maven-plugin-testing-harness/src/main/java/org/apache/maven/api/plugin/testing/MojoExtension.java - maven-plugin-testing - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF licenses this file
  * to you 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
  *
  *   http://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.apache.maven.api.plugin.testing;

 import java.io.BufferedReader;
 import java.io.File;
 import java.io.InputStream;
 import java.io.Reader;
 import java.io.StringReader;
 import java.lang.reflect.AccessibleObject;
 import java.lang.reflect.Field;
 import java.net.URL;
 import java.nio.file.Path;
 import java.nio.file.Paths;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
 import java.util.Objects;
 import java.util.Optional;
 import java.util.Set;
 import java.util.stream.Collectors;
 import java.util.stream.Stream;

 import com.google.inject.internal.ProviderMethodsModule;
 import org.apache.maven.api.MojoExecution;
 import org.apache.maven.api.Project;
 import org.apache.maven.api.Session;
 import org.apache.maven.api.plugin.Log;
 import org.apache.maven.api.plugin.Mojo;
 import org.apache.maven.api.xml.XmlNode;
 import org.apache.maven.configuration.internal.EnhancedComponentConfigurator;
 import org.apache.maven.internal.impl.DefaultLog;
 import org.apache.maven.internal.xml.XmlNodeImpl;
 import org.apache.maven.lifecycle.internal.MojoDescriptorCreator;
 import org.apache.maven.plugin.PluginParameterExpressionEvaluatorV4;
 import org.apache.maven.plugin.descriptor.MojoDescriptor;
 import org.apache.maven.plugin.descriptor.Parameter;
 import org.apache.maven.plugin.descriptor.PluginDescriptor;
 import org.apache.maven.plugin.descriptor.PluginDescriptorBuilder;
 import org.codehaus.plexus.DefaultPlexusContainer;
 import org.codehaus.plexus.PlexusContainer;
 import org.codehaus.plexus.component.configurator.ComponentConfigurator;
 import org.codehaus.plexus.component.configurator.expression.ExpressionEvaluationException;
 import org.codehaus.plexus.component.configurator.expression.ExpressionEvaluator;
 import org.codehaus.plexus.component.configurator.expression.TypeAwareExpressionEvaluator;
 import org.codehaus.plexus.component.repository.ComponentDescriptor;
 import org.codehaus.plexus.component.repository.exception.ComponentLookupException;
 import org.codehaus.plexus.configuration.xml.XmlPlexusConfiguration;
 import org.codehaus.plexus.testing.PlexusExtension;
 import org.codehaus.plexus.util.InterpolationFilterReader;
 import org.codehaus.plexus.util.ReaderFactory;
 import org.codehaus.plexus.util.ReflectionUtils;
 import org.codehaus.plexus.util.xml.XmlStreamReader;
 import org.codehaus.plexus.util.xml.Xpp3Dom;
 import org.codehaus.plexus.util.xml.Xpp3DomBuilder;
 import org.junit.jupiter.api.extension.ExtensionContext;
 import org.junit.jupiter.api.extension.ParameterContext;
 import org.junit.jupiter.api.extension.ParameterResolutionException;
 import org.junit.jupiter.api.extension.ParameterResolver;
 import org.slf4j.LoggerFactory;

 /**
  * JUnit extension to help testing Mojos. The extension should be automatically registered
  * by adding the {@link MojoTest} annotation on the test class.
  *
  * @see MojoTest
  * @see InjectMojo
  * @see MojoParameter
  */
 public class MojoExtension extends PlexusExtension implements ParameterResolver {

     @Override
     public boolean supportsParameter(ParameterContext parameterContext, ExtensionContext extensionContext)
             throws ParameterResolutionException {
         return parameterContext.isAnnotated(InjectMojo.class)
                 || parameterContext.getDeclaringExecutable().isAnnotationPresent(InjectMojo.class);
     }

     @Override
     public Object resolveParameter(ParameterContext parameterContext, ExtensionContext extensionContext)
             throws ParameterResolutionException {
         try {
             InjectMojo injectMojo = parameterContext
                     .findAnnotation(InjectMojo.class)
                     .orElseGet(() -> parameterContext.getDeclaringExecutable().getAnnotation(InjectMojo.class));

             Set<MojoParameter> mojoParameters =
                     new HashSet<>(parameterContext.findRepeatableAnnotations(MojoParameter.class));

             Optional.ofNullable(parameterContext.getDeclaringExecutable().getAnnotation(MojoParameter.class))
                     .ifPresent(mojoParameters::add);

