diff --git a/src/lib.rs b/src/lib.rs
index 9acd058..a310574 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -5,8 +5,13 @@
 #[allow(unstable)]
 extern crate core;
 
+#[cfg(test)]
+#[macro_use]
+extern crate std;
+
 pub use context::Context;
 
+#[cfg(not(test))]
 mod std { pub use core::*; }
 
 mod context;