[MNG-11449] Add Mockito javaagent for maven-cli tests

impl/maven-cli/pom.xml

@@ -308,6 +308,7 @@ under the License.
         <groupId>org.apache.maven.plugins</groupId>
         <artifactId>maven-surefire-plugin</artifactId>
         <configuration>
+          <argLine>-Xmx256m @{jacocoArgLine} -javaagent:${org.mockito:mockito-core:jar}</argLine>
           <properties>
             <configurationParameters>junit.jupiter.testclass.order.default = org.junit.jupiter.api.ClassOrderer$OrderAnnotation</configurationParameters>
           </properties>

impl/maven-cli/src/test/java/org/apache/maven/cling/invoker/mvnup/goals/MockitoAgentConfigurationTest.java

@@ -0,0 +1,41 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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.
+ */
+package org.apache.maven.cling.invoker.mvnup.goals;
+
+import java.lang.management.ManagementFactory;
+import java.util.List;
+
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+@DisplayName("Mockito agent configuration")
+class MockitoAgentConfigurationTest {
+
+    @Test
+    @DisplayName("should run tests with mockito configured as javaagent")
+    void shouldRunTestsWithMockitoAsJavaAgent() {
+        List<String> inputArguments = ManagementFactory.getRuntimeMXBean().getInputArguments();
+
+        assertTrue(
+                inputArguments.stream().anyMatch(a -> a.startsWith("-javaagent:") && a.contains("mockito-core")),
+                () -> "Expected Mockito javaagent in JVM arguments, but got: " + inputArguments);
+    }
+}