[RFC,v6,3/4] fpga: add an initial KUnit suite for the FPGA Region

  The suite tests the programming of an FPGA Region with a Bridge
and the function for finding a particular Region.

Signed-off-by: Marco Pagani <marpagan@redhat.com>
---
 drivers/fpga/tests/fpga-region-test.c | 186 ++++++++++++++++++++++++++
 1 file changed, 186 insertions(+)
 create mode 100644 drivers/fpga/tests/fpga-region-test.c
  

On 2023-05-31 at 11:54:04 +0200, Marco Pagani wrote:
> The suite tests the programming of an FPGA Region with a Bridge
> and the function for finding a particular Region.
> 
> Signed-off-by: Marco Pagani <marpagan@redhat.com>
> ---
>  drivers/fpga/tests/fpga-region-test.c | 186 ++++++++++++++++++++++++++
>  1 file changed, 186 insertions(+)
>  create mode 100644 drivers/fpga/tests/fpga-region-test.c
> 
> diff --git a/drivers/fpga/tests/fpga-region-test.c b/drivers/fpga/tests/fpga-region-test.c
> new file mode 100644
> index 000000000000..81b271088240
> --- /dev/null
> +++ b/drivers/fpga/tests/fpga-region-test.c
> @@ -0,0 +1,186 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * KUnit test for the FPGA Region
> + *
> + * Copyright (C) 2023 Red Hat, Inc.
> + *
> + * Author: Marco Pagani <marpagan@redhat.com>
> + */
> +
> +#include <linux/types.h>
> +#include <linux/module.h>
> +#include <kunit/test.h>
> +#include <linux/platform_device.h>
> +#include <linux/fpga/fpga-mgr.h>
> +#include <linux/fpga/fpga-bridge.h>
> +#include <linux/fpga/fpga-region.h>
> +
> +struct mgr_stats {
> +	u32 write_count;
> +};
> +
> +struct bridge_stats {
> +	u32 enable_count;
> +};
> +
> +struct test_ctx {
> +	struct fpga_manager *mgr;
> +	struct platform_device *mgr_pdev;
> +	struct fpga_bridge *bridge;
> +	struct platform_device *bridge_pdev;
> +	struct fpga_region *region;
> +	struct platform_device *region_pdev;
> +	struct bridge_stats bridge_stats;
> +	struct mgr_stats mgr_stats;
> +};
> +
> +static int op_write(struct fpga_manager *mgr, const char *buf, size_t count)
> +{
> +	struct mgr_stats *stats = mgr->priv;
> +
> +	stats->write_count++;
> +
> +	return 0;
> +}
> +
> +static const struct fpga_manager_ops fake_mgr_ops = {
> +	.write = op_write,
> +};

Maybe better just put all tests in one module, and have unified
fake_mgr_ops/mgr_stats/fake_bridge_ops/bridge_stats across all tests.

In previous thread, I said I'm good to the self-contained test module
but I didn't actually follow the idea. Sorry for that.

The concern is why in this region test, the write_count and only the
write_count is taken care of.

Although fpga_mgr_load() test covers all mgr_ops, but does that
means these ops are still good for more complex case like
fpga_region_program_fpga()? And there is no guarantee
fpga_region_program_fpga() would always call mgr_ops the same way
as fpga_mgr_load() in future.

Similar for fpga_bridge. Maybe a complete setup for fpga_region is
still necessary.

BTW: I like the way that fake drivers are removed. Looks much straight
forward.

