iotests: add script_initialize

Like script_main, but doesn't require a single point of entry.
Replace all existing initialization sections with this drop-in replacement.

This brings debug support to all existing script-style iotests.

Signed-off-by: John Snow <jsnow@redhat.com>
Reviewed-by: Max Reitz <mreitz@redhat.com>
Message-Id: <20200331000014.11581-12-jsnow@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
[mreitz: Give 274 the same treatment]
Signed-off-by: Max Reitz <mreitz@redhat.com>
diff --git a/tests/qemu-iotests/149 b/tests/qemu-iotests/149
index b4a21bf..852768f 100755
--- a/tests/qemu-iotests/149
+++ b/tests/qemu-iotests/149
@@ -382,8 +382,7 @@
 
 
 # Obviously we only work with the luks image format
-iotests.verify_image_format(supported_fmts=['luks'])
-iotests.verify_platform()
+iotests.script_initialize(supported_fmts=['luks'])
 
 # We need sudo in order to run cryptsetup to create
 # dm-crypt devices. This is safe to use on any
diff --git a/tests/qemu-iotests/194 b/tests/qemu-iotests/194
index 9dc1bd3..8b1f720 100755
--- a/tests/qemu-iotests/194
+++ b/tests/qemu-iotests/194
@@ -21,8 +21,8 @@
 
 import iotests
 
-iotests.verify_image_format(supported_fmts=['qcow2', 'qed', 'raw'])
-iotests.verify_platform(['linux'])
+iotests.script_initialize(supported_fmts=['qcow2', 'qed', 'raw'],
+                          supported_platforms=['linux'])
 
 with iotests.FilePath('source.img') as source_img_path, \
      iotests.FilePath('dest.img') as dest_img_path, \
diff --git a/tests/qemu-iotests/202 b/tests/qemu-iotests/202
index 920a868..e3900a4 100755
--- a/tests/qemu-iotests/202
+++ b/tests/qemu-iotests/202
@@ -24,8 +24,8 @@
 
 import iotests
 
-iotests.verify_image_format(supported_fmts=['qcow2'])
-iotests.verify_platform(['linux'])
+iotests.script_initialize(supported_fmts=['qcow2'],
+                          supported_platforms=['linux'])
 
 with iotests.FilePath('disk0.img') as disk0_img_path, \
      iotests.FilePath('disk1.img') as disk1_img_path, \
diff --git a/tests/qemu-iotests/203 b/tests/qemu-iotests/203
index 49eff5d..4b4bd33 100755
--- a/tests/qemu-iotests/203
+++ b/tests/qemu-iotests/203
@@ -24,8 +24,8 @@
 
 import iotests
 
-iotests.verify_image_format(supported_fmts=['qcow2'])
-iotests.verify_platform(['linux'])
+iotests.script_initialize(supported_fmts=['qcow2'],
+                          supported_platforms=['linux'])
 
 with iotests.FilePath('disk0.img') as disk0_img_path, \
      iotests.FilePath('disk1.img') as disk1_img_path, \
diff --git a/tests/qemu-iotests/206 b/tests/qemu-iotests/206
index e2b50ae2..f42432a 100755
--- a/tests/qemu-iotests/206
+++ b/tests/qemu-iotests/206
@@ -23,7 +23,7 @@
 import iotests
 from iotests import imgfmt
 
-iotests.verify_image_format(supported_fmts=['qcow2'])
+iotests.script_initialize(supported_fmts=['qcow2'])
 
 with iotests.FilePath('t.qcow2') as disk_path, \
      iotests.FilePath('t.qcow2.base') as backing_path, \
diff --git a/tests/qemu-iotests/207 b/tests/qemu-iotests/207
index 3d9c120..a662141 100755
--- a/tests/qemu-iotests/207
+++ b/tests/qemu-iotests/207
@@ -24,8 +24,10 @@
 import subprocess
 import re
 
