tests(readme): Use skeptic to test the readme

serde_macros/Cargo.toml

@@ -8,17 +8,27 @@ repository = "https://github.com/serde-rs/serde"
 documentation = "https://github.com/serde-rs/serde"
 keywords = ["serde", "serialization"]
 include = ["Cargo.toml", "src/**/*.rs"]
+build = "build.rs"
 
 [lib]
 name = "serde_macros"
 plugin = true
 
 [features]
-unstable-testing = ["clippy", "serde/unstable-testing", "serde_codegen/unstable-testing"]
+unstable-testing = [
+    "clippy",
+    "skeptic",
+    "serde/unstable-testing",
+    "serde_codegen/unstable-testing"
+]
+
+[build-dependencies]
+skeptic = { version = "^0.6.0", optional = true }
 
 [dependencies]
 clippy = { version = "^0.*", optional = true }
 serde_codegen = { version = "=0.8.0", default-features = false, features = ["unstable"] }
+skeptic = { version = "^0.6.0", optional = true }
 
 [dev-dependencies]
 clippy = "^0.*"

serde_macros/build.rs

@@ -0,0 +1,17 @@
+#[cfg(feature = "nightly-testing")]
+mod inner {
+    extern crate skeptic;
+
+    pub fn main() {
+        skeptic::generate_doc_tests(&["../README.md"]);
+    }
+}
+
+#[cfg(not(feature = "nightly-testing"))]
+mod inner {
+    pub fn main() {}
+}
+
+fn main() {
+    inner::main()
+}

serde_macros/tests/skeptic.rs

@@ -0,0 +1,3 @@
+#![cfg(feature = "nightly-testing")]
+
+include!(concat!(env!("OUT_DIR"), "/skeptic-tests.rs"));

serde_macros/tests/test.rs

@@ -6,3 +6,4 @@ extern crate test;
 include!("../../testing/tests/test.rs.in");
 
 mod compile_tests;
+mod skeptic;