Refactor MTProxy checker to support multiple DC probing with enhanced timeout handling. Update README and Docker documentation to include new -dc-ids flag for sequential DC checks, clarify exit codes, and improve error reporting for each DC. Adjust logic in checkOneLine and related functions to aggregate results from multiple DCs, ensuring robust performance and clearer output.

internal/dclist/dclist_test.go

@@ -0,0 +1,24 @@
+package dclist
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestParseList(t *testing.T) {
+	got, err := ParseList("")
+	if err != nil || got != nil {
+		t.Fatalf("empty: got %v err %v", got, err)
+	}
+	got, err = ParseList(" 1 , 2 , 5 ")
+	if err != nil || !reflect.DeepEqual(got, []int16{1, 2, 5}) {
+		t.Fatalf("1,2,5: got %v err %v", got, err)
+	}
+	got, err = ParseList("-1")
+	if err != nil || !reflect.DeepEqual(got, []int16{-1}) {
+		t.Fatalf("-1: got %v err %v", got, err)
+	}
+	if _, err := ParseList("foo"); err == nil {
+		t.Fatal("expected error")
+	}
+}