001    /*
002     * Created on Aug 5, 2010
003     * 
004     * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
005     * the License. You may obtain a copy of the License at
006     * 
007     * http://www.apache.org/licenses/LICENSE-2.0
008     * 
009     * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
010     * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
011     * specific language governing permissions and limitations under the License.
012     * 
013     * Copyright @2010-2011 the original author or authors.
014     */
015    package org.fest.assertions.internal;
016    
017    import static org.fest.util.Strings.isEmpty;
018    
019    import org.fest.assertions.core.AssertionInfo;
020    import org.fest.assertions.error.AssertionErrorFactory;
021    import org.fest.assertions.error.ErrorMessageFactory;
022    import org.fest.assertions.error.ShouldBeEqual;
023    import org.fest.util.Throwables;
024    import org.fest.util.VisibleForTesting;
025    
026    /**
027     * Failure actions.
028     * 
029     * @author Yvonne Wang
030     * @author Alex Ruiz
031     */
032    public class Failures {
033    
034      private static final Failures INSTANCE = new Failures();
035    
036      /**
037       * Returns the singleton instance of this class.
038       * @return the singleton instance of this class.
039       */
040      public static Failures instance() {
041        return INSTANCE;
042      }
043    
044      /**
045       * flag indicating wether or not we remove elements related to Fest from assertion error stack trace.
046       */
047      private boolean removeFestRelatedElementsFromStackTrace = true;
048    
049      /**
050       * Sets wether we remove elements related to Fest from assertion error stack trace.
051       * @param removeFestRelatedElementsFromStackTrace flag 
052       */
053      public void setRemoveFestRelatedElementsFromStackTrace(boolean removeFestRelatedElementsFromStackTrace) {
054        this.removeFestRelatedElementsFromStackTrace = removeFestRelatedElementsFromStackTrace;
055      }
056    
057      @VisibleForTesting
058      Failures() {}
059    
060      /**
061       * Creates a <code>{@link AssertionError}</code> following this pattern:
062       * <ol>
063       * <li>creates a <code>{@link AssertionError}</code> using <code>{@link AssertionInfo#overridingErrorMessage()}</code>
064       * as the error message if such value is not {@code null}, or</li>
065       * <li>uses the given <code>{@link AssertionErrorFactory}</code> to create an <code>{@link AssertionError}</code>,
066       * prepending the value of <code>{@link AssertionInfo#description()}</code> to the error message</li>
067       * </ol>
068       * @param info contains information about the failed assertion.
069       * @param factory knows how to create {@code AssertionError}s.
070       * @return the created <code>{@link AssertionError}</code>.
071       */
072      public AssertionError failure(AssertionInfo info, AssertionErrorFactory factory) {
073        AssertionError error = failureIfErrorMessageIsOverriden(info);
074        if (error != null) return error;
075        return factory.newAssertionError(info.description());
076      }
077    
078      /**
079       * Creates a <code>{@link AssertionError}</code> following this pattern:
080       * <ol>
081       * <li>creates a <code>{@link AssertionError}</code> using <code>{@link AssertionInfo#overridingErrorMessage()}</code>
082       * as the error message if such value is not {@code null}, or</li>
083       * <li>uses the given <code>{@link ErrorMessageFactory}</code> to create the detail message of the
084       * <code>{@link AssertionError}</code>, prepending the value of <code>{@link AssertionInfo#description()}</code> to
085       * the error message</li>
086       * </ol>
087       * @param info contains information about the failed assertion.
088       * @param message knows how to create detail messages for {@code AssertionError}s.
089       * @return the created <code>{@link AssertionError}</code>.
090       */
091      public AssertionError failure(AssertionInfo info, ErrorMessageFactory message) {
092        AssertionError error = failureIfErrorMessageIsOverriden(info);
093        if (error != null) return error;
094        AssertionError assertionError = new AssertionError(message.create(info.description()));
095        removeFestRelatedElementsFromStackTraceIfNeeded(assertionError);
096        return assertionError;
097      }
098    
099      private AssertionError failureIfErrorMessageIsOverriden(AssertionInfo info) {
100        String overridingErrorMessage = info.overridingErrorMessage();
101        if (!isEmpty(overridingErrorMessage)) return failure(overridingErrorMessage);
102        return null;
103      }
104    
105      /**
106       * Creates a <code>{@link AssertionError}</code> using the given {@code String} as message.
107       * <p>
108       * It filters the AssertionError stack trace be default, to have full stack trace use  {@link #setRemoveFestRelatedElementsFromStackTrace(boolean)}.
109       * @param message the message of the {@code AssertionError} to create.
110       * @return the created <code>{@link AssertionError}</code>.
111       */
112      public AssertionError failure(String message) {
113        AssertionError assertionError = new AssertionError(message);
114        removeFestRelatedElementsFromStackTraceIfNeeded(assertionError);
115        return assertionError;
116      }
117    
118      /**
119       * If is {@link #removeFestRelatedElementsFromStackTrace} is true, it filters the stack trace of the given {@link AssertionError} 
120       * by removing stack trace elements related to Fest in order to get a more readable stack trace.
121       * <p>
122       * See example below :
123       * <pre>
124    --------------- stack trace not filtered -----------------
125    org.junit.ComparisonFailure: expected:<'[Ronaldo]'> but was:<'[Messi]'>
126      at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
127      at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
128      at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
129      at java.lang.reflect.Constructor.newInstance(Constructor.java:501)
130      at org.fest.assertions.error.ConstructorInvoker.newInstance(ConstructorInvoker.java:34)
131      at org.fest.assertions.error.ShouldBeEqual.newComparisonFailure(ShouldBeEqual.java:111)
132      at org.fest.assertions.error.ShouldBeEqual.comparisonFailure(ShouldBeEqual.java:103)
133      at org.fest.assertions.error.ShouldBeEqual.newAssertionError(ShouldBeEqual.java:81)
134      at org.fest.assertions.internal.Failures.failure(Failures.java:76)
135      at org.fest.assertions.internal.Objects.assertEqual(Objects.java:116)
136      at org.fest.assertions.api.AbstractAssert.isEqualTo(AbstractAssert.java:74)
137      at examples.StackTraceFilterExample.main(StackTraceFilterExample.java:13)
138      
139    --------------- stack trace filtered -----------------
140    org.junit.ComparisonFailure: expected:<'[Ronaldo]'> but was:<'[Messi]'>
141      at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
142      at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
143      at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
144      at examples.StackTraceFilterExample.main(StackTraceFilterExample.java:20)
145       * </pre>
146       * 
147       * Method is public because we need to call it from {@link ShouldBeEqual#newAssertionError(org.fest.assertions.description.Description)} that is building a junit ComparisonFailure by reflection. 
148       *  
149       * @param assertionError the {@code AssertionError} to filter stack trace if option is set.
150       */
151      public void removeFestRelatedElementsFromStackTraceIfNeeded(AssertionError assertionError) {
152        if (removeFestRelatedElementsFromStackTrace) {
153          Throwables.removeFestRelatedElementsFromStackTrace(assertionError);
154        }
155      }
156    
157    }