-iotests.verify_image_format(supported_fmts=['raw'])
-iotests.verify_protocol(supported=['ssh'])
+iotests.script_initialize(
+    supported_fmts=['raw'],
+    supported_protocols=['ssh'],
+)
 
 def filter_hash(qmsg):
     def _filter(key, value):
diff --git a/tests/qemu-iotests/208 b/tests/qemu-iotests/208
index 1c3fc8c..6cb642f 100755
--- a/tests/qemu-iotests/208
+++ b/tests/qemu-iotests/208
@@ -22,7 +22,7 @@
 
 import iotests
 
-iotests.verify_image_format(supported_fmts=['generic'])
+iotests.script_initialize(supported_fmts=['generic'])
 
 with iotests.FilePath('disk.img') as disk_img_path, \
      iotests.FilePath('disk-snapshot.img') as disk_snapshot_img_path, \
diff --git a/tests/qemu-iotests/209 b/tests/qemu-iotests/209
index 65c1a1e..8c804f4 100755
--- a/tests/qemu-iotests/209
+++ b/tests/qemu-iotests/209
@@ -22,7 +22,7 @@
 from iotests import qemu_img_create, qemu_io, qemu_img_verbose, qemu_nbd, \
                     file_path
 
-iotests.verify_image_format(supported_fmts=['qcow2'])
+iotests.script_initialize(supported_fmts=['qcow2'])
 
 disk = file_path('disk')
 nbd_sock = file_path('nbd-sock', base_dir=iotests.sock_dir)
diff --git a/tests/qemu-iotests/210 b/tests/qemu-iotests/210
index e49896e..7bf591f 100755
--- a/tests/qemu-iotests/210
+++ b/tests/qemu-iotests/210
@@ -23,8 +23,10 @@
 import iotests
 from iotests import imgfmt
 
-iotests.verify_image_format(supported_fmts=['luks'])
-iotests.verify_protocol(supported=['file'])
+iotests.script_initialize(
+    supported_fmts=['luks'],
+    supported_protocols=['file'],
+)
 
 with iotests.FilePath('t.luks') as disk_path, \
      iotests.VM() as vm:
diff --git a/tests/qemu-iotests/211 b/tests/qemu-iotests/211
index 163994d..4969edb 100755
--- a/tests/qemu-iotests/211
+++ b/tests/qemu-iotests/211
@@ -23,8 +23,10 @@
 import iotests
 from iotests import imgfmt
 
-iotests.verify_image_format(supported_fmts=['vdi'])
-iotests.verify_protocol(supported=['file'])
+iotests.script_initialize(
+    supported_fmts=['vdi'],
+    supported_protocols=['file'],
+)
 
 def blockdev_create(vm, options):
     error = vm.blockdev_create(options)
diff --git a/tests/qemu-iotests/212 b/tests/qemu-iotests/212
index 800f92d..45d0884 100755
--- a/tests/qemu-iotests/212
+++ b/tests/qemu-iotests/212
@@ -23,8 +23,10 @@
 import iotests
 from iotests import imgfmt
 
-iotests.verify_image_format(supported_fmts=['parallels'])
-iotests.verify_protocol(supported=['file'])
+iotests.script_initialize(
+    supported_fmts=['parallels'],
+    supported_protocols=['file'],
+)
 
 with iotests.FilePath('t.parallels') as disk_path, \
      iotests.VM() as vm:
diff --git a/tests/qemu-iotests/213 b/tests/qemu-iotests/213
index 1eee452..cf638eb 100755
--- a/tests/qemu-iotests/213
+++ b/tests/qemu-iotests/213
@@ -23,8 +23,10 @@
 import iotests
 from iotests import imgfmt
 
-iotests.verify_image_format(supported_fmts=['vhdx'])
-iotests.verify_protocol(supported=['file'])
+iotests.script_initialize(
+    supported_fmts=['vhdx'],
+    supported_protocols=['file'],
+)
 
 with iotests.FilePath('t.vhdx') as disk_path, \
      iotests.VM() as vm:
diff --git a/tests/qemu-iotests/216 b/tests/qemu-iotests/216
index 372f042..de11d85 100755
--- a/tests/qemu-iotests/216
+++ b/tests/qemu-iotests/216
@@ -23,8 +23,8 @@
 from iotests import log, qemu_img, qemu_io_silent
 
