Files
relata/internal/chunking/chunking_test.go
T
2026-08-11 10:40:10 +01:00

243 lines
7.7 KiB
Go

package chunking
import (
"strings"
"testing"
"github.com/andydixon/relata/internal/parsing"
)
func parse(t *testing.T, mime, body string) *parsing.Document {
t.Helper()
doc, err := parsing.Parse(parsing.Input{Data: []byte(body), MIMEType: mime})
if err != nil {
t.Fatalf("parse: %v", err)
}
return doc
}
// Offsets must always address the chunk's own text, or every downstream
// source reference (claims, entity mentions, excerpts) silently points at the
// wrong bytes.
func assertOffsetsValid(t *testing.T, doc *parsing.Document, r Result) {
t.Helper()
for _, c := range r.Chunks {
if c.Start < 0 || c.End > len(doc.Text) || c.Start > c.End {
t.Fatalf("chunk %d has out-of-range offsets [%d,%d) for text of %d bytes",
c.Sequence, c.Start, c.End, len(doc.Text))
}
if got := doc.Text[c.Start:c.End]; got != c.Text {
t.Fatalf("chunk %d text does not match its offsets:\n got: %q\nwant: %q", c.Sequence, c.Text, got)
}
}
}
func TestShortDocumentIsNotSplit(t *testing.T) {
body := "The delivery date moved to 14 March. Ops confirmed by email."
doc := parse(t, "text/plain", body)
r := Split(doc, Options{MaxChars: 400, MinSplitChars: 900})
if len(r.Chunks) != 1 {
t.Fatalf("short note should stay whole, got %d chunks", len(r.Chunks))
}
if r.Chunks[0].Text != body {
t.Fatalf("chunk text was altered:\n got %q\nwant %q", r.Chunks[0].Text, body)
}
assertOffsetsValid(t, doc, r)
}
func TestSplitsOnMarkdownHeadings(t *testing.T) {
body := "# Delivery policy\n\n" + strings.Repeat("Deliveries run on weekdays only. ", 12) +
"\n\n## Revised schedule\n\n" + strings.Repeat("The revised date is 14 March 2025. ", 12) +
"\n\n## Contact\n\n" + strings.Repeat("Contact operations for exceptions. ", 12)
doc := parse(t, "text/markdown", body)
r := Split(doc, Options{MaxChars: 900, TargetChars: 500, MinChars: 120, MinSplitChars: 400})
if len(r.Chunks) < 3 {
t.Fatalf("expected a chunk per section, got %d", len(r.Chunks))
}
assertOffsetsValid(t, doc, r)
// The heading that opens a section must travel with that section's body.
found := false
for _, c := range r.Chunks {
if strings.Contains(c.Text, "## Revised schedule") && strings.Contains(c.Text, "14 March 2025") {
found = true
}
}
if !found {
t.Fatal("heading was separated from the body it introduces")
}
}
func TestHeadingRecordedAsChunkContext(t *testing.T) {
body := "# Contract terms\n\n" + strings.Repeat("Payment is due in 30 days. ", 30) +
"\n\n## Penalties\n\n" + strings.Repeat("Late payment attracts interest. ", 30)
doc := parse(t, "text/markdown", body)
r := Split(doc, Options{MaxChars: 600, TargetChars: 400, MinChars: 100, MinSplitChars: 300})
var haveSection bool
for _, c := range r.Chunks {
if c.Section != "" || c.Heading != "" {
haveSection = true
}
}
if !haveSection {
t.Fatal("no chunk retained section or heading context")
}
}
func TestOversizedBlockIsSplitAtSentenceBoundaries(t *testing.T) {
// One paragraph, no blank lines, far larger than the ceiling.
body := strings.Repeat("This sentence is a self-contained statement of fact. ", 200)
doc := parse(t, "text/plain", body)
r := Split(doc, Options{MaxChars: 500, TargetChars: 350, MinChars: 100, MinSplitChars: 400})
if len(r.Chunks) < 5 {
t.Fatalf("oversized paragraph should be divided, got %d chunks", len(r.Chunks))
}
assertOffsetsValid(t, doc, r)
for _, c := range r.Chunks {
core := c.End - c.Start - c.OverlapChars
if core > 500 {
t.Fatalf("chunk %d core span %d exceeds the ceiling of 500", c.Sequence, core)
}
}
// Splitting at sentence ends means most chunks begin with a capital letter.
