1 // Copyright (c) 2013-2017 The btcsuite developers
2 // Use of this source code is governed by an ISC
3 // license that can be found in the LICENSE file.
13 // TestMedianTime tests the medianTime implementation.
14 func TestMedianTime(t *testing.T) {
20 // Not enough samples must result in an offset of 0.
21 {in: []int64{1}, wantOffset: 0},
22 {in: []int64{1, 2}, wantOffset: 0},
23 {in: []int64{1, 2, 3}, wantOffset: 0},
24 {in: []int64{1, 2, 3, 4}, wantOffset: 0},
26 // Various number of entries. The expected offset is only
27 // updated on odd number of elements.
28 {in: []int64{-13, 57, -4, -23, -12}, wantOffset: -12},
29 {in: []int64{55, -13, 61, -52, 39, 55}, wantOffset: 39},
30 {in: []int64{-62, -58, -30, -62, 51, -30, 15}, wantOffset: -30},
31 {in: []int64{29, -47, 39, 54, 42, 41, 8, -33}, wantOffset: 39},
32 {in: []int64{37, 54, 9, -21, -56, -36, 5, -11, -39}, wantOffset: -11},
33 {in: []int64{57, -28, 25, -39, 9, 63, -16, 19, -60, 25}, wantOffset: 9},
34 {in: []int64{-5, -4, -3, -2, -1}, wantOffset: -3, useDupID: true},
36 // The offset stops being updated once the max number of entries
37 // has been reached. This is actually a bug from Bitcoin Core,
38 // but since the time is ultimately used as a part of the
39 // consensus rules, it must be mirrored.
40 {in: []int64{-67, 67, -50, 24, 63, 17, 58, -14, 5, -32, -52}, wantOffset: 17},
41 {in: []int64{-67, 67, -50, 24, 63, 17, 58, -14, 5, -32, -52, 45}, wantOffset: 17},
42 {in: []int64{-67, 67, -50, 24, 63, 17, 58, -14, 5, -32, -52, 45, 4}, wantOffset: 17},
44 // Offsets that are too far away from the local time should
46 {in: []int64{-4201, 4202, -4203, 4204, -4205}, wantOffset: 0},
48 // Excerise the condition where the median offset is greater
49 // than the max allowed adjustment, but there is at least one
50 // sample that is close enough to the current time to avoid
51 // triggering a warning about an invalid local clock.
52 {in: []int64{4201, 4202, 4203, 4204, -299}, wantOffset: 0},
55 // Modify the max number of allowed median time entries for these tests.
56 maxMedianTimeEntries = 10
57 defer func() { maxMedianTimeEntries = 200 }()
59 for i, test := range tests {
60 filter := NewMedianTime()
61 for j, offset := range test.in {
63 now := time.Unix(time.Now().Unix(), 0)
64 tOffset := now.Add(time.Duration(offset) * time.Second)
65 filter.AddTimeSample(id, tOffset)
67 // Ensure the duplicate IDs are ignored.
69 // Modify the offsets to ensure the final median
70 // would be different if the duplicate is added.
71 tOffset = tOffset.Add(time.Duration(offset) *
73 filter.AddTimeSample(id, tOffset)
77 // Since it is possible that the time.Now call in AddTimeSample
78 // and the time.Now calls here in the tests will be off by one
79 // second, allow a fudge factor to compensate.
80 gotOffset := filter.Offset()
81 wantOffset := time.Duration(test.wantOffset) * time.Second
82 wantOffset2 := time.Duration(test.wantOffset-1) * time.Second
83 if gotOffset != wantOffset && gotOffset != wantOffset2 {
84 t.Errorf("Offset #%d: unexpected offset -- got %v, "+
85 "want %v or %v", i, gotOffset, wantOffset,
90 // Since it is possible that the time.Now call in AdjustedTime
91 // and the time.Now call here in the tests will be off by one
92 // second, allow a fudge factor to compensate.
93 adjustedTime := filter.AdjustedTime()
94 now := time.Unix(time.Now().Unix(), 0)
95 wantTime := now.Add(filter.Offset())
96 wantTime2 := now.Add(filter.Offset() - time.Second)
97 if !adjustedTime.Equal(wantTime) && !adjustedTime.Equal(wantTime2) {
98 t.Errorf("AdjustedTime #%d: unexpected result -- got %v, "+
99 "want %v or %v", i, adjustedTime, wantTime,