 # Need backing file support
-iotests.verify_image_format(supported_fmts=['qcow2', 'qcow', 'qed', 'vmdk'])
-iotests.verify_platform(['linux'])
+iotests.script_initialize(supported_fmts=['qcow2', 'qcow', 'qed', 'vmdk'],
+                          supported_platforms=['linux'])
 
 log('')
 log('=== Copy-on-read across nodes ===')
diff --git a/tests/qemu-iotests/218 b/tests/qemu-iotests/218
index 1325ba9..5586870 100755
--- a/tests/qemu-iotests/218
+++ b/tests/qemu-iotests/218
@@ -29,7 +29,7 @@
 import iotests
 from iotests import log, qemu_img, qemu_io_silent
 
-iotests.verify_image_format(supported_fmts=['qcow2', 'raw'])
+iotests.script_initialize(supported_fmts=['qcow2', 'raw'])
 
 
 # Launches the VM, adds two null-co nodes (source and target), and
diff --git a/tests/qemu-iotests/219 b/tests/qemu-iotests/219
index b877477..db272c5 100755
--- a/tests/qemu-iotests/219
+++ b/tests/qemu-iotests/219
@@ -21,7 +21,7 @@
 
 import iotests
 
-iotests.verify_image_format(supported_fmts=['qcow2'])
+iotests.script_initialize(supported_fmts=['qcow2'])
 
 img_size = 4 * 1024 * 1024
 
diff --git a/tests/qemu-iotests/222 b/tests/qemu-iotests/222
index bf1718e..6602f6b 100755
--- a/tests/qemu-iotests/222
+++ b/tests/qemu-iotests/222
@@ -24,9 +24,10 @@
 import iotests
 from iotests import log, qemu_img, qemu_io, qemu_io_silent
 
-iotests.verify_platform(['linux'])
-iotests.verify_image_format(supported_fmts=['qcow2', 'qcow', 'qed', 'vmdk',
-                                            'vhdx', 'raw'])
+iotests.script_initialize(
+    supported_fmts=['qcow2', 'qcow', 'qed', 'vmdk', 'vhdx', 'raw'],
+    supported_platforms=['linux'],
+)
 
 patterns = [("0x5d", "0",         "64k"),
             ("0xd5", "1M",        "64k"),
diff --git a/tests/qemu-iotests/224 b/tests/qemu-iotests/224
index e91fb26..81ca1e4 100755
--- a/tests/qemu-iotests/224
+++ b/tests/qemu-iotests/224
@@ -26,8 +26,8 @@
 import json
 
 # Need backing file support (for arbitrary backing formats)
-iotests.verify_image_format(supported_fmts=['qcow2', 'qcow', 'qed'])
-iotests.verify_platform(['linux'])
+iotests.script_initialize(supported_fmts=['qcow2', 'qcow', 'qed'],
+                          supported_platforms=['linux'])
 
 
 # There are two variations of this test:
diff --git a/tests/qemu-iotests/228 b/tests/qemu-iotests/228
index 64bc82e..da0900f 100755
--- a/tests/qemu-iotests/228
+++ b/tests/qemu-iotests/228
@@ -25,8 +25,10 @@
         filter_qmp_testfiles, filter_qmp_imgfmt
 
 # Need backing file and change-backing-file support
-iotests.verify_image_format(supported_fmts=['qcow2', 'qed'])
-iotests.verify_platform(['linux'])
+iotests.script_initialize(
+    supported_fmts=['qcow2', 'qed'],
+    supported_platforms=['linux'],
+)
 
 
 def log_node_info(node):
diff --git a/tests/qemu-iotests/234 b/tests/qemu-iotests/234
index 324c154..73c899d 100755
--- a/tests/qemu-iotests/234
+++ b/tests/qemu-iotests/234
@@ -23,8 +23,8 @@
 import iotests
 import os
 
