Add unit test crate for stylo

ports/geckolib/Cargo.lock

@@ -14,6 +14,7 @@ dependencies = [
  "selectors 0.13.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "style 0.0.1",
  "style_traits 0.0.1",
+ "stylo_tests 0.0.1",
  "url 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -52,6 +53,7 @@ version = "0.7.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "encoding 0.2.33 (registry+https://github.com/rust-lang/crates.io-index)",
+ "heapsize 0.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
  "matches 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -393,6 +395,16 @@ dependencies = [
  "rustc-serialize 0.3.19 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "stylo_tests"
+version = "0.0.1"
+dependencies = [
+ "app_units 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cssparser 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "style 0.0.1",
+ "style_traits 0.0.1",
+]
+
 [[package]]
 name = "thread-id"
 version = "2.0.0"

ports/geckolib/Cargo.toml

@@ -23,3 +23,6 @@ selectors = "0.13"
 style = {path = "../../components/style", features = ["gecko"]}
 style_traits = {path = "../../components/style_traits"}
 url = "1.2"
+
+[dev-dependencies]
+stylo_tests = {path = "../../tests/unit/stylo"}

python/servo/testing_commands.py

@@ -25,7 +25,7 @@ from mach.decorators import (
     Command,
 )
 
-from servo.command_base import CommandBase, call, check_call, host_triple
+from servo.command_base import CommandBase, call, cd, check_call, host_triple
 from wptrunner import wptcommandline
 from update import updatecommandline
 from servo_tidy import tidy
@@ -232,6 +232,26 @@ class MachCommands(CommandBase):
         if result != 0:
             return result
 
+    @Command('test-stylo',
+             description='Run stylo unit tests',
+             category='testing')
+    def test_unit(self, test_name=None, package=None):
+        if test_name is None:
+            test_name = []
+
+        self.set_use_stable_rust()
+        self.ensure_bootstrapped()
+
+        env = self.build_env()
+        env["RUST_BACKTRACE"] = "1"
+        env["CARGO_TARGET_DIR"] = path.join(self.context.topdir, "target", "geckolib").encode("UTF-8")
+
+        with cd(path.join("ports", "geckolib")):
+            result = call(["cargo", "test", "-p", "stylo_tests"], env=env)
+
+        if result != 0:
+            return result
+
     @Command('test-compiletest',
              description='Run compiletests',
              category='testing')

tests/unit/stylo/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+name = "stylo_tests"
+version = "0.0.1"
+authors = ["The Servo Project Developers"]
+license = "MPL-2.0"
+
+[lib]
+name = "stylo_tests"
+path = "lib.rs"
+doctest = false
+
+[dependencies]
+app_units = "0.3"
+cssparser = {version = "0.7", features = ["heap_size"]}
+style = {path = "../../../components/style", features = ["gecko"]}
+style_traits = {path = "../../../components/style_traits"}

tests/unit/stylo/lib.rs

@@ -0,0 +1,10 @@
+extern crate app_units;
+extern crate cssparser;
+extern crate style;
+extern crate style_traits;
+
+#[test]
+fn test_test() {
+    // do nothing
+    // this is a temporary test testing that the test runs
+}