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https://github.com/rzajac/clock
Package clock is a thin wrapper around time.Now() to help testing time dependent code.
https://github.com/rzajac/clock
Last synced: 3 days ago
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Package clock is a thin wrapper around time.Now() to help testing time dependent code.
- Host: GitHub
- URL: https://github.com/rzajac/clock
- Owner: rzajac
- License: apache-2.0
- Created: 2021-01-08T15:15:27.000Z (almost 4 years ago)
- Default Branch: master
- Last Pushed: 2021-01-10T21:40:57.000Z (almost 4 years ago)
- Last Synced: 2023-07-27T22:35:44.948Z (over 1 year ago)
- Language: Go
- Size: 13.7 KB
- Stars: 2
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
[](https://goreportcard.com/report/github.com/rzajac/clock)
[](https://pkg.go.dev/github.com/rzajac/clock)
# clock
Testing code which uses `time.Now()` is hard and in many instances impossible.
Package `clock` is an attempt to simplify this kind of tests by providing
package level clock and few test clock implementations.
# Installation
```
go get github.com/rzajac/clock
```
# Usage
## Inject clock implementation.
Production code:
```
func NewStruct(clk clock.Clock) {
// ...
now := clk()
// ...
}
s := NewStruct(time.Now)
// or
s := NewStruct(clock.Now) // Works exaclty the same way as time.Now().
```
Tests:
```
tim := time.Date(2020, 1, 1, 0, 0, 0, 0, time.UTC)
s := NewStruct(clock.Fixed(start))
```
## Set clock globally
In case your code already uses `time.Now()` and you are not able to use
injection method, use package level clock and override its implementation in
tests.
Production code:
```
func doStuff() {
// ...
doOtherStuff(clock.Now())
// ...
}
```
Tests:
```
tim := time.Date(2020, 1, 1, 0, 0, 0, 0, time.UTC)
clock.SetClock(clock.Fixed(tim))
defer clock.SetDefault() // Make sure you set package level clock to default!
// Perform your tests.
```
## Useful clock implementations.
Package `clock` provides few useful "clock" you can use in your tests.
- `StartingAt(tim time.Time)` - sets current time.
- `Fixed(tim time.Time)` - clock always returning the same time.
```
tim := time.Date(2020, 1, 1, 0, 0, 0, 0, time.UTC)
clk := clock.Fixed(tim)
fmt.Println(clk().Format(time.RFC3339)) // 2020-01-01T00:00:00Z
fmt.Println(clk().Format(time.RFC3339)) // 2020-01-01T00:00:00Z
fmt.Println(clk().Format(time.RFC3339)) // 2020-01-01T00:00:00Z
```
- `Deterministic(start time.Time, tick time.Duration)` - clock which advances
given start time by tick every time you call it (no matter now fast or slow
you do it).
```
start := time.Date(2020, 1, 1, 0, 0, 0, 0, time.UTC)
clk := clock.Deterministic(start, time.Second)
fmt.Println(clk().Format(time.RFC3339)) // 2020-01-01T00:00:00Z
fmt.Println(clk().Format(time.RFC3339)) // 2020-01-01T00:00:01Z
fmt.Println(clk().Format(time.RFC3339)) // 2020-01-01T00:00:02Z
```
## Benchmarks
```
BenchmarkClockNow-12 27322105 42.9 ns/op 0 B/op 0 allocs/op
BenchmarkTimeNow-12 28653739 42.0 ns/op 0 B/op 0 allocs/op
```
## License
Apache License, Version 2.0