[BAEL-16045] - Moved code to java-string-2

java-numbers/src/test/java/com/baeldung/maths/RoundUnitTest.java

@@ -0,0 +1,71 @@
+package com.baeldung.maths;
+
+import org.apache.commons.math3.util.Precision;
+import org.decimal4j.util.DoubleRounder;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class RoundUnitTest {
+    private double value = 2.03456d;
+    private int places = 2;
+    private double delta = 0.0d;
+    private double expected = 2.03d;
+
+    @Test
+    public void givenDecimalNumber_whenRoundToNDecimalPlaces_thenGetExpectedResult() {   
+        Assert.assertEquals(expected, Round.round(value, places), delta);
+        Assert.assertEquals(expected, Round.roundNotPrecise(value, places), delta);
+        Assert.assertEquals(expected, Round.roundAvoid(value, places), delta);
+        Assert.assertEquals(expected, Precision.round(value, places), delta);
+        Assert.assertEquals(expected, DoubleRounder.round(value, places), delta);
+        
+        places = 3;
+        expected = 2.035d;
+        
+        Assert.assertEquals(expected, Round.round(value, places), delta);
+        Assert.assertEquals(expected, Round.roundNotPrecise(value, places), delta);
+        Assert.assertEquals(expected, Round.roundAvoid(value, places), delta);
+        Assert.assertEquals(expected, Precision.round(value, places), delta);
+        Assert.assertEquals(expected, DoubleRounder.round(value, places), delta);
+        
+        value = 1000.0d;
+        places = 17;
+        expected = 1000.0d;
+        
+        Assert.assertEquals(expected, Round.round(value, places), delta);
+        Assert.assertEquals(expected, Round.roundNotPrecise(value, places), delta);
+        Assert.assertNotEquals(expected, Round.roundAvoid(value, places), delta); // Returns: 92.23372036854776 !
+        Assert.assertEquals(expected, Precision.round(value, places), delta);
+        Assert.assertEquals(expected, DoubleRounder.round(value, places), delta);
+        
+        value = 256.025d;
+        places = 2;
+        expected = 256.03d;
+        
+        Assert.assertEquals(expected, Round.round(value, places), delta);
+        Assert.assertNotEquals(expected, Round.roundNotPrecise(value, places), delta); // Returns: 256.02 !
+        Assert.assertNotEquals(expected, Round.roundAvoid(value, places), delta); // Returns: 256.02 !
+        Assert.assertEquals(expected, Precision.round(value, places), delta);
+        Assert.assertNotEquals(expected, DoubleRounder.round(value, places), delta); // Returns: 256.02 !
+        
+        value = 260.775d; 
+        places = 2;
+        expected = 260.78d;
+        
+        Assert.assertEquals(expected, Round.round(value, places), delta);
+        Assert.assertNotEquals(expected, Round.roundNotPrecise(value, places), delta); // Returns: 260.77 !
+        Assert.assertNotEquals(expected, Round.roundAvoid(value, places), delta); // Returns: 260.77 !
+        Assert.assertEquals(expected, Precision.round(value, places), delta);
+        Assert.assertNotEquals(expected, DoubleRounder.round(value, places), delta); // Returns: 260.77 !
+        
+        value = 90080070060.1d;
+        places = 9;
+        expected = 90080070060.1d;
+        
+        Assert.assertEquals(expected, Round.round(value, places), delta);
+        Assert.assertEquals(expected, Round.roundNotPrecise(value, places), delta);
+        Assert.assertNotEquals(expected, Round.roundAvoid(value, places), delta); // Returns: 9.223372036854776E9 !
+        Assert.assertEquals(expected, Precision.round(value, places), delta);
+        Assert.assertEquals(expected, DoubleRounder.round(value, places), delta);
+    }
+}