Merge remote-tracking branch 'remotes/kevin/tags/for-upstream' into staging

Block layer patches:

- Fix crash on write to read-only devices
- iotests: Rewrite 'check' in Python, get rid of 'groups' and allow
  non-numeric test case names

# gpg: Signature made Wed 27 Jan 2021 19:56:00 GMT
# gpg:                using RSA key DC3DEB159A9AF95D3D7456FE7F09B272C88F2FD6
# gpg:                issuer "kwolf@redhat.com"
# gpg: Good signature from "Kevin Wolf <kwolf@redhat.com>" [full]
# Primary key fingerprint: DC3D EB15 9A9A F95D 3D74  56FE 7F09 B272 C88F 2FD6

* remotes/kevin/tags/for-upstream:
  iotests: rename and move 169 and 199 tests
  iotests: rewrite check into python
  iotests: add testrunner.py
  iotests: add testenv.py
  iotests: add findtests.py
  iotests: 146: drop extra whitespaces from .out file
  virtio-scsi-test: Test writing to scsi-cd device
  block: Separate blk_is_writable() and blk_supports_write_perm()

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

docs/devel/testing.rst

@@ -111,7 +111,7 @@ check-block
 -----------
 
 ``make check-block`` runs a subset of the block layer iotests (the tests that
-are in the "auto" group in ``tests/qemu-iotests/group``).
+are in the "auto" group).
 See the "QEMU iotests" section below for more information.
 
 GCC gcov support
@@ -224,6 +224,54 @@ another application on the host may have locked the file, possibly leading to a
 test failure.  If using such devices are explicitly desired, consider adding
 ``locking=off`` option to disable image locking.
 
+Test case groups
+----------------
+
+"Tests may belong to one or more test groups, which are defined in the form
+of a comment in the test source file. By convention, test groups are listed
+in the second line of the test file, after the "#!/..." line, like this:
+
+.. code::
+
+  #!/usr/bin/env python3
+  # group: auto quick
+  #
+  ...
+
+Another way of defining groups is creating the tests/qemu-iotests/group.local
+file. This should be used only for downstream (this file should never appear
+in upstream). This file may be used for defining some downstream test groups
+or for temporarily disabling tests, like this:
+
+.. code::
+
+  # groups for some company downstream process
+  #
+  # ci - tests to run on build
+  # down - our downstream tests, not for upstream
+  #
+  # Format of each line is:
+  # TEST_NAME TEST_GROUP [TEST_GROUP ]...
+
+  013 ci
+  210 disabled
+  215 disabled
+  our-ugly-workaround-test down ci
+
+Note that the following group names have a special meaning:
+
+- quick: Tests in this group should finish within a few seconds.
+
+- auto: Tests in this group are used during "make check" and should be
+  runnable in any case. That means they should run with every QEMU binary
+  (also non-x86), with every QEMU configuration (i.e. must not fail if
+  an optional feature is not compiled in - but reporting a "skip" is ok),
+  work at least with the qcow2 file format, work with all kind of host
+  filesystems and users (e.g. "nobody" or "root") and must not take too
+  much memory and disk space (since CI pipelines tend to fail otherwise).
+
+- disabled: Tests in this group are disabled and ignored by check.
+
 .. _docker-ref:
 
 Docker based tests