Auto merge of #13415 - Manishearth:style-testing-disable, r=SimonSapin

Run style unit tests in testing mode, disable some properties in testing mode

Another crack at making it possible to test geckolib properties.

In the previous PR I added support for a testing mode but neglected to use it in the style unit tests.

Using it brought out some bugs with properties that exist in both gecko and servo but have different names. Added the ability to disable them.

Hopefully this isn't too unweildy.

r? @emilio

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python/servo/testing_commands.py

@@ -220,14 +220,11 @@ class MachCommands(CommandBase):
 
         packages.discard('stylo')
 
-        args = ["cargo", "test"]
-        for crate in packages:
-            args += ["-p", "%s_tests" % crate]
-        args += test_patterns
-
-        features = self.servo_features()
-        if features:
-            args += ["--features", "%s" % ' '.join(features)]
+        has_style = True
+        try:
+            packages.remove('style')
+        except KeyError:
+            has_style = False
 
         env = self.build_env()
         env["RUST_BACKTRACE"] = "1"
@@ -240,9 +237,29 @@ class MachCommands(CommandBase):
             else:
                 env["RUSTFLAGS"] = "-C link-args=-Wl,--subsystem,windows"
 
-        result = call(args, env=env, cwd=self.servo_crate())
-        if result != 0:
-            return result
+        features = self.servo_features()
+        if len(packages) > 0:
+            args = ["cargo", "test"]
+            for crate in packages:
+                args += ["-p", "%s_tests" % crate]
+            args += test_patterns
+
+            if features:
+                args += ["--features", "%s" % ' '.join(features)]
+            result = call(args, env=env, cwd=self.servo_crate())
+            if result != 0:
+                return result
+
+        # Run style tests with the testing feature
+        if has_style:
+            args = ["cargo", "test", "-p", "style_tests", "--features"]
+            if features:
+                args += ["%s" % ' '.join(features + ["testing"])]
+            else:
+                args += ["testing"]
+            result = call(args, env=env, cwd=self.servo_crate())
+            if result != 0:
+                return result
 
     @Command('test-stylo',
              description='Run stylo unit tests',