# Background
KUnit currently lacks any first-class support for mocking.
For an overview and discussion on the pros and cons, see
https://martinfowler.com/articles/mocksArentStubs.html
This patch set introduces the basic machinery needed for mocking:
setting and validating expectations, setting default actions, etc.
Using that basic infrastructure, we add macros for "class mocking", as
it's probably the easiest type of mocking to start with.
## Class mocking
By "class mocking", we're referring mocking out function pointers stored
in structs like:
struct sender {
int (*send)(struct sender *sender, int data);
};
After the necessary DEFINE_* macros, we can then write code like
struct MOCK(sender) mock_sender = CONSTRUCT_MOCK(sender, test);
/* Fake an error for a specific input. */
handle = KUNIT_EXPECT_CALL(send(<omitted>, kunit_int_eq(42)));
handle->action = kunit_int_return(test, -EINVAL);
/* Pass the mocked object to some code under test. */
KUNIT_EXPECT_EQ(test, -EINVAL, send_message(...));
I.e. the goal is to make it easier to test
1) with less dependencies (we don't need to setup a real `sender`)
2) unusual/error conditions more easily.
In the future, we hope to build upon this to support mocking in more
contexts, e.g. standalone funcs, etc.
# TODOs
## Naming
This introduces a number of new macros for dealing with mocks,
e.g:
DEFINE_STRUCT_CLASS_MOCK(METHOD(foo), CLASS(example),
RETURNS(int),
PARAMS(struct example *, int));
...
KUNIT_EXPECT_CALL(foo(mock_get_ctrl(mock_example), ...);
For consistency, we could prefix everything with KUNIT, e.g.
`KUNIT_DEFINE_STRUCT_CLASS_MOCK` and `kunit_mock_get_ctrl`, but it feels
like the names might be long enough that they would hinder readability.
## Usage
For now the only use of class mocking is in kunit-example-test.c
As part of changing this from an RFC to a real patch set, we're hoping
to include at least one example.
Pointers to bits of code where this would be useful that aren't too
hairy would be appreciated.
E.g. could easily add a test for tools/perf/ui/progress.h, e.g. that
ui_progress__init() calls ui_progress_ops.init(), but that likely isn't
useful to anyone.
Brendan Higgins (9):
kunit: test: add kunit_stream a std::stream like logger
kunit: test: add concept of post conditions
checkpatch: add support for struct MOCK(foo) syntax
kunit: mock: add parameter list manipulation macros
kunit: mock: add internal mock infrastructure
kunit: mock: add basic matchers and actions
kunit: mock: add class mocking support
kunit: mock: add struct param matcher
kunit: mock: implement nice, strict and naggy mock distinctions
Daniel Latypov (2):
Revert "kunit: move string-stream.h to lib/kunit"
kunit: expose kunit_set_failure() for use by mocking
Marcelo Schmitt (1):
kunit: mock: add macro machinery to pick correct format args
include/kunit/assert.h | 3 +-
include/kunit/kunit-stream.h | 94 +++
include/kunit/mock.h | 902 +++++++++++++++++++++++++
include/kunit/params.h | 305 +++++++++
{lib => include}/kunit/string-stream.h | 2 +
include/kunit/test.h | 9 +
lib/kunit/Makefile | 9 +-
lib/kunit/assert.c | 2 -
lib/kunit/common-mocks.c | 409 +++++++++++
lib/kunit/kunit-example-test.c | 90 +++
lib/kunit/kunit-stream.c | 110 +++
lib/kunit/mock-macro-test.c | 241 +++++++
lib/kunit/mock-test.c | 531 +++++++++++++++
lib/kunit/mock.c | 370 ++++++++++
lib/kunit/string-stream-test.c | 3 +-
lib/kunit/string-stream.c | 5 +-
lib/kunit/test.c | 15 +-
scripts/checkpatch.pl | 4 +
18 files changed, 3091 insertions(+), 13 deletions(-)
create mode 100644 include/kunit/kunit-stream.h
create mode 100644 include/kunit/mock.h
create mode 100644 include/kunit/params.h
rename {lib => include}/kunit/string-stream.h (95%)
create mode 100644 lib/kunit/common-mocks.c
create mode 100644 lib/kunit/kunit-stream.c
create mode 100644 lib/kunit/mock-macro-test.c
create mode 100644 lib/kunit/mock-test.c
create mode 100644 lib/kunit/mock.c
base-commit: 10b82d5176488acee2820e5a2cf0f2ec5c3488b6
--
2.28.0.681.g6f77f65b4e-goog
CalledProcessError stores the output of the failed process as `bytes`,
not a `str`.
