go.chromium.org/luci@v0.0.0-20240309015107-7cdc2e660f33/common/clock/systemtimer_test.go (about)

     1  // Copyright 2015 The LUCI Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //      http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package clock
    16  
    17  import (
    18  	"context"
    19  	"testing"
    20  	"time"
    21  
    22  	. "github.com/smartystreets/goconvey/convey"
    23  )
    24  
    25  func TestSystemTimer(t *testing.T) {
    26  	t.Parallel()
    27  
    28  	Convey(`A systemTimer instance`, t, func() {
    29  		ctx, cancelFunc := context.WithCancel(context.Background())
    30  		t := GetSystemClock().NewTimer(ctx)
    31  		defer t.Stop()
    32  
    33  		Convey(`Should start with a non-nil channel.`, func() {
    34  			So(t.GetC(), ShouldNotBeNil)
    35  		})
    36  
    37  		Convey(`When stopped, should return inactive.`, func() {
    38  			So(t.Stop(), ShouldBeFalse)
    39  		})
    40  
    41  		Convey(`Will return immediately if the Context is canceled before Reset.`, func() {
    42  			cancelFunc()
    43  
    44  			t.Reset(veryLongTime)
    45  			So((<-t.GetC()).Err, ShouldEqual, context.Canceled)
    46  		})
    47  
    48  		Convey(`Will return if the Context is canceled after Reset.`, func() {
    49  			t.Reset(veryLongTime)
    50  			cancelFunc()
    51  
    52  			So((<-t.GetC()).Err, ShouldEqual, context.Canceled)
    53  		})
    54  
    55  		Convey(`A timer will use the same channel when Reset.`, func() {
    56  			timerC := t.GetC()
    57  
    58  			// Reset our timer to something more reasonable. It should trigger the
    59  			// timer channel, which should trigger our
    60  			t.Reset(timeBase)
    61  			So((<-timerC).Err, ShouldBeNil)
    62  		})
    63  
    64  		Convey(`A timer will not signal if stopped.`, func() {
    65  			t.Reset(timeBase)
    66  			t.Stop()
    67  
    68  			// This isn't a perfect test, but it's a good boundary for flake.
    69  			time.Sleep(3 * timeBase)
    70  
    71  			triggered := false
    72  			select {
    73  			case <-t.GetC():
    74  				triggered = true
    75  			default:
    76  				break
    77  			}
    78  			So(triggered, ShouldBeFalse)
    79  		})
    80  
    81  		Convey(`When reset`, func() {
    82  			So(t.Reset(veryLongTime), ShouldBeFalse)
    83  
    84  			Convey(`When reset again to a short duration, should return that it was active and trigger.`, func() {
    85  				// Upper bound of supported platform resolution. Windows is 15ms, so
    86  				// make sure we exceed that.
    87  				So(t.Reset(timeBase), ShouldBeTrue)
    88  				So((<-t.GetC()).IsZero(), ShouldBeFalse)
    89  
    90  				// Again (reschedule).
    91  				So(t.Reset(timeBase), ShouldBeFalse)
    92  				So((<-t.GetC()).IsZero(), ShouldBeFalse)
    93  			})
    94  
    95  			Convey(`When stopped, should return active and have a non-nil C.`, func() {
    96  				active := t.Stop()
    97  				So(active, ShouldBeTrue)
    98  				So(t.GetC(), ShouldNotBeNil)
    99  			})
   100  
   101  			Convey(`When stopped, should return active.`, func() {
   102  				active := t.Stop()
   103  				So(active, ShouldBeTrue)
   104  			})
   105  
   106  			Convey(`Should have a non-nil channel.`, func() {
   107  				So(t.GetC(), ShouldNotBeNil)
   108  			})
   109  		})
   110  	})
   111  }