go.chromium.org/luci@v0.0.0-20240309015107-7cdc2e660f33/cv/internal/common/project_distribuition_test.go (about)

     1  // Copyright 2020 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 common
    16  
    17  import (
    18  	"fmt"
    19  	"sort"
    20  	"testing"
    21  	"time"
    22  
    23  	. "github.com/smartystreets/goconvey/convey"
    24  )
    25  
    26  func TestProjectOffset(t *testing.T) {
    27  	t.Parallel()
    28  
    29  	Convey("DistributeOffset forms uniformish distribution", t, func() {
    30  
    31  		testIntervalOf100x := func(d time.Duration) {
    32  			Convey((100 * d).String(), func() {
    33  				offsets := make([]time.Duration, 101)
    34  				for i := 0; i < 101; i++ {
    35  					project := fmt.Sprintf("project-%d", i*i)
    36  					offsets[i] = DistributeOffset(100*d, "kind", project)
    37  				}
    38  				sort.Slice(offsets, func(i, j int) bool { return offsets[i] < offsets[j] })
    39  				So(offsets[0], ShouldBeGreaterThanOrEqualTo, time.Duration(0))
    40  				for i, o := range offsets {
    41  					min := time.Duration(i-10) * d
    42  					max := time.Duration(i+10) * d
    43  					So(o, ShouldBeBetweenOrEqual, min, max)
    44  				}
    45  				So(offsets[100], ShouldBeLessThan, 100*d)
    46  			})
    47  		}
    48  
    49  		testIntervalOf100x(time.Nanosecond)
    50  		testIntervalOf100x(time.Millisecond)
    51  		testIntervalOf100x(10 * time.Millisecond)
    52  		testIntervalOf100x(100 * time.Millisecond)
    53  		testIntervalOf100x(time.Second)
    54  		testIntervalOf100x(time.Minute)
    55  		testIntervalOf100x(time.Hour)
    56  		testIntervalOf100x(7 * 24 * time.Hour)
    57  	})
    58  }