             Optional.ofNullable(parameterContext.getDeclaringExecutable().getAnnotation(MojoParameters.class))
                     .map(MojoParameters::value)
                     .map(Arrays::asList)
                     .ifPresent(mojoParameters::addAll);

             Class<?> holder = parameterContext.getTarget().get().getClass();
             PluginDescriptor descriptor = extensionContext
                     .getStore(ExtensionContext.Namespace.GLOBAL)
                     .get(PluginDescriptor.class, PluginDescriptor.class);
             return lookupMojo(holder, injectMojo, mojoParameters, descriptor);
         } catch (Exception e) {
             throw new ParameterResolutionException("Unable to resolve parameter", e);
         }
     }

     @Override
     public void beforeEach(ExtensionContext context) throws Exception {
         // TODO provide protected setters in PlexusExtension
         Field field = PlexusExtension.class.getDeclaredField("basedir");
         field.setAccessible(true);
         field.set(null, getBasedir());
         field = PlexusExtension.class.getDeclaredField("context");
         field.setAccessible(true);
         field.set(this, context);

         getContainer().addComponent(getContainer(), PlexusContainer.class.getName());

         ((DefaultPlexusContainer) getContainer()).addPlexusInjector(Collections.emptyList(), binder -> {
             binder.install(ProviderMethodsModule.forObject(context.getRequiredTestInstance()));
             binder.requestInjection(context.getRequiredTestInstance());
             binder.bind(Log.class).toInstance(new DefaultLog(LoggerFactory.getLogger("anonymous")));
         });

         Map<Object, Object> map = getContainer().getContext().getContextData();

         ClassLoader classLoader = context.getRequiredTestClass().getClassLoader();
         try (InputStream is = Objects.requireNonNull(
                         classLoader.getResourceAsStream(getPluginDescriptorLocation()),
                         "Unable to find plugin descriptor: " + getPluginDescriptorLocation());
                 Reader reader = new BufferedReader(new XmlStreamReader(is));
                 InterpolationFilterReader interpolationReader = new InterpolationFilterReader(reader, map, "${", "}")) {

             PluginDescriptor pluginDescriptor = new PluginDescriptorBuilder().build(interpolationReader);

             context.getStore(ExtensionContext.Namespace.GLOBAL).put(PluginDescriptor.class, pluginDescriptor);

             for (ComponentDescriptor<?> desc : pluginDescriptor.getComponents()) {
                 getContainer().addComponentDescriptor(desc);
             }
         }
     }

     protected String getPluginDescriptorLocation() {
         return "META-INF/maven/plugin.xml";
     }

     private Mojo lookupMojo(
             Class<?> holder,
             InjectMojo injectMojo,
             Collection<MojoParameter> mojoParameters,
             PluginDescriptor descriptor)
             throws Exception {
         String goal = injectMojo.goal();
         String pom = injectMojo.pom();
         String[] coord = mojoCoordinates(goal);
         Xpp3Dom pomDom;
         if (pom.startsWith("file:")) {
             Path path = Paths.get(getBasedir()).resolve(pom.substring("file:".length()));
             pomDom = Xpp3DomBuilder.build(ReaderFactory.newXmlReader(path.toFile()));
         } else if (pom.startsWith("classpath:")) {
             URL url = holder.getResource(pom.substring("classpath:".length()));
             if (url == null) {
                 throw new IllegalStateException("Unable to find pom on classpath: " + pom);
             }
             pomDom = Xpp3DomBuilder.build(ReaderFactory.newXmlReader(url.openStream()));
         } else if (pom.contains("<project>")) {
             pomDom = Xpp3DomBuilder.build(new StringReader(pom));
         } else {
             Path path = Paths.get(getBasedir()).resolve(pom);
             pomDom = Xpp3DomBuilder.build(ReaderFactory.newXmlReader(path.toFile()));
         }
         XmlNode pluginConfiguration = extractPluginConfiguration(coord[1], pomDom);
         if (!mojoParameters.isEmpty()) {
             List<XmlNode> children = mojoParameters.stream()
                     .map(mp -> new XmlNodeImpl(mp.name(), mp.value()))
                     .collect(Collectors.toList());
             XmlNode config = new XmlNodeImpl("configuration", null, null, children, null);
             pluginConfiguration = XmlNode.merge(config, pluginConfiguration);
         }
         Mojo mojo = lookupMojo(coord, pluginConfiguration, descriptor);
         return mojo;
     }

