Files
tapir/internal/adapters/transcribe/gateway_test.go
mathiasandClaude Sonnet 5.5 0b807c6bcd feat(transcribe): the gateway sends language=sv, omits it for auto, and refuses anything else (#61)
The request used to hard-code language=sv for every upload, so a recording in another
language was decoded as Swedish. The language now comes from the context; no language in
the context is still sv.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
2026-10-04 22:26:13 +02:00

303 lines
12 KiB
Go

package transcribe_test
import (
"bytes"
"context"
"fmt"
"io"
"net/http"
"net/http/httptest"
"os"
"path/filepath"
"strings"
"testing"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
"git.d-ma.be/mathias/tapir/internal/adapters/transcribe"
"git.d-ma.be/mathias/tapir/internal/domain"
"git.d-ma.be/mathias/tapir/internal/errkind"
)
// The httptest server stands in for the LiteLLM gateway: it is the process
// boundary, so a fake here is legitimate. The JSON it returns mirrors what the
// real gateway returned for iguana/kb-whisper and berget/kb-whisper on 2026-10-01
// (docs/research/audio-length-ceiling-2026-10-01.md). All text is synthetic.
const verboseJSON = `{
"text": " God morgon allihopa.\n Vi går igenom läget.\n",
"language": "swedish",
"duration": 4.25,
"segments": [
{"id": 0, "start": 0.0, "end": 1.0, "text": " God morgon allihopa."},
{"id": 1, "start": 1.0, "end": 9.0, "text": " Vi går igenom läget."}
]
}`
func wavFile(t *testing.T, content string) string {
t.Helper()
p := filepath.Join(t.TempDir(), "a.wav")
require.NoError(t, os.WriteFile(p, []byte(content), 0o600))
return p
}
type seen struct {
method, path, auth, expect, contentType string
contentLength int64
transferEncoding []string
fields map[string]string
file string
fileField string
bodyLen int
}
// serve starts a gateway fake that records the request it received and replies
// with status and body.
func serve(t *testing.T, status int, reply string, got *seen) *httptest.Server {
t.Helper()
srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
if got != nil {
got.method, got.path = r.Method, r.URL.Path
got.auth = r.Header.Get("Authorization")
got.expect = r.Header.Get("Expect")
got.contentType = r.Header.Get("Content-Type")
got.contentLength = r.ContentLength
got.transferEncoding = r.TransferEncoding
raw, _ := io.ReadAll(r.Body)
got.bodyLen = len(raw)
r.Body = io.NopCloser(bytes.NewReader(raw))
require.NoError(t, r.ParseMultipartForm(32<<20))
got.fields = map[string]string{}
for k, v := range r.MultipartForm.Value {
got.fields[k] = v[0]
}
for field, fhs := range r.MultipartForm.File {
got.fileField = field
f, _ := fhs[0].Open()
b, _ := io.ReadAll(f)
got.file = string(b)
}
}
w.WriteHeader(status)
_, _ = io.WriteString(w, reply)
}))
t.Cleanup(srv.Close)
return srv
}
func TestGateway_SendsTheRequestTheGatewayExpects(t *testing.T) {
var got seen
srv := serve(t, 200, verboseJSON, &got)
g := transcribe.NewGateway(srv.URL+"/v1", "secret-key", "iguana/kb-whisper", srv.Client())
_, err := g.Transcribe(context.Background(), wavFile(t, "RIFF-synthetic-pcm"))
require.NoError(t, err)
assert.Equal(t, http.MethodPost, got.method)
assert.Equal(t, "/v1/audio/transcriptions", got.path)
assert.Equal(t, "Bearer secret-key", got.auth)
assert.Equal(t, "file", got.fileField, "the multipart field is `file`; `audio_file` is rejected as 'Invalid request'")
assert.Equal(t, "RIFF-synthetic-pcm", got.file)
assert.Equal(t, "iguana/kb-whisper", got.fields["model"])
assert.Equal(t, "verbose_json", got.fields["response_format"])
assert.Equal(t, "sv", got.fields["language"])
assert.Empty(t, got.expect, "no Expect: 100-continue: it trips the proxy for any body over 1 KB")
}
func TestGateway_SendsAKnownContentLengthNotChunked(t *testing.T) {
var got seen
srv := serve(t, 200, verboseJSON, &got)
g := transcribe.NewGateway(srv.URL+"/v1", "k", "m", srv.Client())
_, err := g.Transcribe(context.Background(), wavFile(t, "0123456789"))
require.NoError(t, err)
assert.Empty(t, got.transferEncoding, "a 90-minute WAV is ~170 MB: stream it with a computed length, not chunked and not buffered")
assert.Equal(t, int64(got.bodyLen), got.contentLength)
}
func TestGateway_NormalisesTheVerboseJSONResponse(t *testing.T) {
srv := serve(t, 200, verboseJSON, nil)
g := transcribe.NewGateway(srv.URL+"/v1", "k", "iguana/kb-whisper", srv.Client())
got, err := g.Transcribe(context.Background(), wavFile(t, "x"))
require.NoError(t, err)
assert.Equal(t, "God morgon allihopa. Vi går igenom läget.", got.Text)
assert.Equal(t, "iguana/kb-whisper", got.Endpoint, "the serving endpoint is part of the result")
assert.InDelta(t, 4.25, got.AudioSeconds, 1e-9)
assert.Equal(t, []domain.Segment{
{Start: 0, End: 1, Text: "God morgon allihopa."},
// The final segment ended at 9.0 s for 4.25 s of audio: whisper's last
// window can run past the end. Clamped to the audio duration.
