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/*
* Copyright 2015-2023 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.api;
import static org.apiguardian.api.API.Status.STABLE;
import static org.junit.jupiter.api.AssertionUtils.getCanonicalName;
import java.util.function.Supplier;
import org.apiguardian.api.API;
import org.junit.platform.commons.util.StringUtils;
import org.opentest4j.AssertionFailedError;
/**
* Builder for {@link AssertionFailedError AssertionFailedErrors}.
*
* Using this builder ensures consistency in how failure message are formatted
* within JUnit Jupiter and for custom user-defined assertions.
*
* @since 5.9
* @see AssertionFailedError
*/
@API(status = STABLE, since = "5.9")
public class AssertionFailureBuilder {
private Object message;
private Throwable cause;
private boolean mismatch;
private Object expected;
private Object actual;
private String reason;
private boolean includeValuesInMessage = true;
/**
* Create a new {@code AssertionFailureBuilder}.
*/
public static AssertionFailureBuilder assertionFailure() {
return new AssertionFailureBuilder();
}
private AssertionFailureBuilder() {
}
/**
* Set the user-defined message of the assertion.
*
* The {@code message} may be passed as a {@link Supplier} or plain
* {@link String}. If any other type is passed, it is converted to
* {@code String} as per {@link StringUtils#nullSafeToString(Object)}.
*
* @param message the user-defined failure message; may be {@code null}
* @return this builder for method chaining
*/
public AssertionFailureBuilder message(Object message) {
this.message = message;
return this;
}
/**
* Set the reason why the assertion failed.
*
* @param reason the failure reason; may be {@code null}
* @return this builder for method chaining
*/
public AssertionFailureBuilder reason(String reason) {
this.reason = reason;
return this;
}
/**
* Set the cause of the assertion failure.
*
* @param cause the failure cause; may be {@code null}
* @return this builder for method chaining
*/
public AssertionFailureBuilder cause(Throwable cause) {
this.cause = cause;
return this;
}
/**
* Set the expected value of the assertion.
*
* @param expected the expected value; may be {@code null}
* @return this builder for method chaining
*/
public AssertionFailureBuilder expected(Object expected) {
this.mismatch = true;
this.expected = expected;
return this;
}
/**
* Set the actual value of the assertion.
*
* @param actual the actual value; may be {@code null}
* @return this builder for method chaining
*/
public AssertionFailureBuilder actual(Object actual) {
this.mismatch = true;
this.actual = actual;
return this;
}
/**
* Set whether to include the actual and expected values in the generated
* failure message.
*
* @param includeValuesInMessage whether to include the actual and expected
* values
* @return this builder for method chaining
*/
public AssertionFailureBuilder includeValuesInMessage(boolean includeValuesInMessage) {
this.includeValuesInMessage = includeValuesInMessage;
return this;
}
/**
* Build the {@link AssertionFailedError AssertionFailedError} and throw it.
*
* @throws AssertionFailedError always
*/
public void buildAndThrow() throws AssertionFailedError {
throw build();
}
/**
* Build the {@link AssertionFailedError AssertionFailedError} without
* throwing it.
*
* @return the built assertion failure
*/
public AssertionFailedError build() {
String reason = nullSafeGet(this.reason);
if (mismatch && includeValuesInMessage) {
reason = (reason == null ? "" : reason + ", ") + formatValues(expected, actual);
}
String message = nullSafeGet(this.message);
if (reason != null) {
message = buildPrefix(message) + reason;
}
return mismatch //
? new AssertionFailedError(message, expected, actual, cause) //
: new AssertionFailedError(message, cause);
}
private static String nullSafeGet(Object messageOrSupplier) {
if (messageOrSupplier == null) {
return null;
}
if (messageOrSupplier instanceof Supplier) {
Object message = ((Supplier) messageOrSupplier).get();
return StringUtils.nullSafeToString(message);
}
return StringUtils.nullSafeToString(messageOrSupplier);
}
private static String buildPrefix(String message) {
return (StringUtils.isNotBlank(message) ? message + " ==> " : "");
}
private static String formatValues(Object expected, Object actual) {
String expectedString = toString(expected);
String actualString = toString(actual);
if (expectedString.equals(actualString)) {
return String.format("expected: %s but was: %s", formatClassAndValue(expected, expectedString),
formatClassAndValue(actual, actualString));
}
return String.format("expected: <%s> but was: <%s>", expectedString, actualString);
}
private static String formatClassAndValue(Object value, String valueString) {
// If the value is null, return instead of null.
if (value == null) {
return "";
}
String classAndHash = getClassName(value) + toHash(value);
// if it's a class, there's no need to repeat the class name contained in the valueString.
return (value instanceof Class ? "<" + classAndHash + ">" : classAndHash + "<" + valueString + ">");
}
private static String toString(Object obj) {
if (obj instanceof Class) {
return getCanonicalName((Class) obj);
}
return StringUtils.nullSafeToString(obj);
}
private static String toHash(Object obj) {
return (obj == null ? "" : "@" + Integer.toHexString(System.identityHashCode(obj)));
}
private static String getClassName(Object obj) {
return (obj == null ? "null"
: obj instanceof Class ? getCanonicalName((Class) obj) : obj.getClass().getName());
}
}