Fix internal test failures

The adminusers test did not properly initialize all subsystems in
MaxScale. The polling and DCB tests weren't updated with the changes to
the DCB closing.

server/core/dcb.cc

@@ -1950,18 +1950,6 @@ dcb_call_callback(DCB *dcb, DCB_REASON reason)
     }
 }
 
-/**
- * Check the passed DCB to ensure it is in the list of all DCBS
- *
- * @param       dcb     The DCB to check
- * @return      1 if the DCB is in the list, otherwise 0
- */
-int
-dcb_isvalid(DCB *dcb)
-{
-    return !!dcb;
-}
-
 static void dcb_hangup_foreach_worker(int thread_id, struct server* server)
 {
     for (DCB *dcb = this_unit.all_dcbs[thread_id]; dcb; dcb = dcb->thread.next)

server/core/test/testadminusers.cc

@@ -247,6 +247,7 @@ main(int argc, char **argv)
 
     unlink(buf);
 
+    admin_users_init();
     result += test1();
     result += test2();
     result += test3();

server/core/test/testdcb.cc

@@ -35,9 +35,10 @@
 #include <string.h>
 
 #include <maxscale/config.h>
-#include <maxscale/dcb.h>
 #include <maxscale/listener.h>
 
+#include "../dcb.cc"
+
 /**
  * test1    Allocate a dcb and do lots of other things
  *
@@ -48,17 +49,16 @@ test1()
     DCB   *dcb;
     SERV_LISTENER dummy;
     /* Single buffer tests */
-    ss_dfprintf(stderr, "testdcb : creating buffer with type DCB_ROLE_SERVICE_LISTENER");
+    ss_dfprintf(stderr, "testdcb : creating buffer with type DCB_ROLE_INTERNAL");
     dcb = dcb_alloc(DCB_ROLE_INTERNAL, &dummy);
     printDCB(dcb);
-    ss_info_dassert(dcb_isvalid(dcb), "New DCB must be valid");
     ss_dfprintf(stderr, "\t..done\nAllocated dcb.");
     printAllDCBs();
     ss_dfprintf(stderr, "\t..done\n");
     dcb->state = DCB_STATE_POLLING;
+    this_thread.current_dcb = dcb;
     dcb_close(dcb);
     ss_dfprintf(stderr, "Freed original dcb");
-    ss_info_dassert(!dcb_isvalid(dcb), "Closed DCB must not be valid");
     ss_dfprintf(stderr, "\t..done\n");
 
     return 0;

server/core/test/testpoll.cc

@@ -35,6 +35,7 @@
 #include <errno.h>
 #include <maxscale/dcb.h>
 #include <maxscale/listener.h>
+#include <maxscale/service.h>
 
 #include "test_utils.h"
 
@@ -97,6 +98,8 @@ test1()
     sleep(10);
     //TODO, fix this for workers: poll_shutdown();
     ss_dfprintf(stderr, "\t..done\nTidy up.");
+    SERVICE my_service = {};
+    dcb->service = &my_service;
     dcb_close(dcb);
     ss_dfprintf(stderr, "\t..done\n");