segments/segments_test.go

   1 package segments
   2
   3 import (
   4         "testing"
   5
   6         "github.com/stretchr/testify/assert"
   7 )
   8
   9 func LengthIterFromSlice(ls []Length) LengthIter {
  10         return func() (Length, bool) {
  11                 switch len(ls) {
  12                 case 0:
  13                         return -1, false
  14                 default:
  15                         l := ls[0]
  16                         ls = ls[1:]
  17                         return l, true
  18                 }
  19         }
  20 }
  21
  22 type ScanCallbackValue struct {
  23         Index int
  24         Extent
  25 }
  26
  27 type collectExtents []ScanCallbackValue
  28
  29 func (me *collectExtents) scanCallback(i int, e Extent) bool {
  30         *me = append(*me, ScanCallbackValue{
  31                 Index:  i,
  32                 Extent: e,
  33         })
  34         return true
  35 }
  36
  37 type newLocater func(LengthIter) Locater
  38
  39 func assertLocate(t *testing.T, nl newLocater, ls []Length, needle Extent, firstExpectedIndex int, expectedExtents []Extent) {
  40         var actual collectExtents
  41         var expected collectExtents
  42         for i, e := range expectedExtents {
  43                 expected.scanCallback(firstExpectedIndex+i, e)
  44         }
  45         nl(LengthIterFromSlice(ls))(needle, actual.scanCallback)
  46         assert.EqualValues(t, expected, actual)
  47 }
  48
  49 func testLocater(t *testing.T, newLocater newLocater) {
  50         assertLocate(t, newLocater,
  51                 []Length{1, 0, 2, 0, 3},
  52                 Extent{2, 2},
  53                 2,
  54                 []Extent{{1, 1}, {0, 0}, {0, 1}})
  55         assertLocate(t, newLocater,
  56                 []Length{1, 0, 2, 0, 3},
  57                 Extent{6, 2},
  58                 2,
  59                 []Extent{})
  60         assertLocate(t, newLocater,
  61                 []Length{1652, 1514, 1554, 1618, 1546, 129241752, 1537}, // 128737588
  62                 Extent{0, 16384},
  63                 0,
  64                 []Extent{
  65                         {0, 1652},
  66                         {0, 1514},
  67                         {0, 1554},
  68                         {0, 1618},
  69                         {0, 1546},
  70                         {0, 8500},
  71                 })
  72         assertLocate(t, newLocater,
  73                 []Length{1652, 1514, 1554, 1618, 1546, 129241752, 1537, 1536, 1551}, // 128737588
  74                 Extent{129236992, 16384},
  75                 5,
  76                 []Extent{
  77                         {129229108, 12644},
  78                         {0, 1537},
  79                         {0, 1536},
  80                         {0, 667},
  81                 })
  82 }
  83
  84 func TestScan(t *testing.T) {
  85         testLocater(t, LocaterFromLengthIter)
  86 }
  87
  88 func TestIndex(t *testing.T) {
  89         testLocater(t, func(li LengthIter) Locater {
  90                 return NewIndex(li).Locate
  91         })
  92 }