Thanks,
Yilun

> +
> +static int op_enable_set(struct fpga_bridge *bridge, bool enable)
> +{
> +	struct bridge_stats *stats = bridge->priv;
> +
> +	if (enable)
> +		stats->enable_count++;
> +
> +	return 0;
> +}
> +
> +static const struct fpga_bridge_ops fake_bridge_ops = {
> +	.enable_set = op_enable_set
> +};
> +
> +static int fake_region_get_bridges(struct fpga_region *region)
> +{
> +	struct fpga_bridge *bridge = region->priv;
> +
> +	return fpga_bridge_get_to_list(bridge->dev.parent, region->info, &region->bridge_list);
> +}
> +
> +static int fake_region_match(struct device *dev, const void *data)
> +{
> +	return dev->parent == data;
> +}
> +
> +static void fpga_region_test_class_find(struct kunit *test)
> +{
> +	struct test_ctx *ctx = test->priv;
> +	struct fpga_region *region;
> +
> +	region = fpga_region_class_find(NULL, &ctx->region_pdev->dev, fake_region_match);
> +	KUNIT_EXPECT_PTR_EQ(test, region, ctx->region);
> +}
> +
> +static void fpga_region_test_program_fpga(struct kunit *test)
> +{
> +	struct test_ctx *ctx = test->priv;
> +	struct fpga_image_info *img_info;
> +	char img_buf[4];
> +	int ret;
> +
> +	img_info = fpga_image_info_alloc(&ctx->mgr_pdev->dev);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, img_info);
> +
> +	img_info->buf = img_buf;
> +	img_info->count = sizeof(img_buf);
> +
> +	ctx->region->info = img_info;
> +	ret = fpga_region_program_fpga(ctx->region);
> +	KUNIT_ASSERT_EQ(test, ret, 0);
> +
> +	KUNIT_EXPECT_EQ(test, 1, ctx->mgr_stats.write_count);
> +	KUNIT_EXPECT_EQ(test, 1, ctx->bridge_stats.enable_count);
> +
> +	fpga_bridges_put(&ctx->region->bridge_list);
> +
> +	ret = fpga_region_program_fpga(ctx->region);
> +	KUNIT_ASSERT_EQ(test, ret, 0);
> +
> +	KUNIT_EXPECT_EQ(test, 2, ctx->mgr_stats.write_count);
> +	KUNIT_EXPECT_EQ(test, 2, ctx->bridge_stats.enable_count);
> +
> +	fpga_bridges_put(&ctx->region->bridge_list);
> +
> +	fpga_image_info_free(img_info);
> +}
> +
> +static int fpga_region_test_init(struct kunit *test)
> +{
> +	struct test_ctx *ctx;
> +	struct fpga_region_info region_info = { 0 };
> +
> +	ctx = kunit_kzalloc(test, sizeof(*ctx), GFP_KERNEL);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ctx);
> +
> +	ctx->mgr_pdev = platform_device_register_simple("mgr_pdev", PLATFORM_DEVID_AUTO, NULL, 0);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ctx->mgr_pdev);
> +
> +	ctx->mgr = devm_fpga_mgr_register(&ctx->mgr_pdev->dev, "Fake FPGA Manager", &fake_mgr_ops,
> +					  &ctx->mgr_stats);
> +	KUNIT_ASSERT_FALSE(test, IS_ERR_OR_NULL(ctx->mgr));
> +
> +	ctx->bridge_pdev = platform_device_register_simple("bridge_pdev", PLATFORM_DEVID_AUTO,
> +							   NULL, 0);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ctx->bridge_pdev);
> +
> +	ctx->bridge = fpga_bridge_register(&ctx->bridge_pdev->dev, "Fake FPGA Bridge",
> +					   &fake_bridge_ops, &ctx->bridge_stats);
> +	KUNIT_ASSERT_FALSE(test, IS_ERR_OR_NULL(ctx->bridge));
> +
> +	ctx->region_pdev = platform_device_register_simple("region_pdev", PLATFORM_DEVID_AUTO,
> +							   NULL, 0);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ctx->region_pdev);
> +
> +	region_info.mgr = ctx->mgr;
> +	region_info.priv = ctx->bridge;
> +	region_info.get_bridges = fake_region_get_bridges;
> +
> +	ctx->region = fpga_region_register_full(&ctx->region_pdev->dev, &region_info);
> +	KUNIT_ASSERT_FALSE(test, IS_ERR_OR_NULL(ctx->region));
> +
> +	test->priv = ctx;
> +
> +	return 0;
> +}
> +
> +static void fpga_region_test_exit(struct kunit *test)
> +{
> +	struct test_ctx *ctx = test->priv;
> +
> +	fpga_region_unregister(ctx->region);
> +	platform_device_unregister(ctx->region_pdev);
> +
> +	fpga_bridge_unregister(ctx->bridge);
> +	platform_device_unregister(ctx->bridge_pdev);
> +
> +	platform_device_unregister(ctx->mgr_pdev);
> +}
> +
> +static struct kunit_case fpga_region_test_cases[] = {
> +	KUNIT_CASE(fpga_region_test_class_find),
> +	KUNIT_CASE(fpga_region_test_program_fpga),
> +
> +	{}
> +};
> +
> +static struct kunit_suite fpga_region_suite = {
> +	.name = "fpga_mgr",
> +	.init = fpga_region_test_init,
> +	.exit = fpga_region_test_exit,
> +	.test_cases = fpga_region_test_cases,
> +};
> +
> +kunit_test_suite(fpga_region_suite);
> +
> +MODULE_LICENSE("GPL");
> -- 
> 2.40.1
>
  

On 2023-06-03 21:11, Xu Yilun wrote:
> On 2023-05-31 at 11:54:04 +0200, Marco Pagani wrote:
>> The suite tests the programming of an FPGA Region with a Bridge
>> and the function for finding a particular Region.
>>
>> Signed-off-by: Marco Pagani <marpagan@redhat.com>
>> ---
>>  drivers/fpga/tests/fpga-region-test.c | 186 ++++++++++++++++++++++++++
>>  1 file changed, 186 insertions(+)
>>  create mode 100644 drivers/fpga/tests/fpga-region-test.c

[...]