{Start: 1, End: 4.25, Text: "Vi går igenom läget."},
}, got.Segments)
}
func TestGateway_ErrorsDoNotDependOnTheBody(t *testing.T) {
// {"error":"failed to process audio"} has had at least five distinct causes, so
// no code may branch on it. Two different bodies must be treated identically.
for _, reply := range []string{`{"error":"failed to process audio"}`, `{"error":"something else entirely"}`} {
srv := serve(t, 500, reply, nil)
g := transcribe.NewGateway(srv.URL+"/v1", "k", "m", srv.Client())
_, err := g.Transcribe(context.Background(), wavFile(t, "x"))
var se *transcribe.StatusError
require.ErrorAs(t, err, &se)
assert.Equal(t, 500, se.Code)
}
}
func TestGateway_AnEmptyTranscriptIsAFailureNotASuccess(t *testing.T) {
srv := serve(t, 200, `{"text":" ","language":"swedish","duration":3,"segments":[]}`, nil)
g := transcribe.NewGateway(srv.URL+"/v1", "k", "m", srv.Client())
_, err := g.Transcribe(context.Background(), wavFile(t, "x"))
assert.ErrorIs(t, err, transcribe.ErrEmptyTranscript)
}
func TestGateway_MalformedJSONIsAnError(t *testing.T) {
srv := serve(t, 200, `not json`, nil)
g := transcribe.NewGateway(srv.URL+"/v1", "k", "m", srv.Client())
_, err := g.Transcribe(context.Background(), wavFile(t, "x"))
assert.Error(t, err)
}
func TestGateway_MissingAudioFileIsAnError(t *testing.T) {
g := transcribe.NewGateway("http://127.0.0.1:1/v1", "k", "m", http.DefaultClient)
_, err := g.Transcribe(context.Background(), filepath.Join(t.TempDir(), "nope.wav"))
assert.Error(t, err)
}
// whisper.cpp wraps its output at ~60 characters, and a wrap can land INSIDE a word:
// the continuation segment has no leading space, the `text` field joins segments
// with newlines, and a segment can be a lone ".". Measured on real gateway output
// 2026-10-01: 7% of a one-hour recording's segments were such fragments. Joining by
// newline hands the chat model broken words ("nyt\nt"), so Text is rebuilt from the
// segments: a segment that begins with a space starts a new word, one that does not
// continues the previous one.
func TestGateway_RejoinsWordsWhisperCppSplitAcrossSegments(t *testing.T) {
reply := `{
"text": " Vi ligger just nu 12 procent över den ursprungliga kalkylen\n.\n Det kräver ett nyt\nt godkännande från beställaren.\n Framförallt på arbetspl\natsen.\n",
"language": "swedish", "duration": 20,
"segments": [
{"start": 0, "end": 4, "text": " Vi ligger just nu 12 procent över den ursprungliga kalkylen"},
{"start": 4, "end": 5, "text": "."},
{"start": 5, "end": 8, "text": " Det kräver ett nyt"},
{"start": 8, "end": 11, "text": "t godkännande från beställaren."},
{"start": 11, "end": 14, "text": " Framförallt på arbetspl"},
{"start": 14, "end": 16, "text": "atsen."}
]}`
srv := serve(t, 200, reply, nil)
g := transcribe.NewGateway(srv.URL+"/v1", "k", "iguana/kb-whisper", srv.Client())
got, err := g.Transcribe(context.Background(), wavFile(t, "x"))
require.NoError(t, err)
assert.Equal(t, "Vi ligger just nu 12 procent över den ursprungliga kalkylen. "+
"Det kräver ett nytt godkännande från beställaren. Framförallt på arbetsplatsen.", got.Text)
assert.Len(t, got.Segments, 6, "the timed segments are kept as the backend gave them (trimmed)")
assert.Equal(t, ".", got.Segments[1].Text)
}
func TestGateway_SentenceLevelSegmentsWithNoLeadingSpaceAreJoinedWithASpace(t *testing.T) {
// berget/kb-whisper returns whole sentences with no leading space; rebuilding by
// concatenation would glue them ("allihopa!Vi").
