Fix compiler warnings when testing

src/tests/mod.rs

@@ -1,4 +1,6 @@
+//! Library tests and fixtures
+
 pub mod model;
 mod schema;
-pub mod query_tests;
+#[cfg(test)] mod query_tests;
-pub mod introspection_tests;
+#[cfg(test)] mod introspection_tests;

src/tests/model.rs

@@ -1,3 +1,5 @@
+#![allow(missing_docs)]
+
 use std::collections::HashMap;
 
 #[derive(Copy, Clone, Eq, PartialEq, Debug)]