convert API/server tests to mockito (#8848)

* convert API tests to mockito

* convert server tests to mockito

* add co-author

build.gradle.kts

@@ -38,6 +38,8 @@ subprojects {
             exceptionFormat = TestExceptionFormat.FULL
             events(TestLogEvent.STANDARD_OUT)
         }
+        minHeapSize = "2g"
+        maxHeapSize = "2g"
     }
 
     repositories {