Fiddling to make Mockito work on modern JVMs.

core/pom.xml

@@ -22,19 +22,21 @@
     <dependency>
       <groupId>org.mockito</groupId>
       <artifactId>mockito-core</artifactId>
-      <version>3.12.4</version>
+      <version>5.18.0</version>
       <scope>test</scope>
     </dependency>
   </dependencies>
 
+  <properties>
     <!-- By default, no host whitelist is added to the binary, so it can be used
          to download and run applications from any server. To create a custom
          Getdown build that can only talk to whitelisted servers, set this
          property on the command line, e.g. -Dgetdown.host.whitelist=my.server.com
          Wildcards can be used (*.mycompany.com) and multiple values can be
          separated by commas (app1.foo.com,app2.bar.com,app3.baz.com). -->
-  <properties>
     <getdown.host.whitelist />
+    <!-- This is needed for Mockito's agent config shenanigans below. -->
+    <argLine/>
   </properties>
 
   <build>
@@ -126,6 +128,27 @@
           <useFile>false</useFile>
         </configuration>
       </plugin>
+
+      <!-- this is needed to set the property in the below argLine config -->
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-dependency-plugin</artifactId>
+        <executions>
+          <execution>
+            <goals>
+              <goal>properties</goal>
+            </goals>
+          </execution>
+        </executions>
+      </plugin>
+
+      <plugin>
+        <groupId>org.apache.maven.plugins</groupId>
+        <artifactId>maven-surefire-plugin</artifactId>
+        <configuration>
+          <argLine>@{argLine} -javaagent:${org.mockito:mockito-core:jar}</argLine>
+        </configuration>
+      </plugin>
     </plugins>
   </build>