-iotests.verify_image_format(supported_fmts=['qcow2'])
-iotests.verify_platform(['linux'])
+iotests.script_initialize(supported_fmts=['qcow2'],
+                          supported_platforms=['linux'])
 
 with iotests.FilePath('img') as img_path, \
      iotests.FilePath('backing') as backing_path, \
diff --git a/tests/qemu-iotests/235 b/tests/qemu-iotests/235
index 7608261..d1b10ac 100755
--- a/tests/qemu-iotests/235
+++ b/tests/qemu-iotests/235
@@ -27,6 +27,8 @@
 
 from qemu.machine import QEMUMachine
 
+iotests.script_initialize(supported_fmts=['qcow2'])
+
 # Note:
 # This test was added to check that mirror dead-lock was fixed (see previous
 # commit before this test addition).
@@ -40,8 +42,6 @@
 
 size = 1 * 1024 * 1024 * 1024
 
-iotests.verify_image_format(supported_fmts=['qcow2'])
-
 disk = file_path('disk')
 
 # prepare source image
diff --git a/tests/qemu-iotests/236 b/tests/qemu-iotests/236
index 8ce927a..6f5cee2 100755
--- a/tests/qemu-iotests/236
+++ b/tests/qemu-iotests/236
@@ -22,7 +22,7 @@
 import iotests
 from iotests import log
 
-iotests.verify_image_format(supported_fmts=['generic'])
+iotests.script_initialize(supported_fmts=['generic'])
 size = 64 * 1024 * 1024
 granularity = 64 * 1024
 
diff --git a/tests/qemu-iotests/237 b/tests/qemu-iotests/237
index 50ba364..5b21ad3 100755
--- a/tests/qemu-iotests/237
+++ b/tests/qemu-iotests/237
@@ -24,7 +24,7 @@
 import iotests
 from iotests import imgfmt
 
-iotests.verify_image_format(supported_fmts=['vmdk'])
+iotests.script_initialize(supported_fmts=['vmdk'])
 
 with iotests.FilePath('t.vmdk') as disk_path, \
      iotests.FilePath('t.vmdk.1') as extent1_path, \
diff --git a/tests/qemu-iotests/238 b/tests/qemu-iotests/238
index d4e0602..b8fcf15 100755
--- a/tests/qemu-iotests/238
+++ b/tests/qemu-iotests/238
@@ -23,6 +23,8 @@
 import iotests
 from iotests import log
 
+iotests.script_initialize()
+
 virtio_scsi_device = iotests.get_virtio_scsi_device()
 
 vm = iotests.VM()
diff --git a/tests/qemu-iotests/242 b/tests/qemu-iotests/242
index 9761787..64f1bd9 100755
--- a/tests/qemu-iotests/242
+++ b/tests/qemu-iotests/242
@@ -24,7 +24,7 @@
 from iotests import qemu_img_create, qemu_io, qemu_img_pipe, \
     file_path, img_info_log, log, filter_qemu_io
 
-iotests.verify_image_format(supported_fmts=['qcow2'])
+iotests.script_initialize(supported_fmts=['qcow2'])
 
 disk = file_path('disk')
 chunk = 256 * 1024
diff --git a/tests/qemu-iotests/246 b/tests/qemu-iotests/246
index 59a216a..58a479c 100755
--- a/tests/qemu-iotests/246
+++ b/tests/qemu-iotests/246
@@ -22,7 +22,7 @@
 import iotests
 from iotests import log
 
-iotests.verify_image_format(supported_fmts=['qcow2'])
+iotests.script_initialize(supported_fmts=['qcow2'])
 size = 64 * 1024 * 1024 * 1024
 gran_small = 32 * 1024
 gran_large = 128 * 1024
diff --git a/tests/qemu-iotests/248 b/tests/qemu-iotests/248
index 68c3746..18ba034 100755
--- a/tests/qemu-iotests/248
+++ b/tests/qemu-iotests/248
@@ -21,7 +21,7 @@
 import iotests
 from iotests import qemu_img_create, qemu_io, file_path, filter_qmp_testfiles
 
