70 lines
2.2 KiB
Go
70 lines
2.2 KiB
Go
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package astro
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import (
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"math"
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"testing"
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"time"
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"b612.me/astro/basic"
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)
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// time.Time 往返经 JD 舍入，容差为 0.2 ms。
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func TestBarycentricTimeFacade(t *testing.T) {
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tt := time.Date(2026, 1, 1, 0, 0, 0, 0, time.UTC)
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if got := TCGMinusTT(tt); math.Abs(got-1.0777) > 5e-3 {
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t.Errorf("TCG−TT=%v 秒, want ≈1.078", got)
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}
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if got := TCBMinusTT(tt); math.Abs(got-23.9757) > 5e-3 {
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t.Errorf("TCB−TT=%v 秒, want ≈23.976", got)
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}
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if got := TDBMinusTT(tt); math.Abs(got) > 2e-3 {
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t.Errorf("TDB−TT=%v 秒, want |·| ≤ 1.7 ms", got)
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}
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for _, tc := range []struct {
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name string
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fwd func(time.Time) time.Time
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back func(time.Time) time.Time
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}{
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{"TCG", TCGFromTT, TTFromTCG},
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{"TCB", TCBFromTT, TTFromTCB},
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{"TDB", TDBFromTT, TTFromTDB},
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} {
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round := tc.back(tc.fwd(tt))
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if delta := math.Abs(round.Sub(tt).Seconds()); delta > 2e-4 {
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t.Errorf("%s 往返差 %.6f 秒", tc.name, delta)
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}
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if forward := tc.fwd(tt); !forward.After(tt.Add(-time.Second)) || !forward.Before(tt.Add(time.Minute)) {
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t.Errorf("%s 结果 %v 离开合理区间", tc.name, forward)
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}
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}
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tcb := TCBFromTT(tt)
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if diff := tcb.Sub(TDBFromTCB(tcb)).Seconds(); math.Abs(diff-23.9757) > 0.1 {
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t.Errorf("TCB−TDB=%v 秒, want ≈23.976", diff)
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}
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if delta := math.Abs(TTFromTCB(tcb).Sub(tt).Seconds()); delta > 2e-4 {
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t.Errorf("TT→TCB 往返差 %.6f 秒", delta)
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}
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}
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func TestBarycentricTimeFacadePreservesScaleAndInstant(t *testing.T) {
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tt := time.Date(2026, 1, 1, 0, 0, 0, 0, time.UTC)
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for _, date := range []time.Time{tt, tt.In(time.FixedZone("UTC+08", 8*3600))} {
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jd := basic.Date2JD(date.UTC())
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for name, pair := range map[string][2]float64{
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"TCG": {TCGMinusTT(date), basic.TCGMinusTTSeconds(jd)},
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"TCB": {TCBMinusTT(date), basic.TCBMinusTTSeconds(jd)},
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"TDB": {TDBMinusTT(date), basic.TDBMinusTTSeconds(jd)},
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} {
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if pair[0] != pair[1] {
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t.Errorf("%s facade=%v, basic=%v", name, pair[0], pair[1])
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}
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}
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if direct, composed := TDBFromTT(date), TDBFromTCB(TCBFromTT(date)); math.Abs(direct.Sub(composed).Seconds()) > 1e-4 {
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t.Errorf("direct TDB=%v, composed=%v", direct, composed)
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}
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if got := TCGFromTT(date); got.Location() != time.UTC || !got.Equal(TCGFromTT(tt)) {
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t.Errorf("TCG depends on input Location: %v", got)
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}
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}
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}
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