 
> Maybe better just put all tests in one module, and have unified
> fake_mgr_ops/mgr_stats/fake_bridge_ops/bridge_stats across all tests.
> 
> In previous thread, I said I'm good to the self-contained test module
> but I didn't actually follow the idea. Sorry for that.
> 
> The concern is why in this region test, the write_count and only the
> write_count is taken care of.
> 
> Although fpga_mgr_load() test covers all mgr_ops, but does that
> means these ops are still good for more complex case like
> fpga_region_program_fpga()? And there is no guarantee
> fpga_region_program_fpga() would always call mgr_ops the same way
> as fpga_mgr_load() in future.
> 
> Similar for fpga_bridge. Maybe a complete setup for fpga_region is
> still necessary.

I think that putting all tests in a single module (like in previous
versions) goes against the principles of unit testing, making the
code more similar to an integration test.

Unit tests should be focused on a single behavior. The programming
test case included in the Region's suite should test only the behavior
of the Region itself. Specifically, that fpga_region_program_fpga() calls
get_bridges(), to get and control bridges, and then the Manager for the
actual programming.

The programming sequence itself is outside the responsibilities of the
Region, and its correctness is already ensured by the Manager suite.
Similarly, the correctness of the Bridge's methods used by the Region
for getting and controlling multiple bridges is already ensured by the
Bridge test suite.

For this reason, the Manager and Bridge fakes used in the Region suite
implement only the minimal set of operations necessary to ensure the
correctness of the Region's behavior. If I used a "full" Manager (and
tested all mgr_ops), then the test case would have become an integration
test rather than a unit test for the Region.
> BTW: I like the way that fake drivers are removed. Looks much straight
> forward.

I appreciate that.
 
> Thanks,
> Yilun
>

Thanks,
Marco

[...]
  

On 2023-06-05 at 18:58:56 +0200, Marco Pagani wrote:
> 
> 
> On 2023-06-03 21:11, Xu Yilun wrote:
> > On 2023-05-31 at 11:54:04 +0200, Marco Pagani wrote:
> >> The suite tests the programming of an FPGA Region with a Bridge
> >> and the function for finding a particular Region.
> >>
> >> Signed-off-by: Marco Pagani <marpagan@redhat.com>
> >> ---
> >>  drivers/fpga/tests/fpga-region-test.c | 186 ++++++++++++++++++++++++++
> >>  1 file changed, 186 insertions(+)
> >>  create mode 100644 drivers/fpga/tests/fpga-region-test.c
> 
> [...]
> 
>  
> > Maybe better just put all tests in one module, and have unified
> > fake_mgr_ops/mgr_stats/fake_bridge_ops/bridge_stats across all tests.
> > 
> > In previous thread, I said I'm good to the self-contained test module
> > but I didn't actually follow the idea. Sorry for that.
> > 
> > The concern is why in this region test, the write_count and only the
> > write_count is taken care of.
> > 
> > Although fpga_mgr_load() test covers all mgr_ops, but does that
> > means these ops are still good for more complex case like
> > fpga_region_program_fpga()? And there is no guarantee
> > fpga_region_program_fpga() would always call mgr_ops the same way
> > as fpga_mgr_load() in future.
> > 
> > Similar for fpga_bridge. Maybe a complete setup for fpga_region is
> > still necessary.
> 
> I think that putting all tests in a single module (like in previous
> versions) goes against the principles of unit testing, making the
> code more similar to an integration test.
> 
> Unit tests should be focused on a single behavior. The programming
> test case included in the Region's suite should test only the behavior
> of the Region itself. Specifically, that fpga_region_program_fpga() calls
> get_bridges(), to get and control bridges, and then the Manager for the
> actual programming.
> 
> The programming sequence itself is outside the responsibilities of the
> Region, and its correctness is already ensured by the Manager suite.
> Similarly, the correctness of the Bridge's methods used by the Region
> for getting and controlling multiple bridges is already ensured by the
> Bridge test suite.
> 
> For this reason, the Manager and Bridge fakes used in the Region suite
> implement only the minimal set of operations necessary to ensure the
> correctness of the Region's behavior. If I used a "full" Manager (and
> tested all mgr_ops), then the test case would have become an integration
> test rather than a unit test for the Region.