     protected String[] mojoCoordinates(String goal) throws Exception {
         if (goal.matches(".*:.*:.*:.*")) {
             return goal.split(":");
         } else {
             Path pluginPom = Paths.get(getBasedir(), "pom.xml");
             Xpp3Dom pluginPomDom = Xpp3DomBuilder.build(ReaderFactory.newXmlReader(pluginPom.toFile()));
             String artifactId = pluginPomDom.getChild("artifactId").getValue();
             String groupId = resolveFromRootThenParent(pluginPomDom, "groupId");
             String version = resolveFromRootThenParent(pluginPomDom, "version");
             return new String[] {groupId, artifactId, version, goal};
         }
     }

     /**
      * lookup the mojo while we have all the relevent information
      */
     protected Mojo lookupMojo(String[] coord, XmlNode pluginConfiguration, PluginDescriptor descriptor)
             throws Exception {
         // pluginkey = groupId : artifactId : version : goal
         Mojo mojo = lookup(Mojo.class, coord[0] + ":" + coord[1] + ":" + coord[2] + ":" + coord[3]);
         for (MojoDescriptor mojoDescriptor : descriptor.getMojos()) {
             if (Objects.equals(
                     mojoDescriptor.getImplementation(), mojo.getClass().getName())) {
                 if (pluginConfiguration != null) {
                     pluginConfiguration = finalizeConfig(pluginConfiguration, mojoDescriptor);
                 }
             }
         }
         if (pluginConfiguration != null) {
             Session session = getContainer().lookup(Session.class);
             Project project;
             try {
                 project = getContainer().lookup(Project.class);
             } catch (ComponentLookupException e) {
                 project = null;
             }
             org.apache.maven.plugin.MojoExecution mojoExecution;
             try {
                 MojoExecution me = getContainer().lookup(MojoExecution.class);
                 mojoExecution = new org.apache.maven.plugin.MojoExecution(
                         new org.apache.maven.model.Plugin(me.getPlugin()), me.getGoal(), me.getExecutionId());
             } catch (ComponentLookupException e) {
                 mojoExecution = null;
             }
             ExpressionEvaluator evaluator = new WrapEvaluator(
                     getContainer(), new PluginParameterExpressionEvaluatorV4(session, project, mojoExecution));
             ComponentConfigurator configurator = new EnhancedComponentConfigurator();
             configurator.configureComponent(
                     mojo,
                     new XmlPlexusConfiguration(new Xpp3Dom(pluginConfiguration)),
                     evaluator,
                     getContainer().getContainerRealm());
         }

         return mojo;
     }

     private XmlNode finalizeConfig(XmlNode config, MojoDescriptor mojoDescriptor) {
         List<XmlNode> children = new ArrayList<>();
         if (mojoDescriptor != null && mojoDescriptor.getParameters() != null) {
             XmlNode defaultConfiguration =
                     MojoDescriptorCreator.convert(mojoDescriptor).getDom();
             for (Parameter parameter : mojoDescriptor.getParameters()) {
                 XmlNode parameterConfiguration = config.getChild(parameter.getName());
                 if (parameterConfiguration == null) {
                     parameterConfiguration = config.getChild(parameter.getAlias());
                 }
                 XmlNode parameterDefaults = defaultConfiguration.getChild(parameter.getName());
                 parameterConfiguration = XmlNode.merge(parameterConfiguration, parameterDefaults, Boolean.TRUE);
                 if (parameterConfiguration != null) {
                     Map<String, String> attributes = new HashMap<>(parameterConfiguration.getAttributes());
                     if (isEmpty(parameterConfiguration.getAttribute("implementation"))
                             && !isEmpty(parameter.getImplementation())) {
                         attributes.put("implementation", parameter.getImplementation());
                     }
                     parameterConfiguration = new XmlNodeImpl(
                             parameter.getName(),
                             parameterConfiguration.getValue(),
                             attributes,
                             parameterConfiguration.getChildren(),
                             parameterConfiguration.getInputLocation());

                     children.add(parameterConfiguration);
                 }
             }
         }
         return new XmlNodeImpl("configuration", null, null, children, null);
     }

     private boolean isEmpty(String str) {
         return str == null || str.isEmpty();
     }

     private static Optional<Xpp3Dom> child(Xpp3Dom element, String name) {
         return Optional.ofNullable(element.getChild(name));
     }

     private static Stream<Xpp3Dom> children(Xpp3Dom element) {
         return Stream.of(element.getChildren());
     }