-iotests.verify_image_format(supported_fmts=['qcow2'])
+iotests.script_initialize(supported_fmts=['qcow2'])
 
 source, target = file_path('source', 'target')
 size = 5 * 1024 * 1024
diff --git a/tests/qemu-iotests/254 b/tests/qemu-iotests/254
index ee66c98..150e58b 100755
--- a/tests/qemu-iotests/254
+++ b/tests/qemu-iotests/254
@@ -21,7 +21,7 @@
 import iotests
 from iotests import qemu_img_create, file_path, log
 
-iotests.verify_image_format(supported_fmts=['qcow2'])
+iotests.script_initialize(supported_fmts=['qcow2'])
 
 disk, top = file_path('disk', 'top')
 size = 1024 * 1024
diff --git a/tests/qemu-iotests/255 b/tests/qemu-iotests/255
index 4a4818b..8f08f74 100755
--- a/tests/qemu-iotests/255
+++ b/tests/qemu-iotests/255
@@ -23,7 +23,7 @@
 import iotests
 from iotests import imgfmt
 
-iotests.verify_image_format(supported_fmts=['qcow2'])
+iotests.script_initialize(supported_fmts=['qcow2'])
 
 iotests.log('Finishing a commit job with background reads')
 iotests.log('============================================')
diff --git a/tests/qemu-iotests/256 b/tests/qemu-iotests/256
index e34074c..db8d6f3 100755
--- a/tests/qemu-iotests/256
+++ b/tests/qemu-iotests/256
@@ -23,7 +23,7 @@
 import iotests
 from iotests import log
 
-iotests.verify_image_format(supported_fmts=['qcow2'])
+iotests.script_initialize(supported_fmts=['qcow2'])
 size = 64 * 1024 * 1024
 
 with iotests.FilePath('img0') as img0_path, \
diff --git a/tests/qemu-iotests/258 b/tests/qemu-iotests/258
index 091755a..a65151d 100755
--- a/tests/qemu-iotests/258
+++ b/tests/qemu-iotests/258
@@ -24,9 +24,10 @@
         filter_qmp_testfiles, filter_qmp_imgfmt
 
 # Need backing file and change-backing-file support
-iotests.verify_image_format(supported_fmts=['qcow2', 'qed'])
-iotests.verify_platform(['linux'])
-
+iotests.script_initialize(
+    supported_fmts=['qcow2', 'qed'],
+    supported_platforms=['linux'],
+)
 
 # Returns a node for blockdev-add
 def node(node_name, path, backing=None, fmt=None, throttle=None):
diff --git a/tests/qemu-iotests/260 b/tests/qemu-iotests/260
index 30c0de3..804a7ad 100755
--- a/tests/qemu-iotests/260
+++ b/tests/qemu-iotests/260
@@ -21,7 +21,9 @@
 import iotests
 from iotests import qemu_img_create, file_path, log, filter_qmp_event
 
-iotests.verify_image_format(supported_fmts=['qcow2'])
+iotests.script_initialize(
+    supported_fmts=['qcow2']
+)
 
 base, top = file_path('base', 'top')
 size = 64 * 1024 * 3
diff --git a/tests/qemu-iotests/262 b/tests/qemu-iotests/262
index 8835dce..03af061 100755
--- a/tests/qemu-iotests/262
+++ b/tests/qemu-iotests/262
@@ -23,8 +23,8 @@
 import iotests
 import os
 
-iotests.verify_image_format(supported_fmts=['qcow2'])
-iotests.verify_platform(['linux'])
+iotests.script_initialize(supported_fmts=['qcow2'],
+                          supported_platforms=['linux'])
 
 with iotests.FilePath('img') as img_path, \
      iotests.FilePath('mig_fifo') as fifo, \
diff --git a/tests/qemu-iotests/264 b/tests/qemu-iotests/264
index 879123a..304a744 100755
--- a/tests/qemu-iotests/264
+++ b/tests/qemu-iotests/264
@@ -24,7 +24,9 @@
 from iotests import qemu_img_create, qemu_io_silent_check, file_path, \
         qemu_nbd_popen, log
 
