add unit test showing bug

Author: d050150

document-readers/pdf-reader/src/test/java/org/springframework/ai/reader/pdf/layout/TextLineTest.java

@@ -0,0 +1,17 @@
+package org.springframework.ai.reader.pdf.layout;
+
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+
+
+class TextLineTest {
+
+	@Test
+	void testWriteCharacterAtIndex_BeginningOfNewLine() {
+		TextLine textLine = new TextLine(100);
+		Character character = new Character('A', 0, false, true, false, false);
+		textLine.writeCharacterAtIndex(character);
+		assertEquals("A" + " ".repeat(99), textLine.getLine());
+	}
+}