test(log): expand handler, config, and metrics coverage

internal/service/logger_test.go

@@ -0,0 +1,62 @@
+package service
+
+import (
+	"context"
+	"expvar"
+	"fmt"
+	"strconv"
+	"testing"
+	"time"
+
+	"github.com/ez-api/ez-api/internal/model"
+	"gorm.io/driver/sqlite"
+	"gorm.io/gorm"
+)
+
+func TestLogWriterMetrics(t *testing.T) {
+	dsn := fmt.Sprintf("file:%s?mode=memory&cache=shared", t.Name())
+	db, err := gorm.Open(sqlite.Open(dsn), &gorm.Config{})
+	if err != nil {
+		t.Fatalf("open sqlite: %v", err)
+	}
+	if err := db.AutoMigrate(&model.LogRecord{}); err != nil {
+		t.Fatalf("migrate: %v", err)
+	}
+
+	startBatch := getExpvarInt(t, "log_write_batch_total")
+	startDropped := getExpvarInt(t, "log_queue_dropped_total")
+
+	dropWriter := NewLogWriter(db, 1, 10, time.Second)
+	dropWriter.Write(model.LogRecord{ModelName: "m1", StatusCode: 200})
+	dropWriter.Write(model.LogRecord{ModelName: "m2", StatusCode: 200})
+
+	writer := NewLogWriter(db, 10, 1, 10*time.Millisecond)
+	ctx, cancel := context.WithCancel(context.Background())
+	t.Cleanup(cancel)
+	writer.Start(ctx)
+	writer.Write(model.LogRecord{ModelName: "m3", StatusCode: 200})
+
+	time.Sleep(50 * time.Millisecond)
+	cancel()
+
+	if got := getExpvarInt(t, "log_write_batch_total"); got <= startBatch {
+		t.Fatalf("expected batch counter to increase, start=%d got=%d", startBatch, got)
+	}
+	if got := getExpvarInt(t, "log_queue_dropped_total"); got <= startDropped {
+		t.Fatalf("expected dropped counter to be >= start, start=%d got=%d", startDropped, got)
+	}
+}
+
+func getExpvarInt(t *testing.T, name string) int64 {
+	t.Helper()
+	v := expvar.Get(name)
+	if v == nil {
+		t.Fatalf("expvar %s not found", name)
+	}
+	raw := v.String()
+	n, err := strconv.ParseInt(raw, 10, 64)
+	if err != nil {
+		t.Fatalf("parse expvar %s: %v", name, err)
+	}
+	return n
+}