diff --git a/src/liballoc/tests/string.rs b/src/liballoc/tests/string.rs
index d1e746ea43b45..9bbba4e22b03d 100644
--- a/src/liballoc/tests/string.rs
+++ b/src/liballoc/tests/string.rs
@@ -9,8 +9,11 @@
 // except according to those terms.
 
 use std::borrow::Cow;
+#[cfg(not(target_arch = "asmjs"))]
 use std::collections::CollectionAllocErr::*;
+#[cfg(not(target_arch = "asmjs"))]
 use std::mem::size_of;
+#[cfg(not(target_arch = "asmjs"))]
 use std::{usize, isize};
 
 pub trait IntoCow<'a, B: ?Sized> where B: ToOwned {
@@ -532,6 +535,7 @@ fn test_reserve_exact() {
     assert!(s.capacity() >= 33)
 }
 
+#[cfg(not(target_arch = "asmjs"))]
 #[test]
 fn test_try_reserve() {
 
@@ -609,6 +613,7 @@ fn test_try_reserve() {
 
 }
 
+#[cfg(not(target_arch = "asmjs"))]
 #[test]
 fn test_try_reserve_exact() {
 
diff --git a/src/liballoc/tests/vec.rs b/src/liballoc/tests/vec.rs
index 3c17a401bbaf5..85e11d8b8ee6e 100644
--- a/src/liballoc/tests/vec.rs
+++ b/src/liballoc/tests/vec.rs
@@ -10,8 +10,11 @@
 
 use std::borrow::Cow;
 use std::mem::size_of;
-use std::{usize, isize, panic};
+use std::{usize, panic};
+#[cfg(not(target_arch = "asmjs"))]
+use std::isize;
 use std::vec::{Drain, IntoIter};
+#[cfg(not(target_arch = "asmjs"))]
 use std::collections::CollectionAllocErr::*;
 
 struct DropCounter<'a> {
@@ -991,6 +994,7 @@ fn test_reserve_exact() {
     assert!(v.capacity() >= 33)
 }
 
+#[cfg(not(target_arch = "asmjs"))]
 #[test]
 fn test_try_reserve() {
 
@@ -1093,6 +1097,7 @@ fn test_try_reserve() {
 
 }
 
+#[cfg(not(target_arch = "asmjs"))]
 #[test]
 fn test_try_reserve_exact() {
 
diff --git a/src/liballoc/tests/vec_deque.rs b/src/liballoc/tests/vec_deque.rs
index fc1a0b624a555..9fd38ed6f6f49 100644
--- a/src/liballoc/tests/vec_deque.rs
+++ b/src/liballoc/tests/vec_deque.rs
@@ -11,9 +11,13 @@
 use std::collections::VecDeque;
 use std::fmt::Debug;
 use std::collections::vec_deque::{Drain};
+#[cfg(not(target_arch = "asmjs"))]
 use std::collections::CollectionAllocErr::*;
+#[cfg(not(target_arch = "asmjs"))]
 use std::mem::size_of;
-use std::{usize, isize};
+use std::isize;
+#[cfg(not(target_arch = "asmjs"))]
+use std::usize;
 
 use self::Taggy::*;
 use self::Taggypar::*;
@@ -1049,6 +1053,7 @@ fn test_reserve_exact_2() {
     assert!(v.capacity() >= 48)
 }
 
+#[cfg(not(target_arch = "asmjs"))]
 #[test]
 fn test_try_reserve() {
 
@@ -1150,6 +1155,7 @@ fn test_try_reserve() {
 
 }
 
+#[cfg(not(target_arch = "asmjs"))]
 #[test]
 fn test_try_reserve_exact() {
 
diff --git a/src/libstd/collections/hash/map.rs b/src/libstd/collections/hash/map.rs
index b18b38ec30246..5f5dec2dd4ff1 100644
--- a/src/libstd/collections/hash/map.rs
+++ b/src/libstd/collections/hash/map.rs
@@ -2755,8 +2755,11 @@ mod test_map {
     use cell::RefCell;
     use rand::{thread_rng, Rng};
     use panic;
+    #[cfg(not(target_arch = "asmjs"))]
     use realstd::collections::CollectionAllocErr::*;
+    #[cfg(not(target_arch = "asmjs"))]
     use realstd::mem::size_of;
+    #[cfg(not(target_arch = "asmjs"))]
     use realstd::usize;
 
     #[test]
@@ -3693,6 +3696,7 @@ mod test_map {
         assert_eq!(hm.len(), 0);
     }
 
+    #[cfg(not(target_arch = "asmjs"))]
     #[test]
     fn test_try_reserve() {