1 files changed, 49 insertions, 0 deletions
diff --git a/servo/tests/unit/style/custom_properties.rs b/servo/tests/unit/style/custom_properties.rs
new file mode 100644
index 0000000000..b24ca3b132
--- /dev/null
+++ b/servo/tests/unit/style/custom_properties.rs
@@ -0,0 +1,49 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+use cssparser::{Parser, ParserInput};
+use servo_arc::Arc;
+use style::custom_properties::{
+    CssEnvironment, CustomPropertiesBuilder, CustomPropertiesMap, Name, SpecifiedValue,
+};
+use style::properties::CustomDeclarationValue;
+use test::{self, Bencher};
+
+fn cascade(
+    name_and_value: &[(&str, &str)],
+    inherited: Option<&Arc<CustomPropertiesMap>>,
+) -> Option<Arc<CustomPropertiesMap>> {
+    let values = name_and_value
+        .iter()
+        .map(|&(name, value)| {
+            let mut input = ParserInput::new(value);
+            let mut parser = Parser::new(&mut input);
+            (
+                Name::from(name),
+                SpecifiedValue::parse(&mut parser).unwrap(),
+            )
+        })
+        .collect::<Vec<_>>();
+
+    let env = CssEnvironment;
+    let mut builder = CustomPropertiesBuilder::new(inherited, &env);
+
+    for &(ref name, ref val) in &values {
+        builder.cascade(name, &CustomDeclarationValue::Value(val.clone()));
+    }
+
+    builder.build()
+}
+
+#[bench]
+fn cascade_custom_simple(b: &mut Bencher) {
+    b.iter(|| {
+        let parent = cascade(&[("foo", "10px"), ("bar", "100px")], None);
+
+        test::black_box(cascade(
+            &[("baz", "calc(40em + 4px)"), ("bazz", "calc(30em + 4px)")],
+            parent.as_ref(),
+        ))
+    })
+}