diff --git a/tests/qemu-iotests/030 b/tests/qemu-iotests/030
index 1f55095..ae56f3b 100755
--- a/tests/qemu-iotests/030
+++ b/tests/qemu-iotests/030
@@ -22,30 +22,16 @@
 import os
 import iotests
 from iotests import qemu_img, qemu_io
-import struct
 
 backing_img = os.path.join(iotests.test_dir, 'backing.img')
 mid_img = os.path.join(iotests.test_dir, 'mid.img')
 test_img = os.path.join(iotests.test_dir, 'test.img')
 
-class ImageStreamingTestCase(iotests.QMPTestCase):
-    '''Abstract base class for image streaming test cases'''
-
-    def create_image(self, name, size):
-        file = open(name, 'w')
-        i = 0
-        while i < size:
-            sector = struct.pack('>l504xl', i / 512, i / 512)
-            file.write(sector)
-            i = i + 512
-        file.close()
-
-
-class TestSingleDrive(ImageStreamingTestCase):
+class TestSingleDrive(iotests.QMPTestCase):
     image_len = 1 * 1024 * 1024 # MB
 
     def setUp(self):
-        self.create_image(backing_img, TestSingleDrive.image_len)
+        iotests.create_image(backing_img, TestSingleDrive.image_len)
         qemu_img('create', '-f', iotests.imgfmt, '-o', 'backing_file=%s' % backing_img, mid_img)
         qemu_img('create', '-f', iotests.imgfmt, '-o', 'backing_file=%s' % mid_img, test_img)
         self.vm = iotests.VM().add_drive(test_img)
@@ -145,12 +131,12 @@
         self.assert_qmp(result, 'error/class', 'DeviceNotFound')
 
 
-class TestSmallerBackingFile(ImageStreamingTestCase):
+class TestSmallerBackingFile(iotests.QMPTestCase):
     backing_len = 1 * 1024 * 1024 # MB
     image_len = 2 * backing_len
 
     def setUp(self):
-        self.create_image(backing_img, self.backing_len)
+        iotests.create_image(backing_img, self.backing_len)
         qemu_img('create', '-f', iotests.imgfmt, '-o', 'backing_file=%s' % backing_img, test_img, str(self.image_len))
         self.vm = iotests.VM().add_drive(test_img)
         self.vm.launch()
@@ -176,7 +162,7 @@
         self.assert_no_active_block_jobs()
         self.vm.shutdown()
 
-class TestErrors(ImageStreamingTestCase):
+class TestErrors(iotests.QMPTestCase):
     image_len = 2 * 1024 * 1024 # MB
 
     # this should match STREAM_BUFFER_SIZE/512 in block/stream.c
@@ -208,7 +194,7 @@
 class TestEIO(TestErrors):
     def setUp(self):
         self.blkdebug_file = backing_img + ".blkdebug"
-        self.create_image(backing_img, TestErrors.image_len)
+        iotests.create_image(backing_img, TestErrors.image_len)
         self.create_blkdebug_file(self.blkdebug_file, "read_aio", 5)
         qemu_img('create', '-f', iotests.imgfmt,
                  '-o', 'backing_file=blkdebug:%s:%s,backing_fmt=raw'
@@ -344,7 +330,7 @@
 class TestENOSPC(TestErrors):
     def setUp(self):
         self.blkdebug_file = backing_img + ".blkdebug"
-        self.create_image(backing_img, TestErrors.image_len)
+        iotests.create_image(backing_img, TestErrors.image_len)
         self.create_blkdebug_file(self.blkdebug_file, "read_aio", 28)
         qemu_img('create', '-f', iotests.imgfmt,
                  '-o', 'backing_file=blkdebug:%s:%s,backing_fmt=raw'
@@ -397,7 +383,7 @@
         self.assert_no_active_block_jobs()
         self.vm.shutdown()
 
-class TestStreamStop(ImageStreamingTestCase):
+class TestStreamStop(iotests.QMPTestCase):
     image_len = 8 * 1024 * 1024 * 1024 # GB
 
     def setUp(self):
@@ -423,7 +409,7 @@
 
         self.cancel_and_wait()
 
-class TestSetSpeed(ImageStreamingTestCase):
+class TestSetSpeed(iotests.QMPTestCase):
     image_len = 80 * 1024 * 1024 # MB
 
     def setUp(self):
diff --git a/tests/qemu-iotests/041 b/tests/qemu-iotests/041
index 7702074..1e923e7 100755
--- a/tests/qemu-iotests/041
+++ b/tests/qemu-iotests/041
@@ -22,7 +22,6 @@
 import os
 import iotests
 from iotests import qemu_img, qemu_io
-import struct
 
 backing_img = os.path.join(iotests.test_dir, 'backing.img')
 target_backing_img = os.path.join(iotests.test_dir, 'target-backing.img')
@@ -71,20 +70,11 @@
 
         self.assert_no_active_block_jobs()
 
