refactored example code

libraries/src/test/java/com/baeldung/commons/collections/SetUtilsUnitTest.java

@@ -4,6 +4,7 @@ import org.apache.commons.collections4.SetUtils;
 import org.apache.commons.collections4.set.TransformedSet;
 import org.junit.Test;
 
+import java.util.Arrays;
 import java.util.HashSet;
 import java.util.Set;
 
@@ -18,55 +19,34 @@ public class SetUtilsUnitTest {
     @Test(expected = IllegalArgumentException.class)
     public void givenSetAndPredicate_whenPredicatedSet_thenValidateSet_and_throw_IllegalArgumentException() {
         Set<String> sourceSet = new HashSet<>();
-        sourceSet.add("London");
+        sourceSet.addAll(Arrays.asList("London", "Lagos", "Err Source1"));
-        sourceSet.add("Lagos");
-        sourceSet.add("Error Source1");
         Set<String> validatingSet
           = SetUtils.predicatedSet(sourceSet, (s) -> s.startsWith("L"));
-        validatingSet.add("Error Source2");
+        validatingSet.add("Err Source2");
     }
 
     @Test
     public void givenTwoSets_whenDifference_thenSetView() {
-        Set<Integer> a = new HashSet<>();
+        Set<Integer> a = new HashSet<>(Arrays.asList(1,2,5));
-        a.add(1);
+        Set<Integer> b = new HashSet<>(Arrays.asList(1,2));
-        a.add(2);
-        a.add(5);
-        Set<Integer> b = new HashSet<>();
-        b.add(1);
-        b.add(2);
         SetUtils.SetView<Integer> result = SetUtils.difference(a, b);
         assertTrue(result.size() == 1 && result.contains(5));
     }
 
     @Test
     public void givenTwoSets_whenUnion_thenUnionResult() {
-        Set<Integer> a = new HashSet<>();
+        Set<Integer> a = new HashSet<>(Arrays.asList(1,2,5));
-        a.add(1);
+        Set<Integer> b = new HashSet<>(Arrays.asList(1,2));
-        a.add(2);
+        Set<Integer> expected = new HashSet<>(Arrays.asList(1,2,5));
-        a.add(5);
-        Set<Integer> b = new HashSet<>();
-        b.add(1);
-        b.add(2);
-        Set<Integer> expected = new HashSet<>();
-        expected.addAll(a);
-        expected.addAll(b);
         SetUtils.SetView<Integer> union = SetUtils.union(a, b);
         assertTrue(SetUtils.isEqualSet(expected, union));
     }
 
     @Test
     public void givenTwoSets_whenIntersection_thenIntersectionResult() {
-        Set<Integer> a = new HashSet<>();
+        Set<Integer> a = new HashSet<>(Arrays.asList(1,2,5));
-        a.add(1);
+        Set<Integer> b = new HashSet<>(Arrays.asList(1,2));
-        a.add(2);
+        Set<Integer> expected = new HashSet<>(Arrays.asList(1,2));
-        a.add(5);
-        Set<Integer> b = new HashSet<>();
-        b.add(1);
-        b.add(2);
-        Set<Integer> expected = new HashSet<>();
-        expected.add(1);
-        expected.add(2);
         SetUtils.SetView<Integer> intersect = SetUtils.intersection(a, b);
         assertTrue(SetUtils.isEqualSet(expected, intersect));
     }
@@ -77,8 +57,7 @@ public class SetUtilsUnitTest {
         a.add(2);
         assertEquals(a.toArray()[0], 4);
 
-        Set<Integer> source = new HashSet<>();
+        Set<Integer> source = new HashSet<>(Arrays.asList(1));
-        source.add(1);
         Set<Integer> newSet = TransformedSet.transformedSet(source, (e) -> e * 2);
         assertEquals(newSet.toArray()[0], 2);
         assertEquals(source.toArray()[0], 2);
@@ -86,30 +65,19 @@ public class SetUtilsUnitTest {
 
     @Test
     public void givenTwoSet_whenDisjunction_thenDisjunctionSet() {
-        Set<Integer> a = new HashSet<>();
+        Set<Integer> a = new HashSet<>(Arrays.asList(1,2,5));
-        a.add(1);
+        Set<Integer> b = new HashSet<>(Arrays.asList(1,2,3));
-        a.add(2);
-        a.add(5);
-        Set<Integer> b = new HashSet<>();
-        b.add(1);
-        b.add(2);
-        b.add(3);
         SetUtils.SetView<Integer> result = SetUtils.disjunction(a, b);
         assertTrue(result.toSet().contains(5) && result.toSet().contains(3));
     }
 
     @Test
     public void givenSet_when_OrderedSet_thenMaintainElementOrder() {
-        Set<Integer> set = new HashSet<>();
+        Set<Integer> set = new HashSet<>(Arrays.asList(10,1,5));
-        set.add(10);
-        set.add(1);
-        set.add(5);
         System.out.println("unordered set: " + set);
 
         Set<Integer> orderedSet = SetUtils.orderedSet(new HashSet<>());
-        orderedSet.add(10);
+        orderedSet.addAll(Arrays.asList(10,1,5));
-        orderedSet.add(1);
-        orderedSet.add(5);
         System.out.println("ordered set = " + orderedSet);
     }
 }