So when we log it on build error, the make output is all crammed into
one line with "\n" instead of actually printing new lines.
After this change, we get readable output with new lines, e.g.
> CC lib/kunit/kunit-example-test.o
> In file included from ../lib/kunit/test.c:9:
> ../include/kunit/test.h:22:1: error: unknown type name ‘invalid_type_that_causes_compile’
> 22 | invalid_type_that_causes_compile errors;
> | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> make[3]: *** [../scripts/Makefile.build:283: lib/kunit/test.o] Error 1
Secondly, trying to concat exceptions to strings will fail with
> TypeError: can only concatenate str (not "OSError") to str
so fix this with an explicit cast to str.
Signed-off-by: Daniel Latypov <dlatypov(a)google.com>
---
tools/testing/kunit/kunit_kernel.py | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)
diff --git a/tools/testing/kunit/kunit_kernel.py b/tools/testing/kunit/kunit_kernel.py
index e20e2056cb38..0e19089f62f0 100644
--- a/tools/testing/kunit/kunit_kernel.py
+++ b/tools/testing/kunit/kunit_kernel.py
@@ -36,9 +36,9 @@ class LinuxSourceTreeOperations(object):
try:
subprocess.check_output(['make', 'mrproper'], stderr=subprocess.STDOUT)
except OSError as e:
- raise ConfigError('Could not call make command: ' + e)
+ raise ConfigError('Could not call make command: ' + str(e))
except subprocess.CalledProcessError as e:
- raise ConfigError(e.output)
+ raise ConfigError(e.output.decode())
def make_olddefconfig(self, build_dir, make_options):
command = ['make', 'ARCH=um', 'olddefconfig']
@@ -49,9 +49,9 @@ class LinuxSourceTreeOperations(object):
try:
subprocess.check_output(command, stderr=subprocess.STDOUT)
except OSError as e:
- raise ConfigError('Could not call make command: ' + e)
+ raise ConfigError('Could not call make command: ' + str(e))
except subprocess.CalledProcessError as e:
- raise ConfigError(e.output)
+ raise ConfigError(e.output.decode())
def make_allyesconfig(self):
kunit_parser.print_with_timestamp(
@@ -79,9 +79,9 @@ class LinuxSourceTreeOperations(object):
try:
subprocess.check_output(command, stderr=subprocess.STDOUT)
except OSError as e:
- raise BuildError('Could not call execute make: ' + e)
+ raise BuildError('Could not call execute make: ' + str(e))
except subprocess.CalledProcessError as e:
- raise BuildError(e.output)
+ raise BuildError(e.output.decode())
def linux_bin(self, params, timeout, build_dir, outfile):
"""Runs the Linux UML binary. Must be named 'linux'."""
base-commit: ccc1d052eff9f3cfe59d201263903fe1d46c79a5
--
2.28.0.709.gb0816b6eb0-goog
v2 -> v3:
- Rename functions and variables in verifier for better readability.
- Stick to logging message convention in libbpf.
- Move bpf_per_cpu_ptr and bpf_this_cpu_ptr from trace-specific
helper set to base helper set.
- More specific test in ksyms_btf.
- Fix return type cast in bpf_*_cpu_ptr.
- Fix btf leak in ksyms_btf selftest.
- Fix return error code for kallsyms_find().
v1 -> v2:
- Move check_pseudo_btf_id from check_ld_imm() to
replace_map_fd_with_map_ptr() and rename the latter.
- Add bpf_this_cpu_ptr().
- Use bpf_core_types_are_compat() in libbpf.c for checking type
compatibility.
