Add output validation against a defined JSON schema

internal/builtin/output.go

@@ -6,8 +6,8 @@ import (
 	"os"
 
 	"gitea.maximumdirect.net/eric/seriatim/internal/config"
-	"gitea.maximumdirect.net/eric/seriatim/internal/model"
 	"gitea.maximumdirect.net/eric/seriatim/internal/report"
+	"gitea.maximumdirect.net/eric/seriatim/schema"
 )
 
 type jsonOutputWriter struct{}
@@ -16,7 +16,7 @@ func (jsonOutputWriter) Name() string {
 	return "json"
 }
 
-func (jsonOutputWriter) Write(ctx context.Context, out model.FinalTranscript, rpt report.Report, cfg config.Config) ([]report.Event, error) {
+func (jsonOutputWriter) Write(ctx context.Context, out schema.Transcript, rpt report.Report, cfg config.Config) ([]report.Event, error) {
 	if err := ctx.Err(); err != nil {
 		return nil, err
 	}
@@ -34,6 +34,6 @@ func (jsonOutputWriter) Write(ctx context.Context, out model.FinalTranscript, rp
 	}
 
 	return []report.Event{
-		report.Info("output", "json", "wrote placeholder transcript JSON"),
+		report.Info("output", "json", "wrote transcript JSON"),
 	}, nil
 }

internal/builtin/postprocess.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 
+	"gitea.maximumdirect.net/eric/seriatim/internal/artifact"
 	"gitea.maximumdirect.net/eric/seriatim/internal/autocorrect"
 	"gitea.maximumdirect.net/eric/seriatim/internal/backchannel"
 	"gitea.maximumdirect.net/eric/seriatim/internal/coalesce"
@@ -12,6 +13,7 @@ import (
 	"gitea.maximumdirect.net/eric/seriatim/internal/model"
 	"gitea.maximumdirect.net/eric/seriatim/internal/overlap"
 	"gitea.maximumdirect.net/eric/seriatim/internal/report"
+	"gitea.maximumdirect.net/eric/seriatim/schema"
 )
 
 type noopPostprocessor struct {
@@ -52,6 +54,27 @@ func (assignIDs) Process(ctx context.Context, in model.MergedTranscript, cfg con
 	}, nil
 }
 
+type validateOutput struct{}
+
+func (validateOutput) Name() string {
+	return "validate-output"
+}
+
+func (validateOutput) Process(ctx context.Context, in model.MergedTranscript, cfg config.Config) (model.MergedTranscript, []report.Event, error) {
+	if err := ctx.Err(); err != nil {
+		return model.MergedTranscript{}, nil, err
+	}
+
+	transcript := artifact.FromMerged(cfg, in)
+	if err := schema.ValidateTranscript(transcript); err != nil {
+		return model.MergedTranscript{}, nil, fmt.Errorf("validate-output: %w", err)
+	}
+
+	return in, []report.Event{
+		report.Info("postprocessing", "validate-output", fmt.Sprintf("validated %d output segment(s)", len(in.Segments))),
+	}, nil
+}
+
 type detectOverlaps struct{}
 
 func (detectOverlaps) Name() string {

internal/builtin/postprocess_test.go

@@ -0,0 +1,60 @@
+package builtin
+
+import (
+	"context"
+	"strings"
+	"testing"
+
+	"gitea.maximumdirect.net/eric/seriatim/internal/config"
+	"gitea.maximumdirect.net/eric/seriatim/internal/model"
+)
+
+func TestValidateOutputSucceedsAfterAssignIDs(t *testing.T) {
+	merged := model.MergedTranscript{
+		Segments: []model.Segment{
+			{Source: "input.json", Speaker: "Alice", Start: 1, End: 2, Text: "hello"},
+			{Source: "input.json", Speaker: "Alice", Start: 3, End: 4, Text: "again"},
+		},
+	}
+
+	withIDs, _, err := assignIDs{}.Process(context.Background(), merged, testConfig())
+	if err != nil {
+		t.Fatalf("assign IDs: %v", err)
+	}
+	got, events, err := validateOutput{}.Process(context.Background(), withIDs, testConfig())
+	if err != nil {
+		t.Fatalf("validate output: %v", err)
+	}
+	if len(got.Segments) != 2 {
+		t.Fatalf("segment count = %d, want 2", len(got.Segments))
+	}
+	if len(events) != 1 || !strings.Contains(events[0].Message, "validated 2 output segment(s)") {
+		t.Fatalf("events = %#v", events)
+	}
+}
+
+func TestValidateOutputFailsBeforeAssignIDs(t *testing.T) {
+	merged := model.MergedTranscript{
+		Segments: []model.Segment{
+			{Source: "input.json", Speaker: "Alice", Start: 1, End: 2, Text: "hello"},
+		},
+	}
+
+	_, _, err := validateOutput{}.Process(context.Background(), merged, testConfig())
+	if err == nil {
+		t.Fatal("expected validation error")
+	}
+	if !strings.Contains(err.Error(), "segment 0 has id 0; want 1") {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}
+
+func testConfig() config.Config {
+	return config.Config{
+		InputReader:           config.DefaultInputReader,
+		InputFiles:            []string{"input.json"},
+		PreprocessingModules:  []string{"validate-raw", "normalize-speakers", "trim-text"},
+		PostprocessingModules: []string{"assign-ids", "validate-output"},
+		OutputModules:         []string{"json"},
+	}
+}

internal/builtin/registry.go

@@ -17,7 +17,7 @@ func NewRegistry() *pipeline.Registry {
 	registry.RegisterPostprocessor(fillerPostprocessor{})
 	registry.RegisterPostprocessor(coalescePostprocessor{})
 	registry.RegisterPostprocessor(assignIDs{})
-	registry.RegisterPostprocessor(noopPostprocessor{name: "validate-output"})
+	registry.RegisterPostprocessor(validateOutput{})
 	registry.RegisterPostprocessor(autocorrectPostprocessor{})
 	registry.RegisterOutputWriter(jsonOutputWriter{})