     public static XmlNode extractPluginConfiguration(String artifactId, Xpp3Dom pomDom) throws Exception {
         Xpp3Dom pluginConfigurationElement = child(pomDom, "build")
                 .flatMap(buildElement -> child(buildElement, "plugins"))
                 .map(MojoExtension::children)
                 .orElseGet(Stream::empty)
                 .filter(e -> e.getChild("artifactId").getValue().equals(artifactId))
                 .findFirst()
                 .flatMap(buildElement -> child(buildElement, "configuration"))
                 .orElseThrow(
                         () -> new ConfigurationException("Cannot find a configuration element for a plugin with an "
                                 + "artifactId of " + artifactId + "."));
         return pluginConfigurationElement.getDom();
     }

     /**
      * sometimes the parent element might contain the correct value so generalize that access
      *
      * TODO find out where this is probably done elsewhere
      */
     private static String resolveFromRootThenParent(Xpp3Dom pluginPomDom, String element) throws Exception {
         return Optional.ofNullable(child(pluginPomDom, element).orElseGet(() -> child(pluginPomDom, "parent")
                         .flatMap(e -> child(e, element))
                         .orElse(null)))
                 .map(Xpp3Dom::getValue)
                 .orElseThrow(() -> new Exception("unable to determine " + element));
     }

     /**
      * Convenience method to obtain the value of a variable on a mojo that might not have a getter.
      * <br>
      * NOTE: the caller is responsible for casting to what the desired type is.
      */
     public static Object getVariableValueFromObject(Object object, String variable) throws IllegalAccessException {
         Field field = ReflectionUtils.getFieldByNameIncludingSuperclasses(variable, object.getClass());
         field.setAccessible(true);
         return field.get(object);
     }

     /**
      * Convenience method to obtain all variables and values from the mojo (including its superclasses)
      * <br>
      * Note: the values in the map are of type Object so the caller is responsible for casting to desired types.
      */
     public static Map<String, Object> getVariablesAndValuesFromObject(Object object) throws IllegalAccessException {
         return getVariablesAndValuesFromObject(object.getClass(), object);
     }

     /**
      * Convenience method to obtain all variables and values from the mojo (including its superclasses)
      * <br>
      * Note: the values in the map are of type Object so the caller is responsible for casting to desired types.
      *
      * @return map of variable names and values
      */
     public static Map<String, Object> getVariablesAndValuesFromObject(Class<?> clazz, Object object)
             throws IllegalAccessException {
         Map<String, Object> map = new HashMap<>();
         Field[] fields = clazz.getDeclaredFields();
         AccessibleObject.setAccessible(fields, true);
         for (Field field : fields) {
             map.put(field.getName(), field.get(object));
         }
         Class<?> superclass = clazz.getSuperclass();
         if (!Object.class.equals(superclass)) {
             map.putAll(getVariablesAndValuesFromObject(superclass, object));
         }
         return map;
     }

     /**
      * Convenience method to set values to variables in objects that don't have setters
      */
     public static void setVariableValueToObject(Object object, String variable, Object value)
             throws IllegalAccessException {
         Field field = ReflectionUtils.getFieldByNameIncludingSuperclasses(variable, object.getClass());
         Objects.requireNonNull(field, "Field " + variable + " not found");
         field.setAccessible(true);
         field.set(object, value);
     }

     static class WrapEvaluator implements TypeAwareExpressionEvaluator {

         private final PlexusContainer container;
         private final TypeAwareExpressionEvaluator evaluator;

         WrapEvaluator(PlexusContainer container, TypeAwareExpressionEvaluator evaluator) {
             this.container = container;
             this.evaluator = evaluator;
         }

         @Override
         public Object evaluate(String expression) throws ExpressionEvaluationException {
             return evaluate(expression, null);
         }

         @Override
         public Object evaluate(String expression, Class<?> type) throws ExpressionEvaluationException {
             Object value = evaluator.evaluate(expression, type);
             if (value == null) {
                 String expr = stripTokens(expression);
                 if (expr != null) {
                     try {
                         value = container.lookup(type, expr);
                     } catch (ComponentLookupException e) {
                         // nothing
                     }
                 }
             }
             return value;
         }

         private String stripTokens(String expr) {
             if (expr.startsWith("${") && expr.endsWith("}")) {
                 return expr.substring(2, expr.length() - 1);
             }
             return null;
         }