- Rewrite typed ksym extern type in BTF with int to save space.
- Minor revision of bpf_per_cpu_ptr()'s comments.
- Avoid using long in tests that use skeleton.
- Refactored test_ksyms.c by moving kallsyms_find() to trace_helpers.c
- Fold the patches that sync include/linux/uapi and
tools/include/linux/uapi.
rfc -> v1:
- Encode VAR's btf_id for PSEUDO_BTF_ID.
- More checks in verifier. Checking the btf_id passed as
PSEUDO_BTF_ID is valid VAR, its name and type.
- Checks in libbpf on type compatibility of ksyms.
- Add bpf_per_cpu_ptr() to access kernel percpu vars. Introduced
new ARG and RET types for this helper.
This patch series extends the previously added __ksym externs with
btf support.
Right now the __ksym externs are treated as pure 64-bit scalar value.
Libbpf replaces ld_imm64 insn of __ksym by its kernel address at load
time. This patch series extend those externs with their btf info. Note
that btf support for __ksym must come with the kernel btf that has
VARs encoded to work properly. The corresponding chagnes in pahole
is available at [1] (with a fix at [2] for gcc 4.9+).
The first 3 patches in this series add support for general kernel
global variables, which include verifier checking (01/06), libpf
support (02/06) and selftests for getting typed ksym extern's kernel
address (03/06).
The next 3 patches extends that capability further by introducing
helpers bpf_per_cpu_ptr() and bpf_this_cpu_ptr(), which allows accessing
kernel percpu variables correctly (04/06 and 05/06).
The tests of this feature were performed against pahole that is extended
with [1] and [2]. For kernel BTF that does not have VARs encoded, the
selftests will be skipped.
[1] https://git.kernel.org/pub/scm/devel/pahole/pahole.git/commit/?id=f3d9054ba…
[2] https://www.spinics.net/lists/dwarves/msg00451.html
Hao Luo (6):
bpf: Introduce pseudo_btf_id
bpf/libbpf: BTF support for typed ksyms
selftests/bpf: ksyms_btf to test typed ksyms
bpf: Introduce bpf_per_cpu_ptr()
bpf: Introduce bpf_this_cpu_ptr()
bpf/selftests: Test for bpf_per_cpu_ptr() and bpf_this_cpu_ptr()
include/linux/bpf.h | 6 +
include/linux/bpf_verifier.h | 7 +
include/linux/btf.h | 26 +++
include/uapi/linux/bpf.h | 67 +++++-
kernel/bpf/btf.c | 25 ---
kernel/bpf/helpers.c | 32 +++
kernel/bpf/verifier.c | 190 ++++++++++++++++--
kernel/trace/bpf_trace.c | 4 +
tools/include/uapi/linux/bpf.h | 67 +++++-
tools/lib/bpf/libbpf.c | 112 +++++++++--
.../testing/selftests/bpf/prog_tests/ksyms.c | 38 ++--
.../selftests/bpf/prog_tests/ksyms_btf.c | 88 ++++++++
.../selftests/bpf/progs/test_ksyms_btf.c | 55 +++++
tools/testing/selftests/bpf/trace_helpers.c | 27 +++
tools/testing/selftests/bpf/trace_helpers.h | 4 +
15 files changed, 653 insertions(+), 95 deletions(-)
create mode 100644 tools/testing/selftests/bpf/prog_tests/ksyms_btf.c
create mode 100644 tools/testing/selftests/bpf/progs/test_ksyms_btf.c
--
2.28.0.618.gf4bc123cb7-goog
This is based on the latest mmotm.
Summary: This series provides two main things, and a number of smaller
supporting goodies. The two main points are:
1) Add a new sub-test to gup_test, which in turn is a renamed version of
gup_benchmark. This sub-test allows nicer testing of dump_pages(), at
least on user-space pages.
For quite a while, I was doing a quick hack to gup_test.c whenever I
wanted to try out changes to dump_page(). Then Matthew Wilcox asked me
what I meant when I said "I used my dump_page() unit test", and I
realized that it might be nice to check in a polished up version of
that.
Details about how it works and how to use it are in the commit
description for patch #6.
