Add configurable sequence numbering command

tests/contract/sequence_placement_test.go

@@ -0,0 +1,76 @@
+package contract
+
+import (
+	"context"
+	"path/filepath"
+	"testing"
+
+	"github.com/rogeecn/renamer/internal/sequence"
+)
+
+func TestSequencePreviewWithPrefixPlacement(t *testing.T) {
+	tmp := t.TempDir()
+
+	createFile(t, filepath.Join(tmp, "cover.png"))
+	createFile(t, filepath.Join(tmp, "index.png"))
+
+	opts := sequence.DefaultOptions()
+	opts.WorkingDir = tmp
+	opts.Start = 10
+	opts.Placement = sequence.PlacementPrefix
+	opts.Separator = "-"
+
+	plan, err := sequence.Preview(context.Background(), opts, nil)
+	if err != nil {
+		t.Fatalf("preview error: %v", err)
+	}
+
+	expected := []string{"010-cover.png", "011-index.png"}
+	if len(plan.Candidates) != len(expected) {
+		t.Fatalf("expected %d candidates, got %d", len(expected), len(plan.Candidates))
+	}
+	for i, candidate := range plan.Candidates {
+		if candidate.ProposedPath != expected[i] {
+			t.Fatalf("candidate %d proposed %s, expected %s", i, candidate.ProposedPath, expected[i])
+		}
+	}
+
+	if plan.Config.Start != 10 {
+		t.Fatalf("expected config start 10, got %d", plan.Config.Start)
+	}
+	if plan.Config.Placement != sequence.PlacementPrefix {
+		t.Fatalf("expected prefix placement in config")
+	}
+}
+
+func TestSequencePreviewWithNumberPrefixLabel(t *testing.T) {
+	tmp := t.TempDir()
+
+	createFile(t, filepath.Join(tmp, "cover.png"))
+	createFile(t, filepath.Join(tmp, "index.png"))
+
+	ops := sequence.DefaultOptions()
+	ops.WorkingDir = tmp
+	ops.Placement = sequence.PlacementPrefix
+	ops.Separator = "-"
+	ops.NumberPrefix = "seq"
+
+	plan, err := sequence.Preview(context.Background(), ops, nil)
+	if err != nil {
+		t.Fatalf("preview error: %v", err)
+	}
+
+	expected := []string{"seq001-cover.png", "seq002-index.png"}
+	if len(plan.Candidates) != len(expected) {
+		t.Fatalf("expected %d candidates, got %d", len(expected), len(plan.Candidates))
+	}
+	for i, candidate := range plan.Candidates {
+		if candidate.ProposedPath != expected[i] {
+			t.Fatalf("candidate %d proposed %s, expected %s", i, candidate.ProposedPath, expected[i])
+		}
+	}
+
+	if warnings := plan.Summary.Warnings; len(warnings) != 0 {
+		t.Fatalf("expected no warnings, got %#v", warnings)
+	}
+}