I agree with you about a unit test should focus on a single behavior. But
I have concerns that each test suite uses different definitions of the
same structure, mgr/bridge stats, mgr/bridge ops, mgr/bridge ctx. Even
if we have full definitions for these structures to acommodate all
tests, it doesn't break the principle of unit test, just ignore the fields
and skip checks that you don't care. E.g. only checks mgr.write_count &
bridge.enable_count for region test.

And a single module simplifies the implementation.

struct mgr_stats {
	...
};

struct mgr_ctx {
	struct fpga_image_info *img_info;
	struct fpga_manager *mgr;
	struct platform_device *pdev;
	struct mgr_stats stats;
};

struct bridge_stats {
	...
};

struct bridge_ctx {
	struct fpga_bridge *bridge;
	struct platform_device *pdev;
	struct bridge_stats stats;
};

struct region_ctx {
	struct mgr_ctx mgr_ctx;
	struct bridge_ctx bridge_ctx;

	struct fpga_region *region;
	struct platform_device *region_pdev;
};

How do you think?

Thanks,
Yilun

> > BTW: I like the way that fake drivers are removed. Looks much straight
> > forward.
> 
> I appreciate that.
>  
> > Thanks,
> > Yilun
> >
> 
> Thanks,
> Marco
> 
> [...]
>
  

On 2023-06-06 13:00, Xu Yilun wrote:
> On 2023-06-05 at 18:58:56 +0200, Marco Pagani wrote:
>>
>>
>> On 2023-06-03 21:11, Xu Yilun wrote:
>>> On 2023-05-31 at 11:54:04 +0200, Marco Pagani wrote:
>>>> The suite tests the programming of an FPGA Region with a Bridge
>>>> and the function for finding a particular Region.
>>>>
>>>> Signed-off-by: Marco Pagani <marpagan@redhat.com>
>>>> ---
>>>>  drivers/fpga/tests/fpga-region-test.c | 186 ++++++++++++++++++++++++++
>>>>  1 file changed, 186 insertions(+)
>>>>  create mode 100644 drivers/fpga/tests/fpga-region-test.c
>>
>> [...]
>>
>>  
>>> Maybe better just put all tests in one module, and have unified
>>> fake_mgr_ops/mgr_stats/fake_bridge_ops/bridge_stats across all tests.
>>>
>>> In previous thread, I said I'm good to the self-contained test module
>>> but I didn't actually follow the idea. Sorry for that.
>>>
>>> The concern is why in this region test, the write_count and only the
>>> write_count is taken care of.
>>>
>>> Although fpga_mgr_load() test covers all mgr_ops, but does that
>>> means these ops are still good for more complex case like
>>> fpga_region_program_fpga()? And there is no guarantee
>>> fpga_region_program_fpga() would always call mgr_ops the same way
>>> as fpga_mgr_load() in future.
>>>
>>> Similar for fpga_bridge. Maybe a complete setup for fpga_region is
>>> still necessary.
>>
>> I think that putting all tests in a single module (like in previous
>> versions) goes against the principles of unit testing, making the
>> code more similar to an integration test.
>>
>> Unit tests should be focused on a single behavior. The programming
>> test case included in the Region's suite should test only the behavior
>> of the Region itself. Specifically, that fpga_region_program_fpga() calls
>> get_bridges(), to get and control bridges, and then the Manager for the
>> actual programming.
>>
>> The programming sequence itself is outside the responsibilities of the
>> Region, and its correctness is already ensured by the Manager suite.
>> Similarly, the correctness of the Bridge's methods used by the Region
>> for getting and controlling multiple bridges is already ensured by the
>> Bridge test suite.
>>
>> For this reason, the Manager and Bridge fakes used in the Region suite
>> implement only the minimal set of operations necessary to ensure the
>> correctness of the Region's behavior. If I used a "full" Manager (and
>> tested all mgr_ops), then the test case would have become an integration
>> test rather than a unit test for the Region.
> 
> I agree with you about a unit test should focus on a single behavior. But
> I have concerns that each test suite uses different definitions of the
> same structure, mgr/bridge stats, mgr/bridge ops, mgr/bridge ctx. Even
> if we have full definitions for these structures to acommodate all
> tests, it doesn't break the principle of unit test, just ignore the fields
> and skip checks that you don't care. E.g. only checks mgr.write_count &
> bridge.enable_count for region test.
> 
> And a single module simplifies the implementation.
> 
> struct mgr_stats {
> 	...
> };
> 
> struct mgr_ctx {
> 	struct fpga_image_info *img_info;
> 	struct fpga_manager *mgr;
> 	struct platform_device *pdev;
> 	struct mgr_stats stats;
> };
> 
> struct bridge_stats {
> 	...
> };
> 
> struct bridge_ctx {
> 	struct fpga_bridge *bridge;
> 	struct platform_device *pdev;
> 	struct bridge_stats stats;
> };
> 
> struct region_ctx {
> 	struct mgr_ctx mgr_ctx;
> 	struct bridge_ctx bridge_ctx;
> 
> 	struct fpga_region *region;
> 	struct platform_device *region_pdev;
> };
> 
> How do you think?
> 
> Thanks,
> Yilun
>

