fix(errors): Report errors on unknown #[serde(...)] attributes

Closes #51, #175, and #187

serde_macros/tests/compile_tests.rs

@@ -0,0 +1,25 @@
+extern crate compiletest_rs as compiletest;
+
+use std::path::PathBuf;
+use std::env::var;
+
+fn run_mode(mode: &'static str) {
+    let mut config = compiletest::default_config();
+
+    let cfg_mode = mode.parse().ok().expect("Invalid mode");
+
+    config.target_rustcflags = Some("-L target/debug/ -L target/debug/deps/".to_owned());
+    if let Ok(name) = var::<&str>("TESTNAME") {
+        let s : String = name.to_owned();
+        config.filter = Some(s)
+    }
+    config.mode = cfg_mode;
+    config.src_base = PathBuf::from(format!("tests/{}", mode));
+
+    compiletest::run_tests(&config);
+}
+
+#[test]
+fn compile_test() {
+    run_mode("compile-fail");
+}