PrimInt: add unit tests for reverse_bits

src/int.rs

@@ -466,3 +466,59 @@ prim_int_impl!(i64, i64, u64);
 #[cfg(has_i128)]
 prim_int_impl!(i128, i128, u128);
 prim_int_impl!(isize, isize, usize);
+
+#[cfg(test)]
+mod tests {
+    use int::PrimInt;
+
+    #[test]
+    pub fn reverse_bits() {
+        use core::{i16, i32, i64, i8};
+
+        assert_eq!(
+            PrimInt::reverse_bits(0x0123_4567_89ab_cdefu64),
+            0xf7b3_d591_e6a2_c480
+        );
+
+        assert_eq!(PrimInt::reverse_bits(0i8), 0);
+        assert_eq!(PrimInt::reverse_bits(-1i8), -1);
+        assert_eq!(PrimInt::reverse_bits(1i8), i8::MIN);
+        assert_eq!(PrimInt::reverse_bits(i8::MIN), 1);
+        assert_eq!(PrimInt::reverse_bits(-2i8), i8::MAX);
+        assert_eq!(PrimInt::reverse_bits(i8::MAX), -2);
+
+        assert_eq!(PrimInt::reverse_bits(0i16), 0);
+        assert_eq!(PrimInt::reverse_bits(-1i16), -1);
+        assert_eq!(PrimInt::reverse_bits(1i16), i16::MIN);
+        assert_eq!(PrimInt::reverse_bits(i16::MIN), 1);
+        assert_eq!(PrimInt::reverse_bits(-2i16), i16::MAX);
+        assert_eq!(PrimInt::reverse_bits(i16::MAX), -2);
+
+        assert_eq!(PrimInt::reverse_bits(0i32), 0);
+        assert_eq!(PrimInt::reverse_bits(-1i32), -1);
+        assert_eq!(PrimInt::reverse_bits(1i32), i32::MIN);
+        assert_eq!(PrimInt::reverse_bits(i32::MIN), 1);
+        assert_eq!(PrimInt::reverse_bits(-2i32), i32::MAX);
+        assert_eq!(PrimInt::reverse_bits(i32::MAX), -2);
+
+        assert_eq!(PrimInt::reverse_bits(0i64), 0);
+        assert_eq!(PrimInt::reverse_bits(-1i64), -1);
+        assert_eq!(PrimInt::reverse_bits(1i64), i64::MIN);
+        assert_eq!(PrimInt::reverse_bits(i64::MIN), 1);
+        assert_eq!(PrimInt::reverse_bits(-2i64), i64::MAX);
+        assert_eq!(PrimInt::reverse_bits(i64::MAX), -2);
+    }
+
+    #[test]
+    #[cfg(has_i128)]
+    pub fn reverse_bits_i128() {
+        use core::i128;
+
+        assert_eq!(PrimInt::reverse_bits(0i128), 0);
+        assert_eq!(PrimInt::reverse_bits(-1i128), -1);
+        assert_eq!(PrimInt::reverse_bits(1i128), i128::MIN);
+        assert_eq!(PrimInt::reverse_bits(i128::MIN), 1);
+        assert_eq!(PrimInt::reverse_bits(-2i128), i128::MAX);
+        assert_eq!(PrimInt::reverse_bits(i128::MAX), -2);
+    }
+}