BAEL-1039: Introduction to Derive4J (#5845)

libraries/src/test/java/com/baeldung/derive4j/adt/EitherUnitTest.java

@@ -0,0 +1,33 @@
+package com.baeldung.derive4j.adt;
+
+import org.assertj.core.api.Assertions;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.mockito.Mockito;
+import org.mockito.junit.MockitoJUnitRunner;
+
+import java.util.Optional;
+import java.util.function.Function;
+@RunWith(MockitoJUnitRunner.class)
+public class EitherUnitTest {
+    @Test
+    public void testEitherIsCreatedFromRight() {
+       Either<Exception, String> either = Eithers.right("Okay");
+       Optional<Exception> leftOptional = Eithers.getLeft(either);
+       Optional<String> rightOptional = Eithers.getRight(either);
+       Assertions.assertThat(leftOptional).isEmpty();
+       Assertions.assertThat(rightOptional).hasValue("Okay");
+
+    }
+
+    @Test
+    public void testEitherIsMatchedWithRight() {
+        Either<Exception, String> either = Eithers.right("Okay");
+        Function<Exception, String> leftFunction = Mockito.mock(Function.class);
+        Function<String, String> rightFunction = Mockito.mock(Function.class);
+        either.match(leftFunction, rightFunction);
+        Mockito.verify(rightFunction, Mockito.times(1)).apply("Okay");
+        Mockito.verify(leftFunction, Mockito.times(0)).apply(Mockito.any(Exception.class));
+    }
+
+}

libraries/src/test/java/com/baeldung/derive4j/lazy/LazyRequestUnitTest.java

@@ -0,0 +1,28 @@
+package com.baeldung.derive4j.lazy;
+
+import org.junit.Assert;
+import org.junit.Test;
+import org.mockito.Mockito;
+
+import java.util.function.Supplier;
+
+public class LazyRequestUnitTest {
+
+    @Test
+    public void givenLazyContstructedRequest_whenRequestIsReferenced_thenRequestIsLazilyContructed() {
+        LazyRequestSupplier mockSupplier = Mockito.spy(new LazyRequestSupplier());
+
+        LazyRequest request = LazyRequestImpl.lazy(() -> mockSupplier.get());
+        Mockito.verify(mockSupplier, Mockito.times(0)).get();
+        Assert.assertEquals(LazyRequestImpl.getPath(request), "http://test.com/get");
+        Mockito.verify(mockSupplier, Mockito.times(1)).get();
+
+    }
+
+    class LazyRequestSupplier implements Supplier<LazyRequest> {
+        @Override
+        public LazyRequest get() {
+            return LazyRequestImpl.GET("http://test.com/get");
+        }
+    }
+}

libraries/src/test/java/com/baeldung/derive4j/pattern/HTTPRequestUnitTest.java

@@ -0,0 +1,22 @@
+package com.baeldung.derive4j.pattern;
+
+import org.junit.Assert;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+public class HTTPRequestUnitTest {
+    public static HTTPServer server;
+
+    @BeforeClass
+    public static void setUp() {
+        server = new HTTPServer();
+    }
+
+    @Test
+    public void givenHttpGETRequest_whenRequestReachesServer_thenProperResponseIsReturned() {
+        HTTPRequest postRequest = HTTPRequests.POST("http://test.com/post", "Resource");
+        HTTPResponse response = server.acceptRequest(postRequest);
+        Assert.assertEquals(201, response.getStatusCode());
+        Assert.assertEquals(HTTPServer.POST_RESPONSE_BODY, response.getResponseBody());
+    }
+}