         @Override
         public File alignToBaseDirectory(File path) {
             return evaluator.alignToBaseDirectory(path);
         }
     }
 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF licenses this file
	* to you 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
	*
	* http://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.apache.maven.api.plugin.testing;

	import java.io.BufferedReader;
	import java.io.File;
	import java.io.InputStream;
	import java.io.Reader;
	import java.io.StringReader;
	import java.lang.reflect.AccessibleObject;
	import java.lang.reflect.Field;
	import java.net.URL;
	import java.nio.file.Path;
	import java.nio.file.Paths;
	import java.util.ArrayList;
	import java.util.Arrays;
	import java.util.Collection;
	import java.util.Collections;
	import java.util.HashMap;
	import java.util.HashSet;
	import java.util.List;
	import java.util.Map;
	import java.util.Objects;
	import java.util.Optional;
	import java.util.Set;
	import java.util.stream.Collectors;
	import java.util.stream.Stream;

	import com.google.inject.internal.ProviderMethodsModule;
	import org.apache.maven.api.MojoExecution;
	import org.apache.maven.api.Project;
	import org.apache.maven.api.Session;
	import org.apache.maven.api.plugin.Log;
	import org.apache.maven.api.plugin.Mojo;
	import org.apache.maven.api.xml.XmlNode;
	import org.apache.maven.configuration.internal.EnhancedComponentConfigurator;
	import org.apache.maven.internal.impl.DefaultLog;
	import org.apache.maven.internal.xml.XmlNodeImpl;
	import org.apache.maven.lifecycle.internal.MojoDescriptorCreator;
	import org.apache.maven.plugin.PluginParameterExpressionEvaluatorV4;
	import org.apache.maven.plugin.descriptor.MojoDescriptor;
	import org.apache.maven.plugin.descriptor.Parameter;
	import org.apache.maven.plugin.descriptor.PluginDescriptor;
	import org.apache.maven.plugin.descriptor.PluginDescriptorBuilder;
	import org.codehaus.plexus.DefaultPlexusContainer;
	import org.codehaus.plexus.PlexusContainer;
	import org.codehaus.plexus.component.configurator.ComponentConfigurator;
	import org.codehaus.plexus.component.configurator.expression.ExpressionEvaluationException;
	import org.codehaus.plexus.component.configurator.expression.ExpressionEvaluator;
	import org.codehaus.plexus.component.configurator.expression.TypeAwareExpressionEvaluator;
	import org.codehaus.plexus.component.repository.ComponentDescriptor;
	import org.codehaus.plexus.component.repository.exception.ComponentLookupException;
	import org.codehaus.plexus.configuration.xml.XmlPlexusConfiguration;
	import org.codehaus.plexus.testing.PlexusExtension;
	import org.codehaus.plexus.util.InterpolationFilterReader;
	import org.codehaus.plexus.util.ReaderFactory;
	import org.codehaus.plexus.util.ReflectionUtils;
	import org.codehaus.plexus.util.xml.XmlStreamReader;
	import org.codehaus.plexus.util.xml.Xpp3Dom;
	import org.codehaus.plexus.util.xml.Xpp3DomBuilder;
	import org.junit.jupiter.api.extension.ExtensionContext;
	import org.junit.jupiter.api.extension.ParameterContext;
	import org.junit.jupiter.api.extension.ParameterResolutionException;
	import org.junit.jupiter.api.extension.ParameterResolver;
	import org.slf4j.LoggerFactory;

	/**
	* JUnit extension to help testing Mojos. The extension should be automatically registered
	* by adding the {@link MojoTest} annotation on the test class.
	*
	* @see MojoTest
	* @see InjectMojo
	* @see MojoParameter
	*/
	public class MojoExtension extends PlexusExtension implements ParameterResolver {

	@Override
	public boolean supportsParameter(ParameterContext parameterContext, ExtensionContext extensionContext)
	throws ParameterResolutionException {
	return parameterContext.isAnnotated(InjectMojo.class)
	\|\| parameterContext.getDeclaringExecutable().isAnnotationPresent(InjectMojo.class);
	}

	@Override
	public Object resolveParameter(ParameterContext parameterContext, ExtensionContext extensionContext)
	throws ParameterResolutionException {
	try {
	InjectMojo injectMojo = parameterContext
	.findAnnotation(InjectMojo.class)
	.orElseGet(() -> parameterContext.getDeclaringExecutable().getAnnotation(InjectMojo.class));

	Set<MojoParameter> mojoParameters =
	new HashSet<>(parameterContext.findRepeatableAnnotations(MojoParameter.class));