reply := `{"text": "God morgon allihopa!\nVi går igenom läget.", "language": "sv", "duration": 5,
"segments": [
{"start": 0.05, "end": 1.2, "text": "God morgon allihopa!"},
{"start": 1.6, "end": 4.2, "text": "Vi går igenom läget."}
]}`
srv := serve(t, 200, reply, nil)
g := transcribe.NewGateway(srv.URL+"/v1", "k", "berget/kb-whisper", srv.Client())
got, err := g.Transcribe(context.Background(), wavFile(t, "x"))
require.NoError(t, err)
assert.Equal(t, "God morgon allihopa! Vi går igenom läget.", got.Text)
}
func TestGateway_WithNoSegmentsTheTextFieldIsUsedWithWhitespaceCollapsed(t *testing.T) {
srv := serve(t, 200, `{"text": " Hej allihopa.\n Vi börjar. ", "duration": 3, "segments": []}`, nil)
g := transcribe.NewGateway(srv.URL+"/v1", "k", "m", srv.Client())
got, err := g.Transcribe(context.Background(), wavFile(t, "x"))
require.NoError(t, err)
assert.Equal(t, "Hej allihopa. Vi börjar.", got.Text)
}
func TestStatusError_ExposesItsCodeAsAKindAndNotItsSnippet(t *testing.T) {
err := fmt.Errorf("transcribe: %w", &transcribe.StatusError{Code: 502, Snippet: "echoed: Anders ansvarar"})
assert.Equal(t, "http_502", errkind.Of(err))
}
func TestGateway_AnErrorBodyIsBoundedToTwoHundredBytesInTheStatusError(t *testing.T) {
srv := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, _ *http.Request) {
w.WriteHeader(http.StatusInternalServerError)
_, _ = w.Write([]byte(strings.Repeat("x", 100_000)))
}))
defer srv.Close()
wav := filepath.Join(t.TempDir(), "a.wav")
require.NoError(t, os.WriteFile(wav, []byte("RIFF....WAVEfmt "), 0o600))
_, err := transcribe.NewGateway(srv.URL, "", "iguana/kb-whisper", srv.Client()).Transcribe(context.Background(), wav)
var se *transcribe.StatusError
require.ErrorAs(t, err, &se)
assert.LessOrEqual(t, len(se.Snippet), 200, "a gateway's whole body must not become part of an error")
}
// The language travels on the context (tapir#61); the request field is the only place it
// takes effect, so these observe the request the gateway fake received.
func TestGateway_SendsLanguageSvWhenTheContextCarriesNoneAndForSwedish(t *testing.T) {
for name, ctx := range map[string]context.Context{
"no language in the context": context.Background(),
"swedish": domain.WithLanguage(context.Background(), domain.LangSwedish),
} {
t.Run(name, func(t *testing.T) {
var got seen
srv := serve(t, 200, verboseJSON, &got)
g := transcribe.NewGateway(srv.URL+"/v1", "k", "iguana/kb-whisper", srv.Client())
_, err := g.Transcribe(ctx, wavFile(t, "RIFF-synthetic-pcm"))
require.NoError(t, err)
assert.Equal(t, "sv", got.fields["language"])
})
}
}
func TestGateway_OmitsTheLanguageFieldForAnAutoContextSoTheEngineDetectsIt(t *testing.T) {
var got seen
srv := serve(t, 200, verboseJSON, &got)
g := transcribe.NewGateway(srv.URL+"/v1", "k", "iguana/kb-whisper", srv.Client())
_, err := g.Transcribe(domain.WithLanguage(context.Background(), domain.LangAuto), wavFile(t, "RIFF-synthetic-pcm"))
require.NoError(t, err)
_, present := got.fields["language"]
assert.False(t, present, "an auto upload must not be forced to Swedish")
assert.Equal(t, "iguana/kb-whisper", got.fields["model"], "the rest of the request is unchanged")
}
func TestGateway_ALanguageOutsideTheClosedSetIsRefusedBeforeAnythingIsSent(t *testing.T) {
var got seen
srv := serve(t, 200, verboseJSON, &got)
g := transcribe.NewGateway(srv.URL+"/v1", "k", "iguana/kb-whisper", srv.Client())
_, err := g.Transcribe(domain.WithLanguage(context.Background(), domain.Language("en")), wavFile(t, "RIFF-synthetic-pcm"))
require.Error(t, err)
assert.Empty(t, got.method, "no request may reach the engine with a language the closed set does not hold")
}