My concern with unified fakes having the same ops, stats, and context structs
is that they would couple the test suites together. I think it's better to
have multiple fakes, each with the single responsibility of providing minimal
support for the component under test. Otherwise, we would end up having
overcomplicated fakes that implement the union (in the set theory sense of
the term) of all behaviors tested by all suites. By using these fakes, some
test cases might implicitly exercise behaviors that are outside their scope
(e.g., the Region programming test case calling all Manager ops). I feel
this would go against the principle of limiting the amount of code under test
to a single unit. 
Thanks,
Marco

>>> BTW: I like the way that fake drivers are removed. Looks much straight
>>> forward.
>>
>> I appreciate that.
>>  
>>> Thanks,
>>> Yilun
>>>
>>
>> Thanks,
>> Marco
>>
>> [...]
>>
>
  

On 2023-06-09 13:09, Xu Yilun wrote:
> On 2023-06-07 at 17:57:22 +0200, Marco Pagani wrote:
>>
>>
>> On 2023-06-06 13:00, Xu Yilun wrote:
>>> On 2023-06-05 at 18:58:56 +0200, Marco Pagani wrote:
>>>>
>>>>
>>>> On 2023-06-03 21:11, Xu Yilun wrote:
>>>>> On 2023-05-31 at 11:54:04 +0200, Marco Pagani wrote:
>>>>>> The suite tests the programming of an FPGA Region with a Bridge
>>>>>> and the function for finding a particular Region.
>>>>>>
>>>>>> Signed-off-by: Marco Pagani <marpagan@redhat.com>
>>>>>> ---
>>>>>>  drivers/fpga/tests/fpga-region-test.c | 186 ++++++++++++++++++++++++++
>>>>>>  1 file changed, 186 insertions(+)
>>>>>>  create mode 100644 drivers/fpga/tests/fpga-region-test.c
>>>>
>>>> [...]
>>>>
>>>>  
>>>>> Maybe better just put all tests in one module, and have unified
>>>>> fake_mgr_ops/mgr_stats/fake_bridge_ops/bridge_stats across all tests.
>>>>>
>>>>> In previous thread, I said I'm good to the self-contained test module
>>>>> but I didn't actually follow the idea. Sorry for that.
>>>>>
>>>>> The concern is why in this region test, the write_count and only the
>>>>> write_count is taken care of.
>>>>>
>>>>> Although fpga_mgr_load() test covers all mgr_ops, but does that
>>>>> means these ops are still good for more complex case like
>>>>> fpga_region_program_fpga()? And there is no guarantee
>>>>> fpga_region_program_fpga() would always call mgr_ops the same way
>>>>> as fpga_mgr_load() in future.
>>>>>
>>>>> Similar for fpga_bridge. Maybe a complete setup for fpga_region is
>>>>> still necessary.
>>>>
>>>> I think that putting all tests in a single module (like in previous
>>>> versions) goes against the principles of unit testing, making the
>>>> code more similar to an integration test.
>>>>
>>>> Unit tests should be focused on a single behavior. The programming
>>>> test case included in the Region's suite should test only the behavior
>>>> of the Region itself. Specifically, that fpga_region_program_fpga() calls
>>>> get_bridges(), to get and control bridges, and then the Manager for the
>>>> actual programming.
>>>>
>>>> The programming sequence itself is outside the responsibilities of the
>>>> Region, and its correctness is already ensured by the Manager suite.
>>>> Similarly, the correctness of the Bridge's methods used by the Region
>>>> for getting and controlling multiple bridges is already ensured by the
>>>> Bridge test suite.
>>>>
>>>> For this reason, the Manager and Bridge fakes used in the Region suite
>>>> implement only the minimal set of operations necessary to ensure the
>>>> correctness of the Region's behavior. If I used a "full" Manager (and
>>>> tested all mgr_ops), then the test case would have become an integration
>>>> test rather than a unit test for the Region.
>>>
>>> I agree with you about a unit test should focus on a single behavior. But
>>> I have concerns that each test suite uses different definitions of the
>>> same structure, mgr/bridge stats, mgr/bridge ops, mgr/bridge ctx. Even
>>> if we have full definitions for these structures to acommodate all
>>> tests, it doesn't break the principle of unit test, just ignore the fields
>>> and skip checks that you don't care. E.g. only checks mgr.write_count &
>>> bridge.enable_count for region test.
>>>
>>> And a single module simplifies the implementation.
>>>
>>> struct mgr_stats {
>>> 	...
>>> };
>>>
>>> struct mgr_ctx {
>>> 	struct fpga_image_info *img_info;
>>> 	struct fpga_manager *mgr;
>>> 	struct platform_device *pdev;
>>> 	struct mgr_stats stats;
>>> };
>>>
>>> struct bridge_stats {
>>> 	...
>>> };
>>>
>>> struct bridge_ctx {
>>> 	struct fpga_bridge *bridge;
>>> 	struct platform_device *pdev;
>>> 	struct bridge_stats stats;
>>> };
>>>
>>> struct region_ctx {
>>> 	struct mgr_ctx mgr_ctx;
>>> 	struct bridge_ctx bridge_ctx;
>>>
>>> 	struct fpga_region *region;
>>> 	struct platform_device *region_pdev;
>>> };
>>>
>>> How do you think?
>>>
>>> Thanks,
>>> Yilun
>>>
>>
>> My concern with unified fakes having the same ops, stats, and context structs
>> is that they would couple the test suites together. I think it's better to
>> have multiple fakes, each with the single responsibility of providing minimal
>> support for the component under test. Otherwise, we would end up having
>> overcomplicated fakes that implement the union (in the set theory sense of
>> the term) of all behaviors tested by all suites. By using these fakes, some
>> test cases might implicitly exercise behaviors that are outside their scope
>> (e.g., the Region programming test case calling all Manager ops). I feel
>> this would go against the principle of limiting the amount of code under test
>> to a single unit. 
> 
> OK. On second thought, it is good to me.
> 
> I think now the high level opens are all addressed. Will you keep on
> improving the patchset or make it stable for upstream? If the later, you
> may drop the RFC prefix.

