It appears as if your JDK does not supply a working agent attachment mechanism.
Java : 1.8
JVM vendor name : Oracle Corporation
JVM vendor version : 25.251-b08
JVM name : Java HotSpot(TM) 64-Bit Server VM
JVM version : 1.8.0_251-b08
JVM info : mixed mode
OS name : Mac OS X
OS version : 10.15.7
Caused by: java.lang.NoClassDefFoundError: net/bytebuddy/agent/ByteBuddyAgent
at org.mockito.internal.creation.bytebuddy.InlineByteBuddyMockMaker.<clinit>(InlineByteBuddyMockMaker.java:117)
... 41 more
Caused by: java.lang.ClassNotFoundException: net.bytebuddy.agent.ByteBuddyAgent
at java.net.URLClassLoader.findClass(URLClassLoader.java:382)
at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:355)
at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
... 42 more
Failed to load interface org.mockito.plugins.MockMaker implementation declared in sun.misc.CompoundEnumeration@290dbf4