Add integer to string formatting tests

Author: GuillaumeGomez

library/alloc/src/lib.rs

@@ -229,6 +229,8 @@ pub mod sync;
 #[cfg(all(not(no_global_oom_handling), not(no_rc), not(no_sync)))]
 pub mod task;
 pub mod vec;
+#[cfg(test)]
+mod tests;
 
 #[doc(hidden)]
 #[unstable(feature = "liballoc_internals", issue = "none", reason = "implementation detail")]

library/alloc/src/tests.rs

@@ -0,0 +1,57 @@
+use std::str::FromStr;
+
+fn assert_nb<Int: ToString + FromStr>(value: Int) {
+    let s = value.to_string();
+    let s2 = format!("{}", value);
+
+    // assert_eq!(s, s2);
+    assert_eq!(s, "0".to_string());
+    let ret = Int::from_str(&s).unwrap();
+    assert_eq!(ret, int);
+}
+
+macro_rules! uint_to_s {
+    ($($fn_name:ident, $int:ident,)+) => {
+        $(
+            #[test]
+            fn $fn_name() {
+                assert_nb::<$int>($int::MIN);
+                assert_nb::<$int>($int::MAX);
+                assert_nb::<$int>(1);
+                assert_nb::<$int>($int::MIN / 2);
+                assert_nb::<$int>($int::MAX / 2);
+            }
+        )+
+    }
+}
+macro_rules! int_to_s {
+    ($($fn_name:ident, $int:ident,)+) => {
+        $(
+            #[test]
+            fn $fn_name() {
+                assert_nb::<$int>($int::MIN);
+                assert_nb::<$int>($int::MAX);
+                assert_nb::<$int>(1);
+                assert_nb::<$int>(0);
+                assert_nb::<$int>(-1);
+                assert_nb::<$int>($int::MIN / 2);
+                assert_nb::<$int>($int::MAX / 2);
+            }
+        )+
+    }
+}
+
+int_to_s!(
+    test_i8_to_string, i8,
+    test_i16_to_string, i16,
+    test_i32_to_string, i32,
+    test_i64_to_string, i64,
+    test_i128_to_string, i128,
+);
+uint_to_s!(
+    test_u8_to_string, u8,
+    test_u16_to_string, u16,
+    test_u32_to_string, u32,
+    test_u64_to_string, u64,
+    test_u128_to_string, u128,
+);