added LengthExpressionTest

src/main/java/org/jd/core/v1/model/javasyntax/expression/LengthExpression.java

@@ -14,12 +14,12 @@ public class LengthExpression extends AbstractLineNumberExpression {
     private Expression expression;
 
     public LengthExpression(Expression expression) {
-        this.expression = expression;
+        this(UNKNOWN_LINE_NUMBER, expression);
     }
 
     public LengthExpression(int lineNumber, Expression expression) {
         super(lineNumber);
-        this.expression = expression;
+        this.setExpression(expression);
     }
 
     @Override

src/test/java/org/jd/core/v1/model/javasyntax/expression/LengthExpressionTest.java

@@ -0,0 +1,47 @@
+package org.jd.core.v1.model.javasyntax.expression;
+
+import org.jd.core.v1.model.javasyntax.type.ObjectType;
+import org.jd.core.v1.model.javasyntax.type.PrimitiveType;
+import org.jd.core.v1.service.converter.classfiletojavasyntax.visitor.TestVisitor;
+import org.junit.Test;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertTrue;
+
+public class LengthExpressionTest {
+
+    @Test
+    public void testLengthExpression() {
+        // Array expression
+        ObjectType type = (ObjectType) ObjectType.TYPE_PRIMITIVE_INT.createType(1);
+        String name = "array";
+        Expression expression = new LocalVariableReferenceExpression(type, name);
+        int lineNumber = 0;
+        Expression index = new IntegerConstantExpression(lineNumber, PrimitiveType.TYPE_INT, 0);
+        Expression arrayExpression = new ArrayExpression(lineNumber, expression, index);
+
+        LengthExpression lengthExpression = new LengthExpression(arrayExpression);
+
+        // Test getExpression
+        assertEquals(arrayExpression, lengthExpression.getExpression());
+
+        // Test getType
+        assertEquals(PrimitiveType.TYPE_INT, lengthExpression.getType());
+
+        // Test isLengthExpression
+        assertTrue(lengthExpression.isLengthExpression());
+
+        // Test toString
+        assertEquals("LengthExpression{ArrayExpression{LocalVariableReferenceExpression{type=ObjectType{I, dimension=1}, name=array}[IntegerConstantExpression{type=PrimitiveType{primitive=int}, value=0}]}}", lengthExpression.toString());
+
+        // Test copyTo
+        LengthExpression copiedExpression = (LengthExpression) lengthExpression.copyTo(20);
+        assertEquals(lengthExpression.getExpression(), copiedExpression.getExpression());
+        assertEquals(20, copiedExpression.getLineNumber());
+
+        // Test the accept method with a simple visitor
+        TestVisitor visitor = new TestVisitor();
+        copiedExpression.accept(visitor);
+        assertEquals(1, visitor.getLengthExpressionCount());
+    }
+}