org.junit.runners.BlockJUnit4ClassRunner Maven / Gradle / Ivy
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package org.junit.runners;
import static org.junit.internal.runners.rules.RuleMemberValidator.RULE_METHOD_VALIDATOR;
import static org.junit.internal.runners.rules.RuleMemberValidator.RULE_VALIDATOR;
import java.util.List;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.TimeUnit;
import org.junit.After;
import org.junit.Before;
import org.junit.Ignore;
import org.junit.Rule;
import org.junit.Test;
import org.junit.Test.None;
import org.junit.internal.runners.model.ReflectiveCallable;
import org.junit.internal.runners.statements.ExpectException;
import org.junit.internal.runners.statements.Fail;
import org.junit.internal.runners.statements.FailOnTimeout;
import org.junit.internal.runners.statements.InvokeMethod;
import org.junit.internal.runners.statements.RunAfters;
import org.junit.internal.runners.statements.RunBefores;
import org.junit.rules.MethodRule;
import org.junit.rules.RunRules;
import org.junit.rules.TestRule;
import org.junit.runner.Description;
import org.junit.runner.notification.RunNotifier;
import org.junit.runners.model.FrameworkMethod;
import org.junit.runners.model.InitializationError;
import org.junit.runners.model.MultipleFailureException;
import org.junit.runners.model.Statement;
/**
* Implements the JUnit 4 standard test case class model, as defined by the
* annotations in the org.junit package. Many users will never notice this
* class: it is now the default test class runner, but it should have exactly
* the same behavior as the old test class runner ({@code JUnit4ClassRunner}).
*
* BlockJUnit4ClassRunner has advantages for writers of custom JUnit runners
* that are slight changes to the default behavior, however:
*
*
* - It has a much simpler implementation based on {@link Statement}s,
* allowing new operations to be inserted into the appropriate point in the
* execution flow.
*
*
- It is published, and extension and reuse are encouraged, whereas {@code
* JUnit4ClassRunner} was in an internal package, and is now deprecated.
*
*
* In turn, in 2009 we introduced {@link Rule}s. In many cases where extending
* BlockJUnit4ClassRunner was necessary to add new behavior, {@link Rule}s can
* be used, which makes the extension more reusable and composable.
*
* @since 4.5
*/
public class BlockJUnit4ClassRunner extends ParentRunner {
private final ConcurrentHashMap methodDescriptions = new ConcurrentHashMap();
/**
* Creates a BlockJUnit4ClassRunner to run {@code klass}
*
* @throws InitializationError if the test class is malformed.
*/
public BlockJUnit4ClassRunner(Class klass) throws InitializationError {
super(klass);
}
//
// Implementation of ParentRunner
//
@Override
protected void runChild(final FrameworkMethod method, RunNotifier notifier) {
Description description = describeChild(method);
if (isIgnored(method)) {
notifier.fireTestIgnored(description);
} else {
runLeaf(methodBlock(method), description, notifier);
}
}
/**
* Evaluates whether {@link FrameworkMethod}s are ignored based on the
* {@link Ignore} annotation.
*/
@Override
protected boolean isIgnored(FrameworkMethod child) {
return child.getAnnotation(Ignore.class) != null;
}
@Override
protected Description describeChild(FrameworkMethod method) {
Description description = methodDescriptions.get(method);
if (description == null) {
description = Description.createTestDescription(getTestClass().getJavaClass(),
testName(method), method.getAnnotations());
methodDescriptions.putIfAbsent(method, description);
}
return description;
}
@Override
protected List getChildren() {
return computeTestMethods();
}
//
// Override in subclasses
//
/**
* Returns the methods that run tests. Default implementation returns all
* methods annotated with {@code @Test} on this class and superclasses that
* are not overridden.
*/
protected List computeTestMethods() {
return getTestClass().getAnnotatedMethods(Test.class);
}
@Override
protected void collectInitializationErrors(List errors) {
super.collectInitializationErrors(errors);
validateNoNonStaticInnerClass(errors);
validateConstructor(errors);
validateInstanceMethods(errors);
validateFields(errors);
validateMethods(errors);
}
protected void validateNoNonStaticInnerClass(List errors) {
if (getTestClass().isANonStaticInnerClass()) {
String gripe = "The inner class " + getTestClass().getName()
+ " is not static.";
errors.add(new Exception(gripe));
}
}
/**
* Adds to {@code errors} if the test class has more than one constructor,
* or if the constructor takes parameters. Override if a subclass requires
* different validation rules.
