Add specific test file for fixing issues

issue_test.go

@@ -0,0 +1,31 @@
+package dns
+
+import "testing"
+
+// Tests that solve that a specific issue has been solved.
+
+func TestTCPRtt(t *testing.T) {
+	m := new(Msg)
+	m.RecursionDesired = true
+	m.SetQuestion("example.org.", TypeA)
+
+	c := &Client{}
+	in, rtt, err := c.Exchange(m, "8.8.4.4:53")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if rtt == 0 {
+		t.Fatalf("expecting non zero rtt, got zero")
+	}
+	t.Logf("%s", in)
+
+	c.Net = "tcp"
+	in, rtt, err = c.Exchange(m, "8.8.4.4:53")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if rtt == 0 {
+		t.Fatalf("expecting non zero rtt, got zero")
+	}
+	t.Logf("%s", in)
+}