001 /*
002 * Created on Jul 15, 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.core;
016
017 import java.util.Comparator;
018
019 /**
020 * Base contract of all assertion objects: the minimum functionality that any assertion object should provide.
021 * @param <S> the "self" type of this assertion class. Please read "<a href="http://bit.ly/anMa4g"
022 * target="_blank">Emulating 'self types' using Java Generics to simplify fluent API implementation</a>"
023 * for more details.
024 * @param <A> the type of the "actual" value.
025 *
026 * @author Yvonne Wang
027 * @author Alex Ruiz
028 * @author Nicolas François
029 */
030 public interface Assert<S, A> extends Descriptable<S>, ExtensionPoints<S, A> {
031
032 /**
033 * Verifies that the actual value is equal to the given one.
034 * @param expected the given value to compare the actual value to.
035 * @return {@code this} assertion object.
036 * @throws AssertionError if the actual value is not equal to the given one.
037 */
038 S isEqualTo(A expected);
039
040 /**
041 * Verifies that the actual value is not equal to the given one.
042 * @param other the given value to compare the actual value to.
043 * @return {@code this} assertion object.
044 * @throws AssertionError if the actual value is equal to the given one.
045 */
046 S isNotEqualTo(A other);
047
048 /**
049 * Verifies that the actual value is {@code null}.
050 * @throws AssertionError if the actual value is not {@code null}.
051 */
052 void isNull();
053
054 /**
055 * Verifies that the actual value is not {@code null}.
056 * @return {@code this} assertion object.
057 * @throws AssertionError if the actual value is {@code null}.
058 */
059 S isNotNull();
060
061 /**
062 * Verifies that the actual value is the same as the given one.
063 * @param expected the given value to compare the actual value to.
064 * @return {@code this} assertion object.
065 * @throws AssertionError if the actual value is not the same as the given one.
066 */
067 S isSameAs(A expected);
068
069 /**
070 * Verifies that the actual value is not the same as the given one.
071 * @param other the given value to compare the actual value to.
072 * @return {@code this} assertion object.
073 * @throws AssertionError if the actual value is the same as the given one.
074 */
075 S isNotSameAs(A other);
076
077 /**
078 * Verifies that the actual value is present in the given array of values.
079 * @param values the given array to search the actual value in.
080 * @return {@code this} assertion object.
081 * @throws NullPointerException if the given array is {@code null}.
082 * @throws IllegalArgumentException if the given array is empty.
083 * @throws AssertionError if the actual value is not present in the given array.
084 */
085 S isIn(A... values);
086
087 /**
088 * Verifies that the actual value is not present in the given array of values.
089 * @param values the given array to search the actual value in.
090 * @return {@code this} assertion object.
091 * @throws NullPointerException if the given array is {@code null}.
092 * @throws IllegalArgumentException if the given array is empty.
093 * @throws AssertionError if the actual value is present in the given array.
094 */
095 S isNotIn(A... values);
096
097 /**
098 * Verifies that the actual value is present in the given values.
099 * @param values the given iterable to search the actual value in.
100 * @return {@code this} assertion object.
101 * @throws NullPointerException if the given collection is {@code null}.
102 * @throws IllegalArgumentException if the given collection is empty.
103 * @throws AssertionError if the actual value is not present in the given collection.
104 */
105 S isIn(Iterable<? extends A> values);
106
107 /**
108 * Verifies that the actual value is not present in the given values.
109 * @param values the given iterable to search the actual value in.
110 * @return {@code this} assertion object.
111 * @throws NullPointerException if the given collection is {@code null}.
112 * @throws IllegalArgumentException if the given collection is empty.
113 * @throws AssertionError if the actual value is present in the given collection.
114 */
115 S isNotIn(Iterable<? extends A> values);
116
117 /**
118 * Use given custom comparator instead of relying on actual type A equals method for incoming assertion checks.<br>
119 * Custom comparator is bound to assertion instance, meaning that if a new assertion is created, it will use default
120 * comparison strategy. </p> Example :
121 *
122 * <pre>
123 * // compares invoices by payee
124 * assertThat(invoiceList).usingComparator(invoicePayeeComparator).isEqualTo(expectedInvoiceList).
125 *
126 * // compares invoices by date, doesNotHaveDuplicates and contains both use the given invoice date comparator
127 * assertThat(invoiceList).usingComparator(invoiceDateComparator).doesNotHaveDuplicates().contains(may2010Invoice)
128 *
129 * // as assertThat(invoiceList) creates a new assertion, it uses standard comparison strategy (Invoice's equal method) to compare invoiceList elements to lowestInvoice.
130 * assertThat(invoiceList).contains(lowestInvoice).
131 * </pre>
132 *
133 * Custom comparator is not parameterized with actual type A (ie. Comparator<A>) because if it was, we could not
134 * write the following code :
135 *
136 * <pre>
137 * // frodo and sam are instances of Character (a Character having a Race)
138 * // raceComparator implements Comparator<Character>
139 * // assertThat(frodo) returns an ObjectAssert and not a custom CharacterAssert implementing Assert<CharacterAssert, Character>
140 * assertThat(frodo).usingComparator(raceComparator).isEqualTo(sam); // won't compile !
141 *
142 * The code does not compile because assertThat(frodo) returns an ObjectAssert, thus usingComparator expects a Comparator<Object>
143 * and Comparator<Character> is not a Comparator<Object> as generics are not reified.
144 *
145 * Note that, it would have worked if assertThat(frodo) returned a CharacterAssert implementing Assert<CharacterAssert, Character>.
146 * </pre>
147 *
148 * @param customComparator the comparator to use for incoming assertion checks.
149 * @throws NullPointerException if the given comparator is {@code null}.
150 * @return {@code this} assertion object.
151 */
152 S usingComparator(Comparator<?> customComparator);
153
154 /**
155 * Revert to standard comparison for incoming assertion checks.<br>
156 * This method should be used to disable a custom comparison strategy set by calling
157 * {@link #usingComparator(Comparator)}.
158 * @return {@code this} assertion object.
159 */
160 S usingDefaultComparator();
161
162 /**
163 * Throws <code>{@link UnsupportedOperationException}</code> if called. It is easy to accidentally call
164 * <code>{@link #equals(Object)}</code> instead of <code>isEqualTo</code>.
165 * @throws UnsupportedOperationException if this method is called.
166 */
167 @Override boolean equals(Object obj);
168 }