-iotests.verify_image_format(supported_fmts=['qcow2'])
+iotests.script_initialize(
+    supported_fmts=['qcow2'],
+)
 
 disk_a, disk_b, nbd_sock = file_path('disk_a', 'disk_b', 'nbd-sock')
 nbd_uri = 'nbd+unix:///?socket=' + nbd_sock
diff --git a/tests/qemu-iotests/274 b/tests/qemu-iotests/274
index e951f72..5d1bf34 100755
--- a/tests/qemu-iotests/274
+++ b/tests/qemu-iotests/274
@@ -21,8 +21,8 @@
 
 import iotests
 
-iotests.verify_image_format(supported_fmts=['qcow2'])
-iotests.verify_platform(['linux'])
+iotests.script_initialize(supported_fmts=['qcow2'],
+                          supported_platforms=['linux'])
 
 size_short = 1 * 1024 * 1024
 size_long = 2 * 1024 * 1024
diff --git a/tests/qemu-iotests/277 b/tests/qemu-iotests/277
index 04aa15a..d34f870 100755
--- a/tests/qemu-iotests/277
+++ b/tests/qemu-iotests/277
@@ -23,6 +23,8 @@
 import iotests
 from iotests import file_path, log
 
+iotests.script_initialize()
+
 
 nbd_sock, conf_file = file_path('nbd-sock', 'nbd-fault-injector.conf')
 
diff --git a/tests/qemu-iotests/280 b/tests/qemu-iotests/280
index 69288fd..f594bb9 100755
--- a/tests/qemu-iotests/280
+++ b/tests/qemu-iotests/280
@@ -22,9 +22,11 @@
 import iotests
 import os
 
-iotests.verify_image_format(supported_fmts=['qcow2'])
-iotests.verify_protocol(supported=['file'])
-iotests.verify_platform(['linux'])
+iotests.script_initialize(
+    supported_fmts=['qcow2'],
+    supported_protocols=['file'],
+    supported_platforms=['linux'],
+)
 
 with iotests.FilePath('base') as base_path , \
      iotests.FilePath('top') as top_path, \
diff --git a/tests/qemu-iotests/283 b/tests/qemu-iotests/283
index 55b7cff..e17b953 100644
--- a/tests/qemu-iotests/283
+++ b/tests/qemu-iotests/283
@@ -21,7 +21,9 @@
 import iotests
 
 # The test is unrelated to formats, restrict it to qcow2 to avoid extra runs
-iotests.verify_image_format(supported_fmts=['qcow2'])
+iotests.script_initialize(
+    supported_fmts=['qcow2'],
+)
 
 size = 1024 * 1024
 
diff --git a/tests/qemu-iotests/iotests.py b/tests/qemu-iotests/iotests.py
index cf10c42..9f85e1f 100644
--- a/tests/qemu-iotests/iotests.py
+++ b/tests/qemu-iotests/iotests.py
@@ -28,7 +28,8 @@
 import struct
 import subprocess
 import sys
-from typing import (Any, Callable, Dict, Iterable, List, Optional, TypeVar)
+from typing import (Any, Callable, Dict, Iterable,
+                    List, Optional, Sequence, TypeVar)
 import unittest
 
 # pylint: disable=import-error, wrong-import-position
@@ -1029,12 +1030,11 @@
     if not_sup or (imgproto in unsupported):
         notrun('not suitable for this protocol: %s' % imgproto)
 
-def verify_platform(supported=None, unsupported=None):
-    if unsupported is not None:
-        if any((sys.platform.startswith(x) for x in unsupported)):
-            notrun('not suitable for this OS: %s' % sys.platform)
+def verify_platform(supported=(), unsupported=()):
+    if any((sys.platform.startswith(x) for x in unsupported)):
+        notrun('not suitable for this OS: %s' % sys.platform)
 
-    if supported is not None:
+    if supported:
         if not any((sys.platform.startswith(x) for x in supported)):
             notrun('not suitable for this OS: %s' % sys.platform)
 
