Re: [PATCH v1] rust: time: Add examples with doctest for Delta

[FUJITA Tomonori]

On Wed, 02 Jul 2025 10:36:19 +0200
Andreas Hindborg <a.hindborg@xxxxxxxxxx> wrote:

> "FUJITA Tomonori" <fujita.tomonori@xxxxxxxxx> writes:
> 
>> Add examples with doctest for Delta methods and associated
>> functions. These examples explicitly test overflow and saturation
>> behavior.
>>
>> Signed-off-by: FUJITA Tomonori <fujita.tomonori@xxxxxxxxx>
>> ---
>>  rust/kernel/time.rs | 67 +++++++++++++++++++++++++++++++++++++++++++++
>>  1 file changed, 67 insertions(+)
>>
>> diff --git a/rust/kernel/time.rs b/rust/kernel/time.rs
>> index 64c8dcf548d6..c6322275115a 100644
>> --- a/rust/kernel/time.rs
>> +++ b/rust/kernel/time.rs
>> @@ -228,11 +228,34 @@ impl Delta {
>>      /// A span of time equal to zero.
>>      pub const ZERO: Self = Self { nanos: 0 };
>>
>> +    /// Create a new [`Delta`] from a number of nanoseconds.
>> +    ///
>> +    /// The `nanos` can range from [`i64::MIN`] to [`i64::MAX`].
>> +    #[inline]
>> +    pub const fn from_nanos(nanos: i64) -> Self {
>> +        Self { nanos }
>> +    }
>> +
>>      /// Create a new [`Delta`] from a number of microseconds.
>>      ///
>>      /// The `micros` can range from -9_223_372_036_854_775 to 9_223_372_036_854_775.
>>      /// If `micros` is outside this range, `i64::MIN` is used for negative values,
>>      /// and `i64::MAX` is used for positive values due to saturation.
>> +    ///
>> +    /// # Examples
>> +    ///
>> +    /// ```
>> +    /// let delta = kernel::time::Delta::from_micros(5);
>> +    /// assert_eq!(delta.as_nanos(), 5_000);
>> +    /// let delta = kernel::time::Delta::from_micros(9_223_372_036_854_775);
>> +    /// assert_eq!(delta.as_nanos(), 9_223_372_036_854_775_000);
>> +    /// let delta = kernel::time::Delta::from_micros(9_223_372_036_854_776);
>> +    /// assert_eq!(delta.as_nanos(), i64::MAX);
>> +    /// let delta = kernel::time::Delta::from_micros(-9_223_372_036_854_775);
>> +    /// assert_eq!(delta.as_nanos(), -9_223_372_036_854_775_000);
>> +    /// let delta = kernel::time::Delta::from_micros(-9_223_372_036_854_776);
>> +    /// assert_eq!(delta.as_nanos(), i64::MIN);
>> +    /// ```
> 
> 
> I think this kind of test would be better suited for the new `#[test]`
> macro. Would you agree?

I think that Miguel suggested adding examples but either is fine by me:

https://lore.kernel.org/lkml/CANiq72kiTwpcH6S0XaTEBnLxqyJ6EDVLoZPi9X+MWkanK5wq=w@xxxxxxxxxxxxxx/