2) Fixes a limitation of hmm-tests: these tests are incredibly useful,
but only if people actually build and run them. And it turns out that
libhugetlbfs is a little too effective at throwing a wrench in the
works, there. So I've added a little configuration check that removes
just two of the 21 hmm-tests, if libhugetlbfs is not available.
Further details in the commit description of patch #8.
Other smaller things that this series does:
a) Remove code duplication by creating gup_test.h.
b) Clear up the sub-test organization, and their invocation within
run_vmtests.sh.
c) Other minor assorted improvements.
John Hubbard (8):
mm/gup_benchmark: rename to mm/gup_test
selftests/vm: use a common gup_test.h
selftests/vm: rename run_vmtests --> run_vmtests.sh
selftests/vm: minor cleanup: Makefile and gup_test.c
selftests/vm: only some gup_test items are really benchmarks
selftests/vm: gup_test: introduce the dump_pages() sub-test
selftests/vm: run_vmtest.sh: update and clean up gup_test invocation
selftests/vm: hmm-tests: remove the libhugetlbfs dependency
Documentation/core-api/pin_user_pages.rst | 6 +-
arch/s390/configs/debug_defconfig | 2 +-
arch/s390/configs/defconfig | 2 +-
mm/Kconfig | 21 +-
mm/Makefile | 2 +-
mm/{gup_benchmark.c => gup_test.c} | 109 ++++++----
mm/gup_test.h | 32 +++
tools/testing/selftests/vm/.gitignore | 3 +-
tools/testing/selftests/vm/Makefile | 38 +++-
tools/testing/selftests/vm/check_config.sh | 30 +++
tools/testing/selftests/vm/config | 2 +-
tools/testing/selftests/vm/gup_benchmark.c | 137 -------------
tools/testing/selftests/vm/gup_test.c | 188 ++++++++++++++++++
tools/testing/selftests/vm/hmm-tests.c | 10 +-
.../vm/{run_vmtests => run_vmtest.sh} | 24 ++-
15 files changed, 403 insertions(+), 203 deletions(-)
rename mm/{gup_benchmark.c => gup_test.c} (59%)
create mode 100644 mm/gup_test.h
create mode 100755 tools/testing/selftests/vm/check_config.sh
delete mode 100644 tools/testing/selftests/vm/gup_benchmark.c
create mode 100644 tools/testing/selftests/vm/gup_test.c
rename tools/testing/selftests/vm/{run_vmtests => run_vmtest.sh} (91%)
--
2.28.0
On Mon, Sep 14 2020 at 15:24, Linus Torvalds wrote:
> On Mon, Sep 14, 2020 at 2:55 PM Thomas Gleixner <tglx(a)linutronix.de> wrote:
>>
>> Yes it does generate better code, but I tried hard to spot a difference
>> in various metrics exposed by perf. It's all in the noise and I only
>> can spot a difference when the actual preemption check after the
>> decrement
>
> I'm somewhat more worried about the small-device case.
I just checked on one of my old UP ARM toys which I run at home. The .text
increase is about 2% (75k) and none of the tests I ran showed any
significant difference. Couldn't verify with perf though as the PMU on
that piece of art is unusable.
> That said, the diffstat certainly has its very clear charm, and I do
> agree that it makes things simpler.
>
> I'm just not convinced people should ever EVER do things like that "if
> (preemptible())" garbage. It sounds like somebody is doing seriously
> bad things.
OTOH, having a working 'preemptible()' or maybe better named
'can_schedule()' check makes tons of sense to make decisions about
allocation modes or other things.
We're currently looking through all of in_atomic(), in_interrupt()
etc. usage sites and quite some of them are historic and have the clear
intent of checking whether the code is called from task context or
hard/softirq context. Lots of them are completely broken or just work by
chance.
But there is clearly historic precendence that context checks are
useful, but they only can be useful if we have a consistent mechanism
which works everywhere.
Of course we could mandate that every interface which might be called
from one or the other context has a context argument or provides two
variants of the same thing. But I'm not really convinced whether that's
a win over having a consistent and reliable set of checks.
Thanks,
tglx