Migrate to JUnit5

lazy-loading/pom.xml

@@ -34,8 +34,13 @@
   <artifactId>lazy-loading</artifactId>
   <dependencies>
     <dependency>
-      <groupId>junit</groupId>
-      <artifactId>junit</artifactId>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-api</artifactId>
+      <scope>test</scope>
+    </dependency>
+    <dependency>
+      <groupId>org.junit.jupiter</groupId>
+      <artifactId>junit-jupiter-engine</artifactId>
       <scope>test</scope>
     </dependency>
   </dependencies>

lazy-loading/src/test/java/com/iluwatar/lazy/loading/AbstractHolderTest.java

@@ -22,11 +22,13 @@
  */
 package com.iluwatar.lazy.loading;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
-import static junit.framework.Assert.assertNotNull;
-import static junit.framework.Assert.assertSame;
-import static junit.framework.TestCase.assertNull;
+import static java.time.Duration.ofMillis;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertNull;
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertTimeout;
 
 /**
  * Date: 12/19/15 - 11:58 AM
@@ -52,12 +54,14 @@ public abstract class AbstractHolderTest {
   /**
    * This test shows that the heavy field is not instantiated until the method getHeavy is called
    */
-  @Test(timeout = 3000)
+  @Test
   public void testGetHeavy() throws Exception {
-    assertNull(getInternalHeavyValue());
-    assertNotNull(getHeavy());
-    assertNotNull(getInternalHeavyValue());
-    assertSame(getHeavy(), getInternalHeavyValue());
+    assertTimeout(ofMillis(3000), () -> {
+      assertNull(getInternalHeavyValue());
+      assertNotNull(getHeavy());
+      assertNotNull(getInternalHeavyValue());
+      assertSame(getHeavy(), getInternalHeavyValue());
+    });
   }
 
 }

lazy-loading/src/test/java/com/iluwatar/lazy/loading/AppTest.java

@@ -22,7 +22,7 @@
  */
 package com.iluwatar.lazy.loading;
 
-import org.junit.Test;
+import org.junit.jupiter.api.Test;
 
 /**
  *