Adding unit test for the array reversal function

Author: shroffk

core/formula/src/test/java/org/csstudio/apputil/formula/array/ArrayReversalFunctionTest.java

@@ -0,0 +1,54 @@
+package org.csstudio.apputil.formula.array;
+
+import org.epics.util.array.ArrayDouble;
+import org.epics.util.array.ListDouble;
+import org.epics.vtype.Alarm;
+import org.epics.vtype.Display;
+import org.epics.vtype.Time;
+import org.epics.vtype.VNumberArray;
+import org.epics.vtype.VType;
+import org.junit.jupiter.api.Test;
+
+import java.util.Arrays;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+class ArrayReversalFunctionTest {
+    private final ArrayReversalFunction function = new ArrayReversalFunction();
+
+    @Test
+    void testReverseTypicalArray() throws Exception {
+        VNumberArray input = VNumberArray.of(ArrayDouble.of(1, 2, 3, 4, 5), Alarm.none(), Time.now(), Display.none());
+        VType result = function.compute(input);
+        assertTrue(result instanceof VNumberArray);
+        double[] reversed = ((VNumberArray) result).getData().toArray(new double[input.getData().size()]);
+        assertArrayEquals(new double[]{5, 4, 3, 2, 1}, reversed, 1e-9);
+    }
+
+    @Test
+    void testReverseEmptyArray() throws Exception {
+        VNumberArray input = VNumberArray.of(ArrayDouble.of(), Alarm.none(), Time.now(), Display.none());
+        VType result = function.compute(input);
+        assertTrue(result instanceof VNumberArray);
+        double[] reversed = ((VNumberArray) result).getData().toArray(new double[input.getData().size()]);
+        assertArrayEquals(new double[]{}, reversed, 1e-9);
+    }
+
+    @Test
+    void testReverseSingleElementArray() throws Exception {
+        VNumberArray input = VNumberArray.of(ArrayDouble.of(42), Alarm.none(), Time.now(), Display.none());
+        VType result = function.compute(input);
+        assertTrue(result instanceof VNumberArray);
+        double[] reversed = ((VNumberArray) result).getData().toArray(new double[input.getData().size()]);
+        assertArrayEquals(new double[]{42}, reversed, 1e-9);
+    }
+
+    @Test
+    void testReverseNegativeNumbers() throws Exception {
+        VNumberArray input = VNumberArray.of(ArrayDouble.of(-1, -2, -3), Alarm.none(), Time.now(), Display.none());
+        VType result = function.compute(input);
+        assertTrue(result instanceof VNumberArray);
+        double[] reversed = ((VNumberArray) result).getData().toArray(new double[input.getData().size()]);
+        assertArrayEquals(new double[]{-3, -2, -1}, reversed, 1e-9);
+    }
+}