markov_test.gno

 1package markov
 2
 3import (
 4	"strings"
 5	"testing"
 6
 7	"gno.land/p/nt/uassert/v0"
 8)
 9
10func TestPrefixShiftKey(t *testing.T) {
11	p := make(Prefix, PrefixLen)
12	uassert.Equal(t, " ", p.key(), "initial key is two empty words joined")
13
14	p.shift("hello")
15	uassert.Equal(t, " hello", p.key(), "after one shift")
16
17	p.shift("world")
18	uassert.Equal(t, "hello world", p.key(), "after two shifts window is full")
19
20	p.shift("again")
21	uassert.Equal(t, "world again", p.key(), "oldest word drops off")
22}
23
24func TestBuildCountsAndSuffixes(t *testing.T) {
25	c := New()
26	added := c.Build("a b a b a b")
27	uassert.Equal(t, 6, added, "six words tokenized")
28
29	words, _ := c.Stats()
30	uassert.Equal(t, 6, words, "word counter matches")
31
32	// prefixes seen: " "->[a], " a"->[b], "a b"->[a,a], "b a"->[b,b]
33	uassert.True(t, c.table.Has("a b"), "prefix 'a b' recorded")
34	ab := c.table.Get("a b").(*suffixList)
35	uassert.Equal(t, 2, len(ab.words), "'a b' followed twice")
36	uassert.Equal(t, "a", ab.words[0], "'a b' is always followed by 'a'")
37
38	// whitespace-only / empty adds nothing
39	uassert.Equal(t, 0, c.Build("   "), "blank text adds no words")
40}
41
42func TestGenerateDeterministicAndBounded(t *testing.T) {
43	c := New()
44	c.Build("one two three four one two three five one two six")
45
46	a := strings.Join(c.Generate(8, 42), " ")
47	b := strings.Join(c.Generate(8, 42), " ")
48	uassert.Equal(t, a, b, "same seed => identical output")
49
50	// the walk is seed-sensitive: across a spread of seeds at least one
51	// diverges from the seed-42 output (some seeds may coincidentally match).
52	sensitive := false
53	for _, s := range []uint64{1, 7, 13, 12345, 8675309} {
54		if strings.Join(c.Generate(8, s), " ") != a {
55			sensitive = true
56			break
57		}
58	}
59	uassert.True(t, sensitive, "output varies with the seed")
60
61	// non-positive n and empty corpus both yield nothing
62	uassert.Equal(t, 0, len(c.Generate(0, 1)), "n<=0 yields no words")
63	empty := New()
64	uassert.Equal(t, 0, len(empty.Generate(10, 1)), "empty corpus yields no words")
65}
66
67func TestStatsAndIterate(t *testing.T) {
68	c := New()
69	c.Build("a b a b a b")
70
71	words, prefixes := c.Stats()
72	uassert.Equal(t, 6, words, "total words")
73	uassert.Equal(t, 4, prefixes, "distinct prefixes")
74
75	seen := 0
76	stopped := c.Iterate(func(prefix string, suffixes []string) bool {
77		uassert.True(t, len(suffixes) > 0, "each prefix has suffixes")
78		seen++
79		return false
80	})
81	uassert.Equal(t, 4, seen, "iterated over every prefix")
82	uassert.False(t, stopped, "ran to completion")
83}