quicktest: speed up running quicktests (#6815)

I intended to write some new VM tests, and the existing VM lifecycle
tests looked like a good starting point.

But it turns out that we stopped running this test completely when we
dropped the `CoreOS` template.

Use a memtest ISO instead of the CoreOS template.

Also optimize various startup and shutdown code in quicktest, because
even a no-op test that did nothing took 14s to run.

Draft PR, because it needs more testing, and I'm not entirely happy with
how the SR filtering works, e.g. this test still won't run if
`-default-sr` is passed (and passing `-default-sr` is very useful during
development because it further cuts down startup time by 5s).

I should then be able to reuse this code in the new tests that I'm
writing.

Author: edwintorok

ocaml/quicktest/qt.ml

@@ -119,22 +119,20 @@ module VM = struct
     let other = "Other install media"
 
     let find rpc session_id startswith =
-      let vms = Client.Client.VM.get_all ~rpc ~session_id in
+      let vms = Client.Client.VM.get_all_records ~rpc ~session_id in
       match
         List.filter
-          (fun self ->
-            String.starts_with ~prefix:startswith
-              (Client.Client.VM.get_name_label ~rpc ~session_id ~self)
-            && Client.Client.VM.get_is_a_template ~rpc ~session_id ~self
+          (fun (_, self) ->
+            String.starts_with ~prefix:startswith self.API.vM_name_label
+            && self.API.vM_is_a_template
           )
           vms
       with
       | [] ->
           None
-      | x :: _ ->
-          Printf.printf "Choosing template with name: %s\n"
-            (Client.Client.VM.get_name_label ~rpc ~session_id ~self:x) ;
-          Some x
+      | (r, vm) :: _ ->
+          Printf.printf "Choosing template with name: %s\n" vm.API.vM_name_label ;
+          Some r
   end
 
   let install rpc session_id ~template ~name ?sr () =

ocaml/quicktest/qt_filter.ml

@@ -17,11 +17,12 @@ let vdi_count = Hashtbl.create 4
 let count_vdis rpc session_id sr =
   Client.Client.SR.scan ~rpc ~session_id ~sr ;
   let managed_vdis =
-    Client.Client.SR.get_VDIs ~rpc ~session_id ~self:sr
+    let expr =
+      Printf.sprintf {|field "SR"="%s" and field "managed" = "true"|}
+        (Ref.string_of sr)
+    in
+    Client.Client.VDI.get_all_records_where ~rpc ~session_id ~expr
     (* NB vhd backends may delete records beneath us *)
-    |> Valid_ref_list.filter (fun vdi ->
-        Client.Client.VDI.get_managed ~rpc ~session_id ~self:vdi
-    )
   in
   List.length managed_vdis
 
@@ -47,7 +48,14 @@ let init () =
   Client.Client.SR.get_all_records ~rpc:!A.rpc ~session_id:!session_id
   |> List.iter (fun (ref, sr) ->
       if test_sr_uuid = "" || sr.API.sR_uuid = test_sr_uuid then
-        if List.mem `scan sr.API.sR_allowed_operations then
+        if
+          List.(
+            mem `scan sr.API.sR_allowed_operations
+            && (mem `vdi_create sr.API.sR_allowed_operations
+               || mem `vdi_destroy sr.API.sR_allowed_operations
+               )
+          )
+        then
           let before = count_vdis !A.rpc !session_id ref in
           Hashtbl.add vdi_count sr.API.sR_uuid before
   )
@@ -61,7 +69,14 @@ let finish () =
       match Hashtbl.find_opt vdi_count sr.API.sR_uuid with
       | Some before ->
           if test_sr_uuid = "" || sr.API.sR_uuid = test_sr_uuid then
-            if List.mem `scan sr.API.sR_allowed_operations then
+            if
+              List.(
+                mem `scan sr.API.sR_allowed_operations
+                && (mem `vdi_create sr.API.sR_allowed_operations
+                   || mem `vdi_destroy sr.API.sR_allowed_operations
+                   )
+              )
+            then
               let after = count_vdis !A.rpc !session_id ref in
               if after <> before then
                 failwith
@@ -264,10 +279,11 @@ module SR = struct
         List.mem `vdi_create sr_info.Qt.allowed_operations
         && List.mem `vdi_destroy sr_info.Qt.allowed_operations
         || not
-             (is_empty
+             (Seq.is_empty
                 (Client.Client.SR.get_VDIs ~rpc:!A.rpc ~session_id:!session_id
                    ~self:sr_info.Qt.sr
-                |> List.filter (fun vdi ->
+                |> List.to_seq
+                |> Seq.filter (fun vdi ->
                     not
                       (Client.Client.VDI.get_missing ~rpc:!A.rpc
                          ~session_id:!session_id ~self:vdi
@@ -346,9 +362,9 @@ module SR = struct
   let list_srs srs = with_xapi_query srs
 
   let f srs tcs =
-    for_each
-      (fun test_case -> List.map (specialise test_case) (list_srs srs))
-      tcs
+    let srs = list_srs srs in
+    if srs = [] then Printf.eprintf "No SRs found that match condition\n" ;
+    for_each (fun test_case -> List.map (specialise test_case) srs) tcs
 end
 
 let sr = SR.f
@@ -358,6 +374,7 @@ let vm_template template_name =
       with_xapi_query @@ fun () ->
       match Qt.VM.Template.find !A.rpc !session_id template_name with
       | None ->
+          Printf.eprintf "Template not found: %S\n" template_name ;
           []
       | Some vm_template ->
           [(name, speed, test vm_template)]