Make css-properties.json checking a proper unit test.

tests/unit/style/Cargo.toml

@@ -30,3 +30,4 @@ euclid = {version = "0.6.4", features = ["plugins"]}
 selectors = {version = "0.5", features = ["heap_size"]}
 string_cache = {version = "0.2.12", features = ["heap_size"]}
 url = {version = "1.0.0", features = ["heap_size"]}
+rustc-serialize = "0.3"

tests/unit/style/lib.rs

@@ -10,6 +10,7 @@ extern crate app_units;
 extern crate cssparser;
 extern crate euclid;
 extern crate msg;
+extern crate rustc_serialize;
 extern crate selectors;
 #[macro_use(atom, ns)] extern crate string_cache;
 extern crate style;
@@ -20,6 +21,7 @@ extern crate util;
 #[cfg(test)] mod attr;
 #[cfg(test)] mod logical_geometry;
 #[cfg(test)] mod media_queries;
+#[cfg(test)] mod properties;
 #[cfg(test)] mod stylesheets;
 #[cfg(test)] mod viewport;
 

tests/unit/style/properties.rs

@@ -0,0 +1,53 @@
+/* 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 http://mozilla.org/MPL/2.0/. */
+
+use rustc_serialize::json::Json;
+use std::env;
+use std::fs::{File, remove_file};
+use std::path::Path;
+use std::process::Command;
+
+#[test]
+fn properties_list_json() {
+    let top = Path::new(file!()).parent().unwrap().join("..").join("..").join("..");
+    let json = top.join("target").join("doc").join("servo").join("css-properties.json");
+    if json.exists() {
+        remove_file(&json).unwrap()
+    }
+    let python = env::var("PYTHON").ok().unwrap_or_else(find_python);
+    let script = top.join("components").join("style").join("properties").join("build.py");
+    let status = Command::new(python)
+        .arg(&script)
+        .arg("servo")
+        .arg("html")
+        .status()
+        .unwrap();
+    assert!(status.success());
+    let properties = Json::from_reader(&mut File::open(json).unwrap()).unwrap();
+    assert!(properties.as_object().unwrap().len() > 100);
+    assert!(properties.find("margin").is_some());
+    assert!(properties.find("margin-top").is_some());
+}
+
+#[cfg(windows)]
+fn find_python() -> String {
+    if Command::new("python27.exe").arg("--version").output().is_ok() {
+        return "python27.exe".to_owned();
+    }
+
+    if Command::new("python.exe").arg("--version").output().is_ok() {
+        return "python.exe".to_owned();
+    }
+
+    panic!("Can't find python (tried python27.exe and python.exe)! Try fixing PATH or setting the PYTHON env var");
+}
+
+#[cfg(not(windows))]
+fn find_python() -> String {
+    if Command::new("python2.7").arg("--version").output().unwrap().status.success() {
+        "python2.7"
+    } else {
+        "python"
+    }.to_owned()
+}