Fix tests related to no_std

Author: sanxiyn

src/librand/distributions/exponential.rs

@@ -10,6 +10,7 @@
 
 //! The exponential distribution.
 
+#[cfg(not(test))] // only necessary for no_std
 use FloatMath;
 
 use {Rng, Rand};

src/librand/distributions/gamma.rs

@@ -13,6 +13,7 @@
 use self::GammaRepr::*;
 use self::ChiSquaredRepr::*;
 
+#[cfg(not(test))] // only necessary for no_std
 use FloatMath;
 
 use {Rng, Open01};

src/librand/distributions/mod.rs

@@ -17,7 +17,9 @@
 //! internally. The `IndependentSample` trait is for generating values
 //! that do not need to record state.
 
+#[cfg(not(test))] // only necessary for no_std
 use core::num::Float;
+
 use core::marker::PhantomData;
 
 use {Rng, Rand};

src/librand/distributions/normal.rs

@@ -10,6 +10,7 @@
 
 //! The normal and derived distributions.
 
+#[cfg(not(test))] // only necessary for no_std
 use FloatMath;
 
 use {Rng, Rand, Open01};

src/librand/lib.rs

@@ -28,13 +28,13 @@
 #![unstable(feature = "rand",
             reason = "use `rand` from crates.io",
             issue = "27703")]
-#![feature(core_float)]
 #![feature(core_intrinsics)]
 #![feature(staged_api)]
 #![feature(step_by)]
 #![feature(custom_attribute)]
 #![allow(unused_attributes)]
 
+#![cfg_attr(not(test), feature(core_float))] // only necessary for no_std
 #![cfg_attr(test, feature(test, rand))]
 
 #![allow(deprecated)]