MAINT: Test with no-default-features (so no_std) in travis too

.travis.yml

@@ -16,6 +16,8 @@ branches:
 # the main build
 script:
   - |
+      cargo build -v --no-default-features &&
+      cargo test -v --no-default-features &&
       cargo build -v --features=$FEATURES &&
       cargo test -v --features=$FEATURES &&
       if [[ "$TRAVIS_RUST_VERSION" == "nightly" ]]; then

src/algorithms.rs

@@ -468,6 +468,7 @@ pub fn merge_internal_ranges<T: Ord>(data: &mut [T], left_end: usize, buffer: &m
     Ok(())
 }
 
+#[cfg(feature="use_std")]
 #[test]
 fn test_merge_internal() {
     let mut buffer = [0; 128];

src/container.rs

@@ -660,7 +660,7 @@ fn intervals() {
         for elt in &mut arr[r] {
             *elt += 1;
         }
-        println!("{:?}", &mut arr[r]);
+        // println!("{:?}", &mut arr[r]);
     });
 }
 

tests/vec.rs

@@ -1,3 +1,4 @@
+#![cfg(feature="use_std")]
 
 extern crate indexing;