*/
protected void validateConstructor(List errors) {
validateOnlyOneConstructor(errors);
validateZeroArgConstructor(errors);
}
/**
* Adds to {@code errors} if the test class has more than one constructor
* (do not override)
*/
protected void validateOnlyOneConstructor(List errors) {
if (!hasOneConstructor()) {
String gripe = "Test class should have exactly one public constructor";
errors.add(new Exception(gripe));
}
}
/**
* Adds to {@code errors} if the test class's single constructor takes
* parameters (do not override)
*/
protected void validateZeroArgConstructor(List errors) {
if (!getTestClass().isANonStaticInnerClass()
&& hasOneConstructor()
&& (getTestClass().getOnlyConstructor().getParameterTypes().length != 0)) {
String gripe = "Test class should have exactly one public zero-argument constructor";
errors.add(new Exception(gripe));
}
}
private boolean hasOneConstructor() {
return getTestClass().getJavaClass().getConstructors().length == 1;
}
/**
* Adds to {@code errors} for each method annotated with {@code @Test},
* {@code @Before}, or {@code @After} that is not a public, void instance
* method with no arguments.
*/
@Deprecated
protected void validateInstanceMethods(List errors) {
validatePublicVoidNoArgMethods(After.class, false, errors);
validatePublicVoidNoArgMethods(Before.class, false, errors);
validateTestMethods(errors);
if (computeTestMethods().size() == 0) {
errors.add(new Exception("No runnable methods"));
}
}
protected void validateFields(List errors) {
RULE_VALIDATOR.validate(getTestClass(), errors);
}
private void validateMethods(List errors) {
RULE_METHOD_VALIDATOR.validate(getTestClass(), errors);
}
/**
* Adds to {@code errors} for each method annotated with {@code @Test}that
* is not a public, void instance method with no arguments.
*/
protected void validateTestMethods(List errors) {
validatePublicVoidNoArgMethods(Test.class, false, errors);
}
/**
* Returns a new fixture for running a test. Default implementation executes
* the test class's no-argument constructor (validation should have ensured
* one exists).
*/
protected Object createTest() throws Exception {
return getTestClass().getOnlyConstructor().newInstance();
}
/**
* Returns the name that describes {@code method} for {@link Description}s.
* Default implementation is the method's name
*/
protected String testName(FrameworkMethod method) {
return method.getName();
}
/**
* Returns a Statement that, when executed, either returns normally if
* {@code method} passes, or throws an exception if {@code method} fails.
*
* Here is an outline of the default implementation:
*
*
* - Invoke {@code method} on the result of {@code createTest()}, and
* throw any exceptions thrown by either operation.
*
- HOWEVER, if {@code method}'s {@code @Test} annotation has the {@code
* expecting} attribute, return normally only if the previous step threw an
* exception of the correct type, and throw an exception otherwise.
*
- HOWEVER, if {@code method}'s {@code @Test} annotation has the {@code
* timeout} attribute, throw an exception if the previous step takes more
* than the specified number of milliseconds.
*
- ALWAYS run all non-overridden {@code @Before} methods on this class
* and superclasses before any of the previous steps; if any throws an
* Exception, stop execution and pass the exception on.
*
- ALWAYS run all non-overridden {@code @After} methods on this class
* and superclasses after any of the previous steps; all After methods are
* always executed: exceptions thrown by previous steps are combined, if
* necessary, with exceptions from After methods into a
* {@link MultipleFailureException}.
*
- ALWAYS allow {@code @Rule} fields to modify the execution of the
* above steps. A {@code Rule} may prevent all execution of the above steps,
* or add additional behavior before and after, or modify thrown exceptions.
* For more information, see {@link TestRule}
*
*
* This can be overridden in subclasses, either by overriding this method,
* or the implementations creating each sub-statement.
