internal/config/builder_test.go: adding test for config with flags

internal/config/builder_test.go

@@ -75,6 +75,79 @@ redis:
 	require.Equal(t, &expected, cfg)
 }
 
+func TestBuilder_ConfigWithFlags(t *testing.T) {
+	expected := Config{
+		Name:         "ship-reader-1",
+		Api:          "https://api.example.com",
+		MessageCodec: "msgpack",
+		Log: log.Config{
+			Filename:    "mylog.log",
+			Directory:   "/var/log",
+			MaxFileSize: 200,
+			MaxTime:     30 * time.Minute,
+		},
+		Ship: ShipConfig{
+			Url:                 "127.0.0.1:8089",
+			StartBlockNum:       23671836,
+			EndBlockNum:         23872222,
+			IrreversibleOnly:    true,
+			MaxMessagesInFlight: 1337,
+		},
+		Telegram: TelegramConfig{
+			Id:      "110201543:AAHdqTcvCH1vGWJxfSeofSAs0K5PALDsaw",
+			Channel: -123456789,
+		},
+		Redis: RedisConfig{
+			Addr:     "localhost:6379",
+			User:     "userfromcli",
+			Password: "passwd",
+			DB:       4,
+			Prefix:   "some::ship",
+		},
+	}
+
+	builder := NewBuilder()
+	builder.SetSource(bytes.NewBuffer([]byte(`
+name: "ship-reader-1"
+api: "http://127.0.0.1:8080"
+message_codec: "mojibake"
+log:
+  filename: some_file.log
+  directory: /path/to/whatever
+  maxtime: 30m
+  maxfilesize: 200b
+ship:
+  url: "127.0.0.1:8089"
+  irreversible_only: true
+  max_messages_in_flight: 1337
+  start_block_num: 23671836
+  end_block_num: 23872222
+telegram:
+  id: "110201543:AAHdqTcvCH1vGWJxfSeofSAs0K5PALDsaw"
+  channel: -123456789
+redis:
+  addr: "localhost:6379"
+  user: "myuser"
+  password: "passwd"
+  db: 4
+  prefix: "some::ship"
+`)))
+
+	flags := GetFlags()
+
+	require.NoError(t, flags.Set("url", "https://api.example.com"))
+	require.NoError(t, flags.Set("codec", "msgpack"))
+	require.NoError(t, flags.Set("log", "/var/log/mylog.log"))
+	require.NoError(t, flags.Set("redis-user", "userfromcli"))
+
+	builder.SetFlags(flags)
+
+	cfg, err := builder.Build()
+
+	require.NoError(t, err)
+	require.Equal(t, &expected, cfg)
+}
+
 func TestBuilder_NilSource(t *testing.T) {
 	cfg, err := NewBuilder().Build()
 	require.Nil(t, cfg)