collatz_test.gno

 1package collatz
 2
 3import (
 4	"strings"
 5	"testing"
 6
 7	"gno.land/p/nt/testutils/v0"
 8	"gno.land/p/nt/uassert/v0"
 9)
10
11func TestStopping(t *testing.T) {
12	cases := []struct {
13		n     int64
14		steps int
15		peak  int64
16	}{
17		{1, 0, 1},
18		{2, 1, 2},
19		{6, 8, 16},
20		{7, 16, 52},
21		{27, 111, 9232},
22	}
23	for _, c := range cases {
24		steps, peak, _ := stopping(c.n)
25		uassert.Equal(t, c.steps, steps)
26		uassert.Equal(t, c.peak, peak)
27	}
28}
29
30func TestComputeAndLeaderboard(cur realm, t *testing.T) {
31	addr := testutils.TestAddress("alice")
32	testing.SetRealm(testing.NewUserRealm(addr))
33
34	Compute(cross(cur), 27)
35	Compute(cross(cur), 6)
36
37	out := Render("")
38	uassert.True(t, strings.Contains(out, "Leaderboard"), "has leaderboard")
39	uassert.True(t, strings.Contains(out, "9232"), "shows peak of 27")
40	// 27 has more steps than 6, so it must appear first (rank 1).
41	i27 := strings.Index(out, "[27]")
42	i6 := strings.Index(out, "[6]")
43	uassert.True(t, i27 >= 0 && i6 >= 0, "both rows present")
44	uassert.True(t, i27 < i6, "27 ranked above 6")
45}
46
47func TestComputeRejectsNonPositive(cur realm, t *testing.T) {
48	addr := testutils.TestAddress("bob")
49	testing.SetRealm(testing.NewUserRealm(addr))
50	uassert.AbortsWithMessage(t, cur, "n must be > 0", func() {
51		Compute(cross(cur), 0)
52	})
53}
54
55func TestRenderSequence(t *testing.T) {
56	out := Render("/6")
57	uassert.True(t, strings.Contains(out, "6 → 3 → 10 → 5 → 16 → 8 → 4 → 2 → 1"), "full seq for 6")
58	uassert.True(t, strings.Contains(out, "steps: 8"), "reports 8 steps")
59
60	bad := Render("/abc")
61	uassert.True(t, strings.Contains(bad, "Invalid"), "rejects non-numeric path")
62}
63
64// 3n+1 for this n is exactly 2^64, which wraps to 0. Recording it would put a
65// million-step walk on 0 at the top of the leaderboard, forever.
66func TestComputeRefusesAnOverflowingWalk(cur realm, t *testing.T) {
67	uassert.AbortsContains(t, cur, "overflows int64", func() { Compute(cross(cur), 6148914691236517205) })
68	_, _, ok := stopping(27)
69	uassert.True(t, ok, "an ordinary walk is unaffected")
70	out := Render("/6148914691236517205")
71	uassert.True(t, strings.Contains(out, "would overflow int64"), out)
72	uassert.False(t, strings.Contains(out, "→ 0"), "no wrapped term rendered")
73}