I plan to stabilize the patchset for the upstream.

Thanks,
Marco

> 
> Thanks,
> Yilun
> 
>> Thanks,
>> Marco
>>
>>>>> BTW: I like the way that fake drivers are removed. Looks much straight
>>>>> forward.
>>>>
>>>> I appreciate that.
>>>>  
>>>>> Thanks,
>>>>> Yilun
>>>>>
>>>>
>>>> Thanks,
>>>> Marco
>>>>
>>>> [...]
>>>>
>>>
>>
>
  

On 2023-06-09 13:22, Xu Yilun wrote:
> On 2023-05-31 at 11:54:04 +0200, Marco Pagani wrote:
>> The suite tests the programming of an FPGA Region with a Bridge
>> and the function for finding a particular Region.
>>
>> Signed-off-by: Marco Pagani <marpagan@redhat.com>
>> ---
>>  drivers/fpga/tests/fpga-region-test.c | 186 ++++++++++++++++++++++++++
>>  1 file changed, 186 insertions(+)
>>  create mode 100644 drivers/fpga/tests/fpga-region-test.c
>>
>> diff --git a/drivers/fpga/tests/fpga-region-test.c b/drivers/fpga/tests/fpga-region-test.c
>> new file mode 100644
>> index 000000000000..81b271088240
>> --- /dev/null
>> +++ b/drivers/fpga/tests/fpga-region-test.c
>> @@ -0,0 +1,186 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * KUnit test for the FPGA Region
>> + *
>> + * Copyright (C) 2023 Red Hat, Inc.
>> + *
>> + * Author: Marco Pagani <marpagan@redhat.com>
>> + */
>> +
>> +#include <linux/types.h>
>> +#include <linux/module.h>
>> +#include <kunit/test.h>
>> +#include <linux/platform_device.h>
>> +#include <linux/fpga/fpga-mgr.h>
>> +#include <linux/fpga/fpga-bridge.h>
>> +#include <linux/fpga/fpga-region.h>
>> +
>> +struct mgr_stats {
>> +	u32 write_count;
>> +};
>> +
>> +struct bridge_stats {
>> +	u32 enable_count;
>> +};
>> +
>> +struct test_ctx {
>> +	struct fpga_manager *mgr;
>> +	struct platform_device *mgr_pdev;
>> +	struct fpga_bridge *bridge;
>> +	struct platform_device *bridge_pdev;
>> +	struct fpga_region *region;
>> +	struct platform_device *region_pdev;
>> +	struct bridge_stats bridge_stats;
>> +	struct mgr_stats mgr_stats;
>> +};
>> +
>> +static int op_write(struct fpga_manager *mgr, const char *buf, size_t count)
>> +{
>> +	struct mgr_stats *stats = mgr->priv;
>> +
>> +	stats->write_count++;
> 
> Could you add some comments to explain why only implement the write op
> to help region test? and why not choose write_complete or other callback?