-    def create_image(self, name, size):
-        file = open(name, 'w')
-        i = 0
-        while i < size:
-            sector = struct.pack('>l504xl', i / 512, i / 512)
-            file.write(sector)
-            i = i + 512
-        file.close()
-
 class TestSingleDrive(ImageMirroringTestCase):
     image_len = 1 * 1024 * 1024 # MB
 
     def setUp(self):
-        self.create_image(backing_img, TestSingleDrive.image_len)
+        iotests.create_image(backing_img, TestSingleDrive.image_len)
         qemu_img('create', '-f', iotests.imgfmt, '-o', 'backing_file=%s' % backing_img, test_img)
         self.vm = iotests.VM().add_drive(test_img)
         self.vm.launch()
@@ -230,15 +220,15 @@
     image_len = 2 * 1024 * 1024 # MB
 
     def complete_and_wait(self, drive='drive0', wait_ready=True):
-        self.create_image(target_backing_img, TestMirrorNoBacking.image_len)
+        iotests.create_image(target_backing_img, TestMirrorNoBacking.image_len)
         return ImageMirroringTestCase.complete_and_wait(self, drive, wait_ready)
 
     def compare_images(self, img1, img2):
-        self.create_image(target_backing_img, TestMirrorNoBacking.image_len)
+        iotests.create_image(target_backing_img, TestMirrorNoBacking.image_len)
         return iotests.compare_images(img1, img2)
 
     def setUp(self):
-        self.create_image(backing_img, TestMirrorNoBacking.image_len)
+        iotests.create_image(backing_img, TestMirrorNoBacking.image_len)
         qemu_img('create', '-f', iotests.imgfmt, '-o', 'backing_file=%s' % backing_img, test_img)
         self.vm = iotests.VM().add_drive(test_img)
         self.vm.launch()
@@ -306,7 +296,7 @@
     image_len = 2 * 1024 * 1024 # MB
 
     def setUp(self):
-        self.create_image(backing_img, TestMirrorResized.backing_len)
+        iotests.create_image(backing_img, TestMirrorResized.backing_len)
         qemu_img('create', '-f', iotests.imgfmt, '-o', 'backing_file=%s' % backing_img, test_img)
         qemu_img('resize', test_img, '2M')
         self.vm = iotests.VM().add_drive(test_img)
@@ -381,7 +371,7 @@
 
     def setUp(self):
         self.blkdebug_file = backing_img + ".blkdebug"
-        self.create_image(backing_img, TestReadErrors.image_len)
+        iotests.create_image(backing_img, TestReadErrors.image_len)
         self.create_blkdebug_file(self.blkdebug_file, "read_aio", 5)
         qemu_img('create', '-f', iotests.imgfmt,
                  '-o', 'backing_file=blkdebug:%s:%s,backing_fmt=raw'
@@ -536,7 +526,7 @@
 
     def setUp(self):
         self.blkdebug_file = target_img + ".blkdebug"
-        self.create_image(backing_img, TestWriteErrors.image_len)
+        iotests.create_image(backing_img, TestWriteErrors.image_len)
         self.create_blkdebug_file(self.blkdebug_file, "write_aio", 5)
         qemu_img('create', '-f', iotests.imgfmt, '-obacking_file=%s' %(backing_img), test_img)
         self.vm = iotests.VM().add_drive(test_img)
diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
index 733b82b..8a8f181 100644
--- a/tests/qemu-iotests/iotests.py
+++ b/tests/qemu-iotests/iotests.py
@@ -23,6 +23,7 @@
 import unittest
 import sys; sys.path.append(os.path.join(os.path.dirname(__file__), '..', '..', 'QMP'))
 import qmp
+import struct
 
 __all__ = ['imgfmt', 'imgproto', 'test_dir' 'qemu_img', 'qemu_io',
            'VM', 'QMPTestCase', 'notrun', 'main']
@@ -56,6 +57,16 @@
     return qemu_img('compare', '-f', imgfmt,
                     '-F', imgfmt, img1, img2) == 0
 
+def create_image(name, size):
+    '''Create a fully-allocated raw image with sector markers'''
+    file = open(name, 'w')
+    i = 0
+    while i < size:
+        sector = struct.pack('>l504xl', i / 512, i / 512)
+        file.write(sector)
+        i = i + 512
+    file.close()
+
 class VM(object):
     '''A QEMU VM'''