diff --git a/tests/qemu-iotests/184 b/tests/qemu-iotests/184
index ee96c99af3..2b68284d58 100755
--- a/tests/qemu-iotests/184
+++ b/tests/qemu-iotests/184
@@ -27,18 +27,12 @@ echo "QA output created by $seq"
 here=`pwd`
 status=1	# failure is the default!
 
-_cleanup()
-{
-    _cleanup_test_img
-}
-trap "_cleanup; exit \$status" 0 1 2 3 15
+trap "exit \$status" 0 1 2 3 15
 
 # get standard environment, filters and checks
 . ./common.rc
 . ./common.filter
 
-_supported_fmt qcow2
-_supported_proto file
 _supported_os Linux
 
 function do_run_qemu()
@@ -55,7 +49,6 @@ function run_qemu()
                           | _filter_actual_image_size
 }
 
-_make_test_img 64M
 test_throttle=$($QEMU_IMG --help|grep throttle)
 [ "$test_throttle" = "" ] && _supported_fmt throttle
 
@@ -66,12 +59,8 @@ run_qemu <<EOF
 { "execute": "qmp_capabilities" }
 { "execute": "blockdev-add",
   "arguments": {
-    "driver": "$IMGFMT",
-    "node-name": "disk0",
-    "file": {
-      "driver": "file",
-      "filename": "$TEST_IMG"
-    }
+    "driver": "null-co",
+    "node-name": "disk0"
   }
 }
 { "execute": "object-add",
@@ -181,12 +170,8 @@ run_qemu <<EOF
 { "execute": "qmp_capabilities" }
 { "execute": "blockdev-add",
   "arguments": {
-    "driver": "$IMGFMT",
-    "node-name": "disk0",
-    "file": {
-      "driver": "file",
-      "filename": "$TEST_IMG"
-    }
+    "driver": "null-co",
+    "node-name": "disk0"
   }
 }
 { "execute": "blockdev-add",
diff --git a/tests/qemu-iotests/184.out b/tests/qemu-iotests/184.out
index 4dc7984a85..672650cde8 100644
--- a/tests/qemu-iotests/184.out
+++ b/tests/qemu-iotests/184.out
@@ -1,5 +1,4 @@
 QA output created by 184
-Formatting 'TEST_DIR/t.IMGFMT', fmt=IMGFMT size=67108864
 
 == checking interface ==
 Testing:
@@ -28,12 +27,9 @@ Testing:
             "iops_rd": 0,
             "detect_zeroes": "off",
             "image": {
-                "virtual-size": 67108864,
-                "filename": "json:{\"throttle-group\": \"group0\", \"driver\": \"throttle\", \"file\": {\"driver\": \"qcow2\", \"file\": {\"driver\": \"file\", \"filename\": \"TEST_DIR/t.qcow2\"}}}",
-                "cluster-size": 65536,
-                "format": "throttle",
-                "actual-size": SIZE,
-                "dirty-flag": false
+                "virtual-size": 1073741824,
+                "filename": "json:{\"throttle-group\": \"group0\", \"driver\": \"throttle\", \"file\": {\"driver\": \"null-co\"}}",
+                "format": "throttle"
             },
             "iops_wr": 0,
             "ro": false,
@@ -51,34 +47,22 @@ Testing:
                 "direct": false,
                 "writeback": true
             },
-            "file": "json:{\"throttle-group\": \"group0\", \"driver\": \"throttle\", \"file\": {\"driver\": \"qcow2\", \"file\": {\"driver\": \"file\", \"filename\": \"TEST_DIR/t.qcow2\"}}}",
+            "file": "json:{\"throttle-group\": \"group0\", \"driver\": \"throttle\", \"file\": {\"driver\": \"null-co\"}}",
             "encryption_key_missing": false
         },
         {
             "iops_rd": 0,
             "detect_zeroes": "off",
             "image": {
-                "virtual-size": 67108864,
-                "filename": "TEST_DIR/t.qcow2",
-                "cluster-size": 65536,
-                "format": "qcow2",
-                "actual-size": SIZE,
-                "format-specific": {
-                    "type": "qcow2",
-                    "data": {
-                        "compat": "1.1",
-                        "lazy-refcounts": false,
-                        "refcount-bits": 16,
-                        "corrupt": false
-                    }
-                },
-                "dirty-flag": false
+                "virtual-size": 1073741824,
+                "filename": "null-co://",
+                "format": "null-co"
             },
             "iops_wr": 0,
             "ro": false,
             "node-name": "disk0",
             "backing_file_depth": 0,
-            "drv": "qcow2",
+            "drv": "null-co",
             "iops": 0,
             "bps_wr": 0,
             "write_threshold": 0,
@@ -90,36 +74,7 @@ Testing:
                 "direct": false,
                 "writeback": true
             },
-            "file": "TEST_DIR/t.qcow2",
-            "encryption_key_missing": false
-        },
-        {
-            "iops_rd": 0,
-            "detect_zeroes": "off",
-            "image": {
-                "virtual-size": 197120,
-                "filename": "TEST_DIR/t.qcow2",
-                "format": "file",
-                "actual-size": SIZE,
-                "dirty-flag": false
-            },
-            "iops_wr": 0,
-            "ro": false,
-            "node-name": "NODE_NAME",
-            "backing_file_depth": 0,
-            "drv": "file",
-            "iops": 0,
-            "bps_wr": 0,
-            "write_threshold": 0,
-            "encrypted": false,
-            "bps": 0,
-            "bps_rd": 0,
-            "cache": {
-                "no-flush": false,
-                "direct": false,
-                "writeback": true
-            },
-            "file": "TEST_DIR/t.qcow2",
+            "file": "null-co://",
             "encryption_key_missing": false
         }
     ]