Sure, I'll do that in the next version.

Thanks,
Marco


> Thanks,
> Yilun
>

[...]
  

On 2023-06-07 at 17:57:22 +0200, Marco Pagani wrote:
> 
> 
> On 2023-06-06 13:00, Xu Yilun wrote:
> > On 2023-06-05 at 18:58:56 +0200, Marco Pagani wrote:
> >>
> >>
> >> On 2023-06-03 21:11, Xu Yilun wrote:
> >>> On 2023-05-31 at 11:54:04 +0200, Marco Pagani wrote:
> >>>> The suite tests the programming of an FPGA Region with a Bridge
> >>>> and the function for finding a particular Region.
> >>>>
> >>>> Signed-off-by: Marco Pagani <marpagan@redhat.com>
> >>>> ---
> >>>>  drivers/fpga/tests/fpga-region-test.c | 186 ++++++++++++++++++++++++++
> >>>>  1 file changed, 186 insertions(+)
> >>>>  create mode 100644 drivers/fpga/tests/fpga-region-test.c
> >>
> >> [...]
> >>
> >>  
> >>> Maybe better just put all tests in one module, and have unified
> >>> fake_mgr_ops/mgr_stats/fake_bridge_ops/bridge_stats across all tests.
> >>>
> >>> In previous thread, I said I'm good to the self-contained test module
> >>> but I didn't actually follow the idea. Sorry for that.
> >>>
> >>> The concern is why in this region test, the write_count and only the
> >>> write_count is taken care of.
> >>>
> >>> Although fpga_mgr_load() test covers all mgr_ops, but does that
> >>> means these ops are still good for more complex case like
> >>> fpga_region_program_fpga()? And there is no guarantee
> >>> fpga_region_program_fpga() would always call mgr_ops the same way
> >>> as fpga_mgr_load() in future.
> >>>
> >>> Similar for fpga_bridge. Maybe a complete setup for fpga_region is
> >>> still necessary.
> >>
> >> I think that putting all tests in a single module (like in previous
> >> versions) goes against the principles of unit testing, making the
> >> code more similar to an integration test.
> >>
> >> Unit tests should be focused on a single behavior. The programming
> >> test case included in the Region's suite should test only the behavior
> >> of the Region itself. Specifically, that fpga_region_program_fpga() calls
> >> get_bridges(), to get and control bridges, and then the Manager for the
> >> actual programming.
> >>
> >> The programming sequence itself is outside the responsibilities of the
> >> Region, and its correctness is already ensured by the Manager suite.
> >> Similarly, the correctness of the Bridge's methods used by the Region
> >> for getting and controlling multiple bridges is already ensured by the
> >> Bridge test suite.
> >>
> >> For this reason, the Manager and Bridge fakes used in the Region suite
> >> implement only the minimal set of operations necessary to ensure the
> >> correctness of the Region's behavior. If I used a "full" Manager (and
> >> tested all mgr_ops), then the test case would have become an integration
> >> test rather than a unit test for the Region.
> > 
> > I agree with you about a unit test should focus on a single behavior. But
> > I have concerns that each test suite uses different definitions of the
> > same structure, mgr/bridge stats, mgr/bridge ops, mgr/bridge ctx. Even
> > if we have full definitions for these structures to acommodate all
> > tests, it doesn't break the principle of unit test, just ignore the fields
> > and skip checks that you don't care. E.g. only checks mgr.write_count &
> > bridge.enable_count for region test.
> > 
> > And a single module simplifies the implementation.
> > 
> > struct mgr_stats {
> > 	...
> > };
> > 
> > struct mgr_ctx {
> > 	struct fpga_image_info *img_info;
> > 	struct fpga_manager *mgr;
> > 	struct platform_device *pdev;
> > 	struct mgr_stats stats;
> > };
> > 
> > struct bridge_stats {
> > 	...
> > };
> > 
> > struct bridge_ctx {
> > 	struct fpga_bridge *bridge;
> > 	struct platform_device *pdev;
> > 	struct bridge_stats stats;
> > };
> > 
> > struct region_ctx {
> > 	struct mgr_ctx mgr_ctx;
> > 	struct bridge_ctx bridge_ctx;
> > 
> > 	struct fpga_region *region;
> > 	struct platform_device *region_pdev;
> > };
> > 
> > How do you think?
> > 
> > Thanks,
> > Yilun
> >
> 
> My concern with unified fakes having the same ops, stats, and context structs
> is that they would couple the test suites together. I think it's better to
> have multiple fakes, each with the single responsibility of providing minimal
> support for the component under test. Otherwise, we would end up having
> overcomplicated fakes that implement the union (in the set theory sense of
> the term) of all behaviors tested by all suites. By using these fakes, some
> test cases might implicitly exercise behaviors that are outside their scope
> (e.g., the Region programming test case calling all Manager ops). I feel
> this would go against the principle of limiting the amount of code under test
> to a single unit. 