	Optional.ofNullable(parameterContext.getDeclaringExecutable().getAnnotation(MojoParameter.class))
	.ifPresent(mojoParameters::add);

	Optional.ofNullable(parameterContext.getDeclaringExecutable().getAnnotation(MojoParameters.class))
	.map(MojoParameters::value)
	.map(Arrays::asList)
	.ifPresent(mojoParameters::addAll);

	Class<?> holder = parameterContext.getTarget().get().getClass();
	PluginDescriptor descriptor = extensionContext
	.getStore(ExtensionContext.Namespace.GLOBAL)
	.get(PluginDescriptor.class, PluginDescriptor.class);
	return lookupMojo(holder, injectMojo, mojoParameters, descriptor);
	} catch (Exception e) {
	throw new ParameterResolutionException("Unable to resolve parameter", e);
	}
	}

	@Override
	public void beforeEach(ExtensionContext context) throws Exception {
	// TODO provide protected setters in PlexusExtension
	Field field = PlexusExtension.class.getDeclaredField("basedir");
	field.setAccessible(true);
	field.set(null, getBasedir());
	field = PlexusExtension.class.getDeclaredField("context");
	field.setAccessible(true);
	field.set(this, context);

	getContainer().addComponent(getContainer(), PlexusContainer.class.getName());

	((DefaultPlexusContainer) getContainer()).addPlexusInjector(Collections.emptyList(), binder -> {
	binder.install(ProviderMethodsModule.forObject(context.getRequiredTestInstance()));
	binder.requestInjection(context.getRequiredTestInstance());
	binder.bind(Log.class).toInstance(new DefaultLog(LoggerFactory.getLogger("anonymous")));
	});

	Map<Object, Object> map = getContainer().getContext().getContextData();

	ClassLoader classLoader = context.getRequiredTestClass().getClassLoader();
	try (InputStream is = Objects.requireNonNull(
	classLoader.getResourceAsStream(getPluginDescriptorLocation()),
	"Unable to find plugin descriptor: " + getPluginDescriptorLocation());
	Reader reader = new BufferedReader(new XmlStreamReader(is));
	InterpolationFilterReader interpolationReader = new InterpolationFilterReader(reader, map, "${", "}")) {

	PluginDescriptor pluginDescriptor = new PluginDescriptorBuilder().build(interpolationReader);

	context.getStore(ExtensionContext.Namespace.GLOBAL).put(PluginDescriptor.class, pluginDescriptor);

	for (ComponentDescriptor<?> desc : pluginDescriptor.getComponents()) {
	getContainer().addComponentDescriptor(desc);
	}
	}
	}

	protected String getPluginDescriptorLocation() {
	return "META-INF/maven/plugin.xml";
	}

	private Mojo lookupMojo(
	Class<?> holder,
	InjectMojo injectMojo,
	Collection<MojoParameter> mojoParameters,
	PluginDescriptor descriptor)
	throws Exception {
	String goal = injectMojo.goal();
	String pom = injectMojo.pom();
	String[] coord = mojoCoordinates(goal);
	Xpp3Dom pomDom;
	if (pom.startsWith("file:")) {
	Path path = Paths.get(getBasedir()).resolve(pom.substring("file:".length()));
	pomDom = Xpp3DomBuilder.build(ReaderFactory.newXmlReader(path.toFile()));
	} else if (pom.startsWith("classpath:")) {
	URL url = holder.getResource(pom.substring("classpath:".length()));
	if (url == null) {
	throw new IllegalStateException("Unable to find pom on classpath: " + pom);
	}
	pomDom = Xpp3DomBuilder.build(ReaderFactory.newXmlReader(url.openStream()));
	} else if (pom.contains("<project>")) {
	pomDom = Xpp3DomBuilder.build(new StringReader(pom));
	} else {
	Path path = Paths.get(getBasedir()).resolve(pom);
	pomDom = Xpp3DomBuilder.build(ReaderFactory.newXmlReader(path.toFile()));
	}
	XmlNode pluginConfiguration = extractPluginConfiguration(coord[1], pomDom);
	if (!mojoParameters.isEmpty()) {
	List<XmlNode> children = mojoParameters.stream()
	.map(mp -> new XmlNodeImpl(mp.name(), mp.value()))
	.collect(Collectors.toList());
	XmlNode config = new XmlNodeImpl("configuration", null, null, children, null);
	pluginConfiguration = XmlNode.merge(config, pluginConfiguration);
	}
	Mojo mojo = lookupMojo(coord, pluginConfiguration, descriptor);
	return mojo;
	}