*/
protected Statement methodBlock(FrameworkMethod method) {
Object test;
try {
test = new ReflectiveCallable() {
@Override
protected Object runReflectiveCall() throws Throwable {
return createTest();
}
}.run();
} catch (Throwable e) {
return new Fail(e);
}
Statement statement = methodInvoker(method, test);
statement = possiblyExpectingExceptions(method, test, statement);
statement = withPotentialTimeout(method, test, statement);
statement = withBefores(method, test, statement);
statement = withAfters(method, test, statement);
statement = withRules(method, test, statement);
return statement;
}
//
// Statement builders
//
/**
* Returns a {@link Statement} that invokes {@code method} on {@code test}
*/
protected Statement methodInvoker(FrameworkMethod method, Object test) {
return new InvokeMethod(method, test);
}
/**
* Returns a {@link Statement}: if {@code method}'s {@code @Test} annotation
* has the {@code expecting} attribute, return normally only if {@code next}
* throws an exception of the correct type, and throw an exception
* otherwise.
*/
protected Statement possiblyExpectingExceptions(FrameworkMethod method,
Object test, Statement next) {
Test annotation = method.getAnnotation(Test.class);
return expectsException(annotation) ? new ExpectException(next,
getExpectedException(annotation)) : next;
}
/**
* Returns a {@link Statement}: if {@code method}'s {@code @Test} annotation
* has the {@code timeout} attribute, throw an exception if {@code next}
* takes more than the specified number of milliseconds.
*/
@Deprecated
protected Statement withPotentialTimeout(FrameworkMethod method,
Object test, Statement next) {
long timeout = getTimeout(method.getAnnotation(Test.class));
if (timeout <= 0) {
return next;
}
return FailOnTimeout.builder()
.withTimeout(timeout, TimeUnit.MILLISECONDS)
.build(next);
}
/**
* Returns a {@link Statement}: run all non-overridden {@code @Before}
* methods on this class and superclasses before running {@code next}; if
* any throws an Exception, stop execution and pass the exception on.
*/
protected Statement withBefores(FrameworkMethod method, Object target,
Statement statement) {
List befores = getTestClass().getAnnotatedMethods(
Before.class);
return befores.isEmpty() ? statement : new RunBefores(statement,
befores, target);
}
/**
* Returns a {@link Statement}: run all non-overridden {@code @After}
* methods on this class and superclasses before running {@code next}; all
* After methods are always executed: exceptions thrown by previous steps
* are combined, if necessary, with exceptions from After methods into a
* {@link MultipleFailureException}.
*/
protected Statement withAfters(FrameworkMethod method, Object target,
Statement statement) {
List afters = getTestClass().getAnnotatedMethods(
After.class);
return afters.isEmpty() ? statement : new RunAfters(statement, afters,
target);
}
private Statement withRules(FrameworkMethod method, Object target,
Statement statement) {
List testRules = getTestRules(target);
Statement result = statement;
result = withMethodRules(method, testRules, target, result);
result = withTestRules(method, testRules, result);
return result;
}
private Statement withMethodRules(FrameworkMethod method, List testRules,
Object target, Statement result) {
for (org.junit.rules.MethodRule each : getMethodRules(target)) {
if (!testRules.contains(each)) {
result = each.apply(result, method, target);
}
}
return result;
}
private List getMethodRules(Object target) {
return rules(target);
}
/**
* @param target the test case instance
* @return a list of MethodRules that should be applied when executing this
* test
*/
protected List rules(Object target) {
List rules = getTestClass().getAnnotatedMethodValues(target,
Rule.class, MethodRule.class);
rules.addAll(getTestClass().getAnnotatedFieldValues(target,
Rule.class, MethodRule.class));
return rules;
}
/**
* Returns a {@link Statement}: apply all non-static fields
* annotated with {@link Rule}.
*
* @param statement The base statement
* @return a RunRules statement if any class-level {@link Rule}s are
* found, or the base statement
*/
private Statement withTestRules(FrameworkMethod method, List testRules,
Statement statement) {
return testRules.isEmpty() ? statement :
new RunRules(statement, testRules, describeChild(method));
}
/**
* @param target the test case instance
* @return a list of TestRules that should be applied when executing this
* test
*/
protected List getTestRules(Object target) {
List result = getTestClass().getAnnotatedMethodValues(target,
Rule.class, TestRule.class);
result.addAll(getTestClass().getAnnotatedFieldValues(target,
Rule.class, TestRule.class));
return result;
}
private Class getExpectedException(Test annotation) {
if (annotation == null || annotation.expected() == None.class) {
return null;
} else {
return annotation.expected();
}
}
private boolean expectsException(Test annotation) {
return getExpectedException(annotation) != null;
}
private long getTimeout(Test annotation) {
if (annotation == null) {
return 0;
}
return annotation.timeout();
}
}