Create StringAppenderTest

kala-base/src/main/java/kala/text/StringAppender.java

@@ -17,16 +17,13 @@
 
 import org.jetbrains.annotations.NotNull;
 
-import java.io.IOException;
-import java.io.Serial;
-import java.io.Serializable;
-import java.io.Writer;
+import java.io.*;
 import java.util.Formatter;
 import java.util.Locale;
 import java.util.Objects;
 
-
-public class StringAppender extends Writer implements Serializable {
+@SuppressWarnings("resource")
+public class StringAppender extends Writer implements Externalizable {
     @Serial
     private static final long serialVersionUID = 0L;
 
@@ -448,6 +445,17 @@ private void beforeAppend(int n) {
         builder.ensureCapacity(builder.length() + n);
     }
 
+    @Override
+    public void writeExternal(ObjectOutput out) throws IOException {
+        out.writeObject(builder.toString());
+    }
+
+    @Override
+    public void readExternal(ObjectInput in) throws IOException, ClassNotFoundException {
+        this.builder.setLength(0);
+        this.builder.append((String) in.readObject());
+    }
+
     @Override
     public String toString() {
         return builder.toString();

src/test/java/kala/text/StringAppenderTest.java

@@ -0,0 +1,30 @@
+/*
+ * Copyright 2024 Glavo
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package kala.text;
+
+import kala.SerializationUtils;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+public class StringAppenderTest {
+
+    @Test
+    public void serializeTest() throws Exception {
+        assertEquals("", SerializationUtils.writeAndRead(new StringAppender()).toString());
+        assertEquals("str", SerializationUtils.writeAndRead(new StringAppender("str")).toString());
+    }
+}