	protected String[] mojoCoordinates(String goal) throws Exception {
	if (goal.matches(".:.:.:.")) {
	return goal.split(":");
	} else {
	Path pluginPom = Paths.get(getBasedir(), "pom.xml");
	Xpp3Dom pluginPomDom = Xpp3DomBuilder.build(ReaderFactory.newXmlReader(pluginPom.toFile()));
	String artifactId = pluginPomDom.getChild("artifactId").getValue();
	String groupId = resolveFromRootThenParent(pluginPomDom, "groupId");
	String version = resolveFromRootThenParent(pluginPomDom, "version");
	return new String[] {groupId, artifactId, version, goal};
	}
	}

	/**
	* lookup the mojo while we have all the relevent information
	*/
	protected Mojo lookupMojo(String[] coord, XmlNode pluginConfiguration, PluginDescriptor descriptor)
	throws Exception {
	// pluginkey = groupId : artifactId : version : goal
	Mojo mojo = lookup(Mojo.class, coord[0] + ":" + coord[1] + ":" + coord[2] + ":" + coord[3]);
	for (MojoDescriptor mojoDescriptor : descriptor.getMojos()) {
	if (Objects.equals(
	mojoDescriptor.getImplementation(), mojo.getClass().getName())) {
	if (pluginConfiguration != null) {
	pluginConfiguration = finalizeConfig(pluginConfiguration, mojoDescriptor);
	}
	}
	}
	if (pluginConfiguration != null) {
	Session session = getContainer().lookup(Session.class);
	Project project;
	try {
	project = getContainer().lookup(Project.class);
	} catch (ComponentLookupException e) {
	project = null;
	}
	org.apache.maven.plugin.MojoExecution mojoExecution;
	try {
	MojoExecution me = getContainer().lookup(MojoExecution.class);
	mojoExecution = new org.apache.maven.plugin.MojoExecution(
	new org.apache.maven.model.Plugin(me.getPlugin()), me.getGoal(), me.getExecutionId());
	} catch (ComponentLookupException e) {
	mojoExecution = null;
	}
	ExpressionEvaluator evaluator = new WrapEvaluator(
	getContainer(), new PluginParameterExpressionEvaluatorV4(session, project, mojoExecution));
	ComponentConfigurator configurator = new EnhancedComponentConfigurator();
	configurator.configureComponent(
	mojo,
	new XmlPlexusConfiguration(new Xpp3Dom(pluginConfiguration)),
	evaluator,
	getContainer().getContainerRealm());
	}

	return mojo;
	}

	private XmlNode finalizeConfig(XmlNode config, MojoDescriptor mojoDescriptor) {
	List<XmlNode> children = new ArrayList<>();
	if (mojoDescriptor != null && mojoDescriptor.getParameters() != null) {
	XmlNode defaultConfiguration =
	MojoDescriptorCreator.convert(mojoDescriptor).getDom();
	for (Parameter parameter : mojoDescriptor.getParameters()) {
	XmlNode parameterConfiguration = config.getChild(parameter.getName());
	if (parameterConfiguration == null) {
	parameterConfiguration = config.getChild(parameter.getAlias());
	}
	XmlNode parameterDefaults = defaultConfiguration.getChild(parameter.getName());
	parameterConfiguration = XmlNode.merge(parameterConfiguration, parameterDefaults, Boolean.TRUE);
	if (parameterConfiguration != null) {
	Map<String, String> attributes = new HashMap<>(parameterConfiguration.getAttributes());
	if (isEmpty(parameterConfiguration.getAttribute("implementation"))
	&& !isEmpty(parameter.getImplementation())) {
	attributes.put("implementation", parameter.getImplementation());
	}
	parameterConfiguration = new XmlNodeImpl(
	parameter.getName(),
	parameterConfiguration.getValue(),
	attributes,
	parameterConfiguration.getChildren(),
	parameterConfiguration.getInputLocation());

	children.add(parameterConfiguration);
	}
	}
	}
	return new XmlNodeImpl("configuration", null, null, children, null);
	}

	private boolean isEmpty(String str) {
	return str == null \|\| str.isEmpty();
	}

	private static Optional<Xpp3Dom> child(Xpp3Dom element, String name) {
	return Optional.ofNullable(element.getChild(name));
	}

	private static Stream<Xpp3Dom> children(Xpp3Dom element) {
	return Stream.of(element.getChildren());
	}

