[BAEL-1775] Getting size of Iterable in Java

core-java-collections/src/test/java/com/baeldung/java/iterable/IterableSizeTest.java

@@ -0,0 +1,59 @@
+package com.baeldung.java.iterable;
+
+import static org.junit.Assert.assertEquals;
+
+import java.sql.SQLException;
+import java.util.List;
+
+import org.junit.jupiter.api.Test;
+
+import com.google.common.collect.Lists;
+
+class IterableSizeTest {
+
+    private final List<String> list = Lists.newArrayList("Apple", "Orange", "Banana");
+
+    private Iterable data;
+
+    @Test
+    void whenUsingJava7_iterableOfCollectionType_thenCorrectSize() {
+
+        final int size = IterableSize.sizeUsingJava7(list);
+
+        assertEquals(3, size);
+    }
+
+    @Test
+    void whenUsingJava7_iterableNotOfCollectionType_thenCorrect() {
+
+        final SQLException exception = new SQLException();
+        exception.setNextException(new SQLException());
+        final int size = IterableSize.sizeUsingJava7(exception);
+
+        assertEquals(2, size);
+    }
+
+    @Test
+    void whenUsingJava8_thenCorrect() {
+
+        final long size = IterableSize.sizeUsingJava8(list);
+
+        assertEquals(3, size);
+    }
+
+    @Test
+    void whenUsingApacheCollections_thenCorrect() {
+
+        final int size = IterableSize.sizeUsingApacheCollections(list);
+
+        assertEquals(3, size);
+    }
+
+    @Test
+    void whenUsingGoogleGuava_thenCorrect() {
+
+        final int size = IterableSize.sizeUsingGoogleGuava(list);
+
+        assertEquals(3, size);
+    }
+}