@@ -1116,7 +1116,18 @@
             return func(*args, **kwargs)
     return func_wrapper
 
-def execute_unittest(output, verbosity, debug):
+def execute_unittest(debug=False):
+    """Executes unittests within the calling module."""
+
+    verbosity = 2 if debug else 1
+
+    if debug:
+        output = sys.stdout
+    else:
+        # We need to filter out the time taken from the output so that
+        # qemu-iotest can reliably diff the results against master output.
+        output = io.StringIO()
+
     runner = unittest.TextTestRunner(stream=output, descriptions=True,
                                      verbosity=verbosity)
     try:
@@ -1124,6 +1135,8 @@
         # exception
         unittest.main(testRunner=runner)
     finally:
+        # We need to filter out the time taken from the output so that
+        # qemu-iotest can reliably diff the results against master output.
         if not debug:
             out = output.getvalue()
             out = re.sub(r'Ran (\d+) tests? in [\d.]+s', r'Ran \1 tests', out)
@@ -1135,13 +1148,19 @@
 
             sys.stderr.write(out)
 
-def execute_test(test_function=None,
-                 supported_fmts=(),
-                 supported_platforms=None,
-                 supported_cache_modes=(), supported_aio_modes=(),
-                 unsupported_fmts=(), supported_protocols=(),
-                 unsupported_protocols=()):
-    """Run either unittest or script-style tests."""
+def execute_setup_common(supported_fmts: Sequence[str] = (),
+                         supported_platforms: Sequence[str] = (),
+                         supported_cache_modes: Sequence[str] = (),
+                         supported_aio_modes: Sequence[str] = (),
+                         unsupported_fmts: Sequence[str] = (),
+                         supported_protocols: Sequence[str] = (),
+                         unsupported_protocols: Sequence[str] = ()) -> bool:
+    """
+    Perform necessary setup for either script-style or unittest-style tests.
+
+    :return: Bool; Whether or not debug mode has been requested via the CLI.
+    """
+    # Note: Python 3.6 and pylint do not like 'Collection' so use 'Sequence'.
 
     # We are using TEST_DIR and QEMU_DEFAULT_MACHINE as proxies to
     # indicate that we're not being run via "check". There may be
@@ -1151,34 +1170,39 @@
         sys.stderr.write('Please run this test via the "check" script\n')
         sys.exit(os.EX_USAGE)
 
-    debug = '-d' in sys.argv
-    verbosity = 1
     verify_image_format(supported_fmts, unsupported_fmts)
     verify_protocol(supported_protocols, unsupported_protocols)
     verify_platform(supported=supported_platforms)
     verify_cache_mode(supported_cache_modes)
     verify_aio_mode(supported_aio_modes)
 
+    debug = '-d' in sys.argv
     if debug:
-        output = sys.stdout
-        verbosity = 2
         sys.argv.remove('-d')
-    else:
-        # We need to filter out the time taken from the output so that
-        # qemu-iotest can reliably diff the results against master output.
-        output = io.StringIO()
-
     logging.basicConfig(level=(logging.DEBUG if debug else logging.WARN))
 
+    return debug
+
+def execute_test(*args, test_function=None, **kwargs):
+    """Run either unittest or script-style tests."""
+
+    debug = execute_setup_common(*args, **kwargs)
     if not test_function:
-        execute_unittest(output, verbosity, debug)
+        execute_unittest(debug)
     else:
         test_function()
 
+# This is called from script-style iotests without a single point of entry
+def script_initialize(*args, **kwargs):
+    """Initialize script-style tests without running any tests."""
+    execute_setup_common(*args, **kwargs)
+
+# This is called from script-style iotests with a single point of entry
 def script_main(test_function, *args, **kwargs):
     """Run script-style tests outside of the unittest framework"""
-    execute_test(test_function, *args, **kwargs)
+    execute_test(*args, test_function=test_function, **kwargs)
 
+# This is called from unittest style iotests
 def main(*args, **kwargs):
     """Run tests using the unittest framework"""
-    execute_test(None, *args, **kwargs)
+    execute_test(*args, **kwargs)