Added new test for CharSequenceTranslator#with.

Author: TheRealHaui

src/test/java/org/apache/commons/text/translate/CharSequenceTranslatorTest.java

@@ -0,0 +1,58 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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
+ *
+ *      https://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 org.apache.commons.text.translate;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+import java.io.IOException;
+import java.io.Writer;
+
+import org.junit.jupiter.api.Test;
+
+
+class CharSequenceTranslatorTest {
+
+    //Used to count translate invocations
+    private int translateInvocationCounter;
+
+    @Test
+    void testWith() throws IOException {
+        CharSequenceTranslator charSequenceTranslatorOne = new TestCharSequenceTranslator();
+        CharSequenceTranslator charSequenceTranslatorTwo = new TestCharSequenceTranslator();
+        CharSequenceTranslator charSequenceTranslatorThree = new TestCharSequenceTranslator();
+
+        CharSequenceTranslator aggregatedTranslator = charSequenceTranslatorOne.with(charSequenceTranslatorTwo, charSequenceTranslatorThree);
+
+        aggregatedTranslator.translate("", 0, null);
+
+        assertTrue(aggregatedTranslator instanceof AggregateTranslator);
+        assertEquals(3, translateInvocationCounter);
+
+    }
+
+
+    private final class TestCharSequenceTranslator extends CharSequenceTranslator {
+        @Override
+        public int translate(final CharSequence input, final int index, final Writer writer) {
+            translateInvocationCounter++;
+            return 0;
+        }
+
+    }
+
+}