ControllableClock

prism3_clock

Trait ControllableClock 

Source 
pub trait ControllableClock: Clock {
    // Required methods
    fn set_time(&self, instant: DateTime<Utc>);
    fn add_duration(&self, duration: Duration);
    fn reset(&self);
}
Expand description

A trait representing a clock that can be controlled.

This trait extends Clock to provide methods for manually setting and advancing the clock’s time. It’s primarily designed for testing scenarios where you need precise control over time.

§Warning

This trait should only be used in testing code, not in production code.

§Examples

use prism3_clock::{Clock, ControllableClock, MockClock};
use chrono::{DateTime, Duration, Utc};

let clock = MockClock::new();

// Set to a specific time
let fixed_time = DateTime::parse_from_rfc3339(
    "2024-01-01T00:00:00Z"
).unwrap().with_timezone(&Utc);
clock.set_time(fixed_time);

assert_eq!(clock.time(), fixed_time);

// Advance by 1 hour
clock.add_duration(Duration::hours(1));
assert_eq!(
    clock.time(),
    fixed_time + Duration::hours(1)
);

§Author

Haixing Hu

Required Methods§

Source

fn set_time(&self, instant: DateTime<Utc>)

Sets the clock to a specific time.

§Arguments
  • instant - The time to set the clock to (UTC).
§Examples
use prism3_clock::{Clock, ControllableClock, MockClock};
use chrono::{DateTime, Utc};

let clock = MockClock::new();
let time = DateTime::parse_from_rfc3339(
    "2024-01-01T00:00:00Z"
).unwrap().with_timezone(&Utc);

clock.set_time(time);
assert_eq!(clock.time(), time);
Source

fn add_duration(&self, duration: Duration)

Advances the clock by the specified duration.

§Arguments
  • duration - The duration to advance the clock by.
§Examples
use prism3_clock::{Clock, ControllableClock, MockClock};
use chrono::Duration;

let clock = MockClock::new();
let before = clock.time();

clock.add_duration(Duration::hours(1));

let after = clock.time();
assert_eq!(after - before, Duration::hours(1));
Source

fn reset(&self)

Resets the clock to its initial state.

The exact behavior of this method depends on the implementation. For MockClock, it resets to the time when the clock was created.

§Examples
use prism3_clock::{Clock, ControllableClock, MockClock};
use chrono::Duration;

let clock = MockClock::new();
let initial = clock.time();

clock.add_duration(Duration::hours(1));
clock.reset();

// After reset, time should be close to initial time
let diff = (clock.time() - initial).num_milliseconds().abs();
assert!(diff < 100); // Allow small difference

Implementors§