't make
much sense.

Differential Revision: https://phabricator.services.mozilla.com/D134315

bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1732622
gecko-commit: a3f88a74d97c5e27295f52ceefdd5f8f601092cc
gecko-reviewers: webdriver-reviewers, whimboo

Author: jgraham

tools/wptrunner/wptrunner/executors/base.py

@@ -748,9 +748,15 @@ def connect(self):
                           output_handler_start_kwargs=self.output_handler_start_kwargs)
         self.logger.info(
             "WebDriver HTTP server listening at %s" % self.server.url)
-        self.session_config = {"host": self.server.host,
-                               "port": self.server.port,
-                               "capabilities": self.capabilities}
+        self.session_config = {
+            "webdriver": {
+                "binary": self.webdriver_binary,
+                "args": self.webdriver_args
+            },
+            "host": self.server.host,
+            "port": self.server.port,
+            "capabilities": self.capabilities
+        }
 
     def after_connect(self):
         pass

tools/wptrunner/wptrunner/executors/pytestrunner/runner.py

@@ -44,14 +44,14 @@ def run(path, server_config, session_config, timeout=0, environ=None):
     old_environ = os.environ.copy()
     try:
         with TemporaryDirectory() as cache:
-            os.environ["WD_HOST"] = session_config["host"]
-            os.environ["WD_PORT"] = str(session_config["port"])
-            os.environ["WD_CAPABILITIES"] = json.dumps(session_config["capabilities"])
+            config_path = os.path.join(cache, "wd_config.json")
+            os.environ["WDSPEC_CONFIG_FILE"] = config_path
+
+            config = session_config.copy()
+            config["wptserve"] = server_config.as_dict()
 
-            config_path = os.path.join(cache, "wd_server_config.json")
-            os.environ["WD_SERVER_CONFIG_FILE"] = config_path
             with open(config_path, "w") as f:
-                json.dump(server_config.as_dict(), f)
+                json.dump(config, f)
 
             if environ:
                 os.environ.update(environ)

webdriver/tests/support/defaults.py

@@ -4,6 +4,3 @@
 
 WINDOW_POSITION = (100, 100)
 WINDOW_SIZE = (800, 600)
-
-DRIVER_HOST = '127.0.0.1'
-DRIVER_PORT = 4444

webdriver/tests/support/fixtures.py

@@ -59,23 +59,38 @@ def http(configuration):
     return HTTPRequest(configuration["host"], configuration["port"])
 
 
-@pytest.fixture
-def server_config():
-    with open(os.environ.get("WD_SERVER_CONFIG_FILE"), "r") as f:
+@pytest.fixture(scope="session")
+def full_configuration():
+    """Get test configuration information. Keys are:
+
+    host - WebDriver server host.
+    port -  WebDriver server port.
+    capabilites - Capabilites passed when creating the WebDriver session
+    webdriver - Dict with keys `binary`: path to webdriver binary, and
+                `args`: Additional command line arguments passed to the webdriver
+                binary. This doesn't include all the required arguments e.g. the
+                port.
+    wptserve - Configuration of the wptserve servers."""
+
+    with open(os.environ.get("WDSPEC_CONFIG_FILE"), "r") as f:
         return json.load(f)
 
 
 @pytest.fixture(scope="session")
-def configuration():
-    host = os.environ.get("WD_HOST", defaults.DRIVER_HOST)
-    port = int(os.environ.get("WD_PORT", str(defaults.DRIVER_PORT)))
-    capabilities = json.loads(os.environ.get("WD_CAPABILITIES", "{}"))
-
-    return {
-        "host": host,
-        "port": port,
-        "capabilities": capabilities
-    }
+def server_config(full_configuration):
+    return full_configuration["wptserve"]
+
+
+@pytest.fixture(scope="session")
+def configuration(full_configuration):
+    """Configuation minus server config.
+
+    This makes logging easier to read."""
+
+    config = full_configuration.copy()
+    del config["wptserve"]
+
+    return config
 
 
 async def reset_current_session_if_necessary(caps):