Add doesNotMatch predicate and DoesNotMatchPredicateTest

assertj-core/src/main/java/org/assertj/core/api/AbstractAssert.java

@@ -19,6 +19,7 @@
 import static org.assertj.core.description.Description.mostRelevantDescription;
 import static org.assertj.core.error.ShouldMatch.shouldMatch;
 import static org.assertj.core.error.ShouldNotBeNull.shouldNotBeNull;
+import static org.assertj.core.error.ShouldNotMatch.shouldNotMatch;
 import static org.assertj.core.extractor.Extractors.byName;
 import static org.assertj.core.extractor.Extractors.extractedDescriptionOf;
 import static org.assertj.core.util.Lists.list;
@@ -809,6 +810,48 @@ public SELF matches(Predicate<? super ACTUAL> predicate, String predicateDescrip
     return matches(predicate, new PredicateDescription(predicateDescription));
   }
 
+  /**
+   * Verifies that the actual object does not match the given predicate.
+   * <p>
+   * Example :
+   *
+   * <pre><code class='java'> assertThat(player).doesNotMatch(p -&gt; p.isRookie());</code></pre>
+   *
+   * @param predicate the {@link Predicate} to check does not match
+   * @return {@code this} assertion object.
+   * @throws AssertionError if {@code actual} does match the given {@link Predicate}.
+   * @throws NullPointerException if given {@link Predicate} is null.
+   */
+  public SELF doesNotMatch(Predicate<? super ACTUAL> predicate) {
+    // use default PredicateDescription
+    return doesNotMatch(predicate, PredicateDescription.GIVEN);
+  }
+
+  /**
+   * Verifies that the actual object does not match the given predicate, the predicate description is used to get an
+   * informative error message.
+   * <p>
+   * Example :
+   *
+   * <pre><code class='java'> assertThat(player).doesNotMatch(p -&gt; p.isRookie(), "is not rookie");</code></pre>
+   *
+   * The error message contains the predicate description, if the previous assertion fails, it will be:
+   *
+   * <pre><code class='java'> Expecting:
+   *   &lt;player&gt;
+   * to not match 'is rookie' predicate.</code></pre>
+   *
+   * @param predicate the {@link Predicate} to check does not match
+   * @param predicateDescription a description of the {@link Predicate} used in the error message
+   * @return {@code this} assertion object.
+   * @throws AssertionError if {@code actual} does match the given {@link Predicate}.
+   * @throws NullPointerException if given {@link Predicate} is null.
+   * @throws NullPointerException if given predicateDescription is null.
+   */
+  public SELF doesNotMatch(Predicate<? super ACTUAL> predicate, String predicateDescription) {
+    return doesNotMatch(predicate, new PredicateDescription(predicateDescription));
+  }
+
   /**
    * Verifies that the actual object satisfied the given requirements expressed as {@link Consumer}s.
    * <p>
@@ -1029,6 +1072,12 @@ private SELF matches(Predicate<? super ACTUAL> predicate, PredicateDescription p
     throw Failures.instance().failure(info, shouldMatch(actual, predicate, predicateDescription));
   }
 
+  private SELF doesNotMatch(Predicate<? super ACTUAL> predicate, PredicateDescription predicateDescription) {
+    requireNonNull(predicate, "The predicate must not be null");
+    if (!predicate.test(actual)) return myself;
+    throw Failures.instance().failure(info, shouldNotMatch(actual, predicate, predicateDescription));
+  }
+
   public static void setCustomRepresentation(Representation customRepresentation) {
     ConfigurationProvider.loadRegisteredConfiguration();
     AbstractAssert.customRepresentation = customRepresentation;

assertj-core/src/test/java/org/assertj/core/condition/DoesNotMatchPredicateTest.java

@@ -0,0 +1,92 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License is distributed on
+ * an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the
+ * specific language governing permissions and limitations under the License.
+ *
+ * Copyright 2012-2024 the original author or authors.
+ */
+package org.assertj.core.condition;
+
+import static java.lang.String.format;
+import static org.assertj.core.internal.ErrorMessages.predicateIsNull;
+
+import org.assertj.core.api.WithAssertions;
+import org.assertj.core.testkit.Jedi;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+class DoesNotMatchPredicateTest implements WithAssertions {
+
+  private Jedi yoda;
+
+  @BeforeEach
+  public void setup() {
+    yoda = new Jedi("Yoda", "Green");
+  }
+
+  @Test
+  void should_not_match_predicate() {
+    assertThat(yoda).doesNotMatch(x -> x.lightSaberColor.equals("Blue"));
+  }
+
+  @Test
+  void should_not_match_predicate_with_description() {
+    assertThat(yoda).doesNotMatch(x -> x.lightSaberColor.equals("Blue"), "has blue light saber");
+  }
+
+  @Test
+  void should_fail_if_object_does_match_predicate() {
+    assertThatExceptionOfType(AssertionError.class).isThrownBy(() -> assertThat(yoda).doesNotMatch(x -> x.lightSaberColor.equals("Green")))
+      .withMessage(format("%n" +
+        "Expecting actual:%n" +
+        "  Yoda the Jedi%n" +
+        "not to match given predicate.%n" +
+        "%n" +
+        "You can use 'doesNotMatch(Predicate p, String description)' to have a better error message%n"
+        +
+        "For example:%n" +
+        "  assertThat(player).doesNotMatch(p -> p.isRookie(), \"is not rookie\");%n"
+        +
+        "will give an error message looking like:%n" +
+        "%n" +
+        "Expecting actual:%n" +
+        "  player%n" +
+        "not to match 'is not rookie' predicate"));
+  }
+
+  @Test
+  void should_fail_if_object_does_match_predicate_and_use_predicate_description_in_error_message() {
+    assertThatExceptionOfType(AssertionError.class).isThrownBy(() -> assertThat(yoda).as("check light saber")
+        .doesNotMatch(x -> x.lightSaberColor.equals("Green"),
+          "has red light saber"))
+      .withMessage(format("[check light saber] %n" +
+        "Expecting actual:%n" +
+        "  Yoda the Jedi%n" +
+        "not to match 'has red light saber' predicate."));
+  }
+
+  @Test
+  void should_fail_if_given_predicate_is_null() {
+    assertThatNullPointerException().isThrownBy(() -> assertThat(yoda).matches(null))
+      .withMessage(predicateIsNull());
+  }
+
+  @Test
+  void should_fail_if_given_predicate_with_description_is_null() {
+    assertThatNullPointerException().isThrownBy(() -> assertThat(yoda).matches(null,
+        "whatever ..."))
+      .withMessage(predicateIsNull());
+  }
+
+  @Test
+  void should_fail_if_given_predicate_description_is_null() {
+    assertThatNullPointerException().isThrownBy(() -> assertThat(yoda).matches(x -> x.lightSaberColor.equals("Green"),
+        null))
+      .withMessage("The predicate description must not be null");
+  }
+}