Prevent improper use of testing framework APIs

Prior to this commit, a lot of work had been done to prevent improper
use of testing Framework APIs throughout the codebase; however, there
were still some loopholes.

This commit addresses these loopholes by introducing additional
Checkstyle rules (and modifying existing rules) to prevent improper use
of testing framework APIs in production code as well as in test code.

- Checkstyle rules for banned imports have been refactored into
  multiple rules specific to JUnit 3, JUnit 4, JUnit Jupiter, and
  TestNG.
- Accidental usage of org.junit.Assume has been switched to
  org.junit.jupiter.api.Assumptions.
- All test classes now reside under org.springframework packages.
- All test classes (including abstract test classes) now conform to the
  `*Tests` naming convention.
  - As an added bonus, tests in the renamed
    ScenariosForSpringSecurityExpressionTests are now included in the
    build.
- Dead JUnit 4 parameterized code has been removed from
  DefaultServerWebExchangeCheckNotModifiedTests.

Closes gh-22962

integration-tests/src/test/java/org/springframework/beans/factory/xml/Component.java

@@ -0,0 +1,44 @@
+/*
+ * Copyright 2002-2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.beans.factory.xml;
+
+import java.util.ArrayList;
+import java.util.List;
+
+public class Component {
+
+	private String name;
+	private List<Component> components = new ArrayList<>();
+
+	// mmm, there is no setter method for the 'components'
+	public void addComponent(Component component) {
+		this.components.add(component);
+	}
+
+	public List<Component> getComponents() {
+		return components;
+	}
+
+	public String getName() {
+		return name;
+	}
+
+	public void setName(String name) {
+		this.name = name;
+	}
+
+}

integration-tests/src/test/java/org/springframework/beans/factory/xml/ComponentBeanDefinitionParser.java

@@ -0,0 +1,63 @@
+/*
+ * Copyright 2002-2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.beans.factory.xml;
+
+import java.util.List;
+
+import org.w3c.dom.Element;
+
+import org.springframework.beans.factory.config.BeanDefinition;
+import org.springframework.beans.factory.support.AbstractBeanDefinition;
+import org.springframework.beans.factory.support.BeanDefinitionBuilder;
+import org.springframework.beans.factory.support.ManagedList;
+import org.springframework.util.CollectionUtils;
+import org.springframework.util.xml.DomUtils;
+
+public class ComponentBeanDefinitionParser extends AbstractBeanDefinitionParser {
+
+	@Override
+	protected AbstractBeanDefinition parseInternal(Element element, ParserContext parserContext) {
+		return parseComponentElement(element);
+	}
+
+	private static AbstractBeanDefinition parseComponentElement(Element element) {
+		BeanDefinitionBuilder factory = BeanDefinitionBuilder.rootBeanDefinition(ComponentFactoryBean.class);
+		factory.addPropertyValue("parent", parseComponent(element));
+
+		List<Element> childElements = DomUtils.getChildElementsByTagName(element, "component");
+		if (!CollectionUtils.isEmpty(childElements)) {
+			parseChildComponents(childElements, factory);
+		}
+
+		return factory.getBeanDefinition();
+	}
+
+	private static BeanDefinition parseComponent(Element element) {
+		BeanDefinitionBuilder component = BeanDefinitionBuilder.rootBeanDefinition(Component.class);
+		component.addPropertyValue("name", element.getAttribute("name"));
+		return component.getBeanDefinition();
+	}
+
+	private static void parseChildComponents(List<Element> childElements, BeanDefinitionBuilder factory) {
+		ManagedList<BeanDefinition> children = new ManagedList<>(childElements.size());
+		for (Element element : childElements) {
+			children.add(parseComponentElement(element));
+		}
+		factory.addPropertyValue("children", children);
+	}
+
+}

integration-tests/src/test/java/org/springframework/beans/factory/xml/ComponentBeanDefinitionParserTests.java

@@ -0,0 +1,81 @@
+/*
+ * Copyright 2002-2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.beans.factory.xml;
+
+import java.util.List;
+
+import org.junit.jupiter.api.AfterAll;
+import org.junit.jupiter.api.BeforeAll;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.TestInstance;
+import org.junit.jupiter.api.TestInstance.Lifecycle;
+
+import org.springframework.beans.factory.support.DefaultListableBeanFactory;
+import org.springframework.core.io.ClassPathResource;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * @author Costin Leau
+ */
+@TestInstance(Lifecycle.PER_CLASS)
+class ComponentBeanDefinitionParserTests {
+
+	private final DefaultListableBeanFactory bf = new DefaultListableBeanFactory();
+
+
+	@BeforeAll
+	void setUp() throws Exception {
+		new XmlBeanDefinitionReader(bf).loadBeanDefinitions(
+			new ClassPathResource("component-config.xml", ComponentBeanDefinitionParserTests.class));
+	}
+
+	@AfterAll
+	void tearDown() {
+		bf.destroySingletons();
+	}
+
+	@Test
+	void testBionicBasic() {
+		Component cp = getBionicFamily();
+		assertThat("Bionic-1").isEqualTo(cp.getName());
+	}
+
+	@Test
+	void testBionicFirstLevelChildren() {
+		Component cp = getBionicFamily();
+		List<Component> components = cp.getComponents();
+		assertThat(2).isEqualTo(components.size());
+		assertThat("Mother-1").isEqualTo(components.get(0).getName());
+		assertThat("Rock-1").isEqualTo(components.get(1).getName());
+	}
+
+	@Test
+	void testBionicSecondLevelChildren() {
+		Component cp = getBionicFamily();
+		List<Component> components = cp.getComponents().get(0).getComponents();
+		assertThat(2).isEqualTo(components.size());
+		assertThat("Karate-1").isEqualTo(components.get(0).getName());
+		assertThat("Sport-1").isEqualTo(components.get(1).getName());
+	}
+
+	private Component getBionicFamily() {
+		return bf.getBean("bionic-family", Component.class);
+	}
+
+}
+

integration-tests/src/test/java/org/springframework/beans/factory/xml/ComponentFactoryBean.java

@@ -0,0 +1,56 @@
+/*
+ * Copyright 2002-2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.beans.factory.xml;
+
+import java.util.List;
+
+import org.springframework.beans.factory.FactoryBean;
+
+public class ComponentFactoryBean implements FactoryBean<Component> {
+
+	private Component parent;
+	private List<Component> children;
+
+	public void setParent(Component parent) {
+		this.parent = parent;
+	}
+
+	public void setChildren(List<Component> children) {
+		this.children = children;
+	}
+
+	@Override
+	public Component getObject() throws Exception {
+		if (this.children != null && this.children.size() > 0) {
+			for (Component child : children) {
+				this.parent.addComponent(child);
+			}
+		}
+		return this.parent;
+	}
+
+	@Override
+	public Class<Component> getObjectType() {
+		return Component.class;
+	}
+
+	@Override
+	public boolean isSingleton() {
+		return true;
+	}
+
+}

integration-tests/src/test/java/org/springframework/beans/factory/xml/ComponentNamespaceHandler.java

@@ -0,0 +1,25 @@
+/*
+ * Copyright 2002-2019 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.springframework.beans.factory.xml;
+
+public class ComponentNamespaceHandler extends NamespaceHandlerSupport {
+
+	@Override
+	public void init() {
+		registerBeanDefinitionParser("component", new ComponentBeanDefinitionParser());
+	}
+}