1 files changed, 39 insertions, 0 deletions
diff --git a/internal/tui/eventstream/export_test.go b/internal/tui/eventstream/export_test.go
index f398fce..6cea2b1 100644
--- a/internal/tui/eventstream/export_test.go
+++ b/internal/tui/eventstream/export_test.go
@@ -1,6 +1,8 @@
 package eventstream
 
 import (
+	"bytes"
+	"encoding/csv"
 	"os"
 	"path/filepath"
 	"reflect"
@@ -196,6 +198,43 @@ func TestExportRowsToCSVPathTraversal(t *testing.T) {
 	_ = traversal // silence unused-variable warning
 }
 
+func TestWriteStreamCSVAppendsFamilyColumn(t *testing.T) {
+	var buf bytes.Buffer
+	rows := []StreamEvent{{
+		Seq:        7,
+		TimeNs:     100,
+		GapNs:      3,
+		DurationNs: 5,
+		Comm:       "worker",
+		PID:        10,
+		TID:        11,
+		Syscall:    "socketpair",
+		FD:         4,
+		RetVal:     0,
+		Bytes:      0,
+		FileName:   "/tmp/sock",
+		IsError:    false,
+		Family:     "Network",
+	}}
+	fail := func(err error) (string, error) { return "", err }
+
+	if err := writeStreamCSV(csv.NewWriter(&buf), rows, fail); err != nil {
+		t.Fatalf("writeStreamCSV() error = %v", err)
+	}
+
+	records, err := csv.NewReader(bytes.NewReader(buf.Bytes())).ReadAll()
+	if err != nil {
+		t.Fatalf("read CSV: %v", err)
+	}
+	wantHeader := []string{"seq", "time_ns", "gap_ns", "latency_ns", "comm", "pid", "tid", "syscall", "fd", "ret", "bytes", "file", "error", "family"}
+	if !reflect.DeepEqual(records[0], wantHeader) {
+		t.Fatalf("header = %#v, want %#v", records[0], wantHeader)
+	}
+	if records[1][8] != "4" || records[1][12] != "false" || records[1][13] != "Network" {
+		t.Fatalf("family should be appended without shifting legacy columns, got %#v", records[1])
+	}
+}
+
 // TestShellSplitVariousCases covers the tokenizer with a table-driven approach.
 func TestShellSplitVariousCases(t *testing.T) {
 	cases := []struct {