capitals := 0
for _, c := range r.Chunks {
trimmed := strings.TrimSpace(c.Text)
if trimmed != "" && trimmed[0] >= 'A' && trimmed[0] <= 'Z' {
capitals++
}
}
if capitals*2 < len(r.Chunks) {
t.Fatalf("only %d/%d chunks start at a sentence boundary", capitals, len(r.Chunks))
}
}
func TestOverlapIsCarriedFromPreviousChunk(t *testing.T) {
body := strings.Repeat("Alpha beta gamma delta epsilon zeta. ", 100)
doc := parse(t, "text/plain", body)
r := Split(doc, Options{MaxChars: 400, TargetChars: 300, MinChars: 80, OverlapChars: 60, MinSplitChars: 300})
if len(r.Chunks) < 2 {
t.Fatalf("need multiple chunks to test overlap, got %d", len(r.Chunks))
}
assertOffsetsValid(t, doc, r)
for i := 1; i < len(r.Chunks); i++ {
if r.Chunks[i].OverlapChars <= 0 {
t.Fatalf("chunk %d records no overlap", i)
}
// The overlap must genuinely come from the preceding chunk.
prefix := r.Chunks[i].Text[:r.Chunks[i].OverlapChars]
if !strings.Contains(r.Chunks[i-1].Text, strings.TrimSpace(prefix)) {
t.Fatalf("chunk %d overlap %q is not present in chunk %d", i, prefix, i-1)
}
}
}
func TestChunkCountIsBounded(t *testing.T) {
body := strings.Repeat("Paragraph.\n\n", 5000)
doc := parse(t, "text/plain", body)
r := Split(doc, Options{MaxChars: 100, TargetChars: 60, MinChars: 10, MaxChunks: 25, MinSplitChars: 50})
if len(r.Chunks) > 25 {
t.Fatalf("MaxChunks not enforced: got %d", len(r.Chunks))
}
if !r.Truncated {
t.Fatal("truncation was not reported, so the user would not learn content went unindexed")
}
}
func TestChunksCoverDocumentWithoutGaps(t *testing.T) {
body := strings.Repeat("Sentence one here. Sentence two here.\n\n", 60)
doc := parse(t, "text/plain", body)
r := Split(doc, Options{MaxChars: 400, TargetChars: 250, MinChars: 80, MinSplitChars: 300})
assertOffsetsValid(t, doc, r)
// Ignoring overlap, consecutive core spans must be contiguous or adjacent
// across whitespace: no document content may be dropped.
prevEnd := 0
for _, c := range r.Chunks {
coreStart := c.Start + c.OverlapChars
gap := doc.Text[min(prevEnd, len(doc.Text)):min(coreStart, len(doc.Text))]
if strings.TrimSpace(gap) != "" {
t.Fatalf("content dropped between chunks: %q", gap)
}
prevEnd = c.End
}
if strings.TrimSpace(doc.Text[min(prevEnd, len(doc.Text)):]) != "" {
t.Fatal("trailing content was not chunked")
}
}
func TestEmptyDocumentProducesNoChunks(t *testing.T) {
doc := parse(t, "text/plain", " \n\n \t ")
if r := Split(doc, Options{}); len(r.Chunks) != 0 {
t.Fatalf("whitespace-only document produced %d chunks", len(r.Chunks))
}
}
func TestHashIsStableAndContentDependent(t *testing.T) {
a := HashText("the revised delivery date is 14 March")
b := HashText("the revised delivery date is 14 March")
c := HashText("the revised delivery date is 15 March")
if a != b {
t.Fatal("hash is not deterministic")
}
if a == c {
t.Fatal("different content produced the same hash")
}
if len(a) != 64 {
t.Fatalf("expected hex sha-256, got %d chars", len(a))
}
}
func TestUTF8IsNeverSplitMidRune(t *testing.T) {
body := strings.Repeat("Ünïcödé wörds with ümlauts and émojis 🌍 everywhere. ", 100)
doc := parse(t, "text/plain", body)
r := Split(doc, Options{MaxChars: 300, TargetChars: 200, MinChars: 60, OverlapChars: 40, MinSplitChars: 200})
assertOffsetsValid(t, doc, r)
for _, c := range r.Chunks {
if !isValidUTF8(c.Text) {
t.Fatalf("chunk %d contains invalid UTF-8", c.Sequence)
}
}
}
func isValidUTF8(s string) bool {
for _, r := range s {
if r == '�' {
return false
}
}
return true
}
func TestJSONChunkingRespectsObjectBoundaries(t *testing.T) {
var sb strings.Builder
sb.WriteString(`{"records":[`)
for i := 0; i < 60; i++ {
if i > 0 {
sb.WriteString(",")
}
sb.WriteString(`{"id":`)
sb.WriteString(strings.TrimSpace(strings.Repeat("1", 2)))
sb.WriteString(`,"note":"delivery scheduled","owner":"Example Ltd"}`)
}
sb.WriteString(`]}`)
doc := parse(t, "application/json", sb.String())
r := Split(doc, Options{MaxChars: 400, TargetChars: 250, MinChars: 80, MinSplitChars: 300})
if len(r.Chunks) < 2 {
t.Fatalf("expected the JSON document to be divided, got %d chunks", len(r.Chunks))
}
assertOffsetsValid(t, doc, r)
}