	public static XmlNode extractPluginConfiguration(String artifactId, Xpp3Dom pomDom) throws Exception {
	Xpp3Dom pluginConfigurationElement = child(pomDom, "build")
	.flatMap(buildElement -> child(buildElement, "plugins"))
	.map(MojoExtension::children)
	.orElseGet(Stream::empty)
	.filter(e -> e.getChild("artifactId").getValue().equals(artifactId))
	.findFirst()
	.flatMap(buildElement -> child(buildElement, "configuration"))
	.orElseThrow(
	() -> new ConfigurationException("Cannot find a configuration element for a plugin with an "
	+ "artifactId of " + artifactId + "."));
	return pluginConfigurationElement.getDom();
	}

	/**
	* sometimes the parent element might contain the correct value so generalize that access
	*
	* TODO find out where this is probably done elsewhere
	*/
	private static String resolveFromRootThenParent(Xpp3Dom pluginPomDom, String element) throws Exception {
	return Optional.ofNullable(child(pluginPomDom, element).orElseGet(() -> child(pluginPomDom, "parent")
	.flatMap(e -> child(e, element))
	.orElse(null)))
	.map(Xpp3Dom::getValue)
	.orElseThrow(() -> new Exception("unable to determine " + element));
	}

	/**
	* Convenience method to obtain the value of a variable on a mojo that might not have a getter.
	* <br>
	* NOTE: the caller is responsible for casting to what the desired type is.
	*/
	public static Object getVariableValueFromObject(Object object, String variable) throws IllegalAccessException {
	Field field = ReflectionUtils.getFieldByNameIncludingSuperclasses(variable, object.getClass());
	field.setAccessible(true);
	return field.get(object);
	}

	/**
	* Convenience method to obtain all variables and values from the mojo (including its superclasses)
	* <br>
	* Note: the values in the map are of type Object so the caller is responsible for casting to desired types.
	*/
	public static Map<String, Object> getVariablesAndValuesFromObject(Object object) throws IllegalAccessException {
	return getVariablesAndValuesFromObject(object.getClass(), object);
	}

	/**
	* Convenience method to obtain all variables and values from the mojo (including its superclasses)
	* <br>
	* Note: the values in the map are of type Object so the caller is responsible for casting to desired types.
	*
	* @return map of variable names and values
	*/
	public static Map<String, Object> getVariablesAndValuesFromObject(Class<?> clazz, Object object)
	throws IllegalAccessException {
	Map<String, Object> map = new HashMap<>();
	Field[] fields = clazz.getDeclaredFields();
	AccessibleObject.setAccessible(fields, true);
	for (Field field : fields) {
	map.put(field.getName(), field.get(object));
	}
	Class<?> superclass = clazz.getSuperclass();
	if (!Object.class.equals(superclass)) {
	map.putAll(getVariablesAndValuesFromObject(superclass, object));
	}
	return map;
	}

	/**
	* Convenience method to set values to variables in objects that don't have setters
	*/
	public static void setVariableValueToObject(Object object, String variable, Object value)
	throws IllegalAccessException {
	Field field = ReflectionUtils.getFieldByNameIncludingSuperclasses(variable, object.getClass());
	Objects.requireNonNull(field, "Field " + variable + " not found");
	field.setAccessible(true);
	field.set(object, value);
	}

	static class WrapEvaluator implements TypeAwareExpressionEvaluator {

	private final PlexusContainer container;
	private final TypeAwareExpressionEvaluator evaluator;

	WrapEvaluator(PlexusContainer container, TypeAwareExpressionEvaluator evaluator) {
	this.container = container;
	this.evaluator = evaluator;
	}

	@Override
	public Object evaluate(String expression) throws ExpressionEvaluationException {
	return evaluate(expression, null);
	}

	@Override
	public Object evaluate(String expression, Class<?> type) throws ExpressionEvaluationException {
	Object value = evaluator.evaluate(expression, type);
	if (value == null) {
	String expr = stripTokens(expression);
	if (expr != null) {
	try {
	value = container.lookup(type, expr);
	} catch (ComponentLookupException e) {
	// nothing
	}
	}
	}
	return value;
	}

	private String stripTokens(String expr) {
	if (expr.startsWith("${") && expr.endsWith("}")) {
	return expr.substring(2, expr.length() - 1);
	}
	return null;
	}

	@Override
	public File alignToBaseDirectory(File path) {
	return evaluator.alignToBaseDirectory(path);
	}
	}
	}