org.junit.jupiter.params.provider.EmptyArgumentsProvider Maven / Gradle / Ivy
/*
* Copyright 2015-2020 the original author or authors.
*
* All rights reserved. This program and the accompanying materials are
* made available under the terms of the Eclipse Public License v2.0 which
* accompanies this distribution and is available at
*
* https://www.eclipse.org/legal/epl-v20.html
*/
package org.junit.jupiter.params.provider;
import static org.junit.jupiter.params.provider.Arguments.arguments;
import java.lang.reflect.Array;
import java.lang.reflect.Method;
import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.Set;
import java.util.stream.Stream;
import org.junit.jupiter.api.extension.ExtensionContext;
import org.junit.platform.commons.PreconditionViolationException;
import org.junit.platform.commons.util.Preconditions;
/**
* @since 5.4
* @see EmptySource
*/
class EmptyArgumentsProvider implements ArgumentsProvider {
@Override
public Stream provideArguments(ExtensionContext context) {
Method testMethod = context.getRequiredTestMethod();
Class[] parameterTypes = testMethod.getParameterTypes();
Preconditions.condition(parameterTypes.length > 0, () -> String.format(
"@EmptySource cannot provide an empty argument to method [%s]: the method does not declare any formal parameters.",
testMethod.toGenericString()));
Class parameterType = parameterTypes[0];
if (String.class.equals(parameterType)) {
return Stream.of(arguments(""));
}
if (List.class.equals(parameterType)) {
return Stream.of(arguments(Collections.emptyList()));
}
if (Set.class.equals(parameterType)) {
return Stream.of(arguments(Collections.emptySet()));
}
if (Map.class.equals(parameterType)) {
return Stream.of(arguments(Collections.emptyMap()));
}
if (parameterType.isArray()) {
Object array = Array.newInstance(parameterType.getComponentType(), 0);
return Stream.of(arguments(array));
}
// else
throw new PreconditionViolationException(
String.format("@EmptySource cannot provide an empty argument to method [%s]: [%s] is not a supported type.",
testMethod.toGenericString(), parameterType.getName()));
}
}