OK. On second thought, it is good to me.

I think now the high level opens are all addressed. Will you keep on
improving the patchset or make it stable for upstream? If the later, you
may drop the RFC prefix.

Thanks,
Yilun

> Thanks,
> Marco
> 
> >>> BTW: I like the way that fake drivers are removed. Looks much straight
> >>> forward.
> >>
> >> I appreciate that.
> >>  
> >>> Thanks,
> >>> Yilun
> >>>
> >>
> >> Thanks,
> >> Marco
> >>
> >> [...]
> >>
> > 
>
  

On 2023-05-31 at 11:54:04 +0200, Marco Pagani wrote:
> The suite tests the programming of an FPGA Region with a Bridge
> and the function for finding a particular Region.
> 
> Signed-off-by: Marco Pagani <marpagan@redhat.com>
> ---
>  drivers/fpga/tests/fpga-region-test.c | 186 ++++++++++++++++++++++++++
>  1 file changed, 186 insertions(+)
>  create mode 100644 drivers/fpga/tests/fpga-region-test.c
> 
> diff --git a/drivers/fpga/tests/fpga-region-test.c b/drivers/fpga/tests/fpga-region-test.c
> new file mode 100644
> index 000000000000..81b271088240
> --- /dev/null
> +++ b/drivers/fpga/tests/fpga-region-test.c
> @@ -0,0 +1,186 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/*
> + * KUnit test for the FPGA Region
> + *
> + * Copyright (C) 2023 Red Hat, Inc.
> + *
> + * Author: Marco Pagani <marpagan@redhat.com>
> + */
> +
> +#include <linux/types.h>
> +#include <linux/module.h>
> +#include <kunit/test.h>
> +#include <linux/platform_device.h>
> +#include <linux/fpga/fpga-mgr.h>
> +#include <linux/fpga/fpga-bridge.h>
> +#include <linux/fpga/fpga-region.h>
> +
> +struct mgr_stats {
> +	u32 write_count;
> +};
> +
> +struct bridge_stats {
> +	u32 enable_count;
> +};
> +
> +struct test_ctx {
> +	struct fpga_manager *mgr;
> +	struct platform_device *mgr_pdev;
> +	struct fpga_bridge *bridge;
> +	struct platform_device *bridge_pdev;
> +	struct fpga_region *region;
> +	struct platform_device *region_pdev;
> +	struct bridge_stats bridge_stats;
> +	struct mgr_stats mgr_stats;
> +};
> +
> +static int op_write(struct fpga_manager *mgr, const char *buf, size_t count)
> +{
> +	struct mgr_stats *stats = mgr->priv;
> +
> +	stats->write_count++;

Could you add some comments to explain why only implement the write op
to help region test? and why not choose write_complete or other callback?

Thanks,
Yilun

> +
> +	return 0;
> +}
> +
> +static const struct fpga_manager_ops fake_mgr_ops = {
> +	.write = op_write,
> +};
> +
> +static int op_enable_set(struct fpga_bridge *bridge, bool enable)
> +{
> +	struct bridge_stats *stats = bridge->priv;
> +
> +	if (enable)
> +		stats->enable_count++;
> +
> +	return 0;
> +}
> +
> +static const struct fpga_bridge_ops fake_bridge_ops = {
> +	.enable_set = op_enable_set
> +};
> +
> +static int fake_region_get_bridges(struct fpga_region *region)
> +{
> +	struct fpga_bridge *bridge = region->priv;
> +
> +	return fpga_bridge_get_to_list(bridge->dev.parent, region->info, &region->bridge_list);
> +}
> +
> +static int fake_region_match(struct device *dev, const void *data)
> +{
> +	return dev->parent == data;
> +}
> +
> +static void fpga_region_test_class_find(struct kunit *test)
> +{
> +	struct test_ctx *ctx = test->priv;
> +	struct fpga_region *region;
> +
> +	region = fpga_region_class_find(NULL, &ctx->region_pdev->dev, fake_region_match);
> +	KUNIT_EXPECT_PTR_EQ(test, region, ctx->region);
> +}
> +
> +static void fpga_region_test_program_fpga(struct kunit *test)
> +{
> +	struct test_ctx *ctx = test->priv;
> +	struct fpga_image_info *img_info;
> +	char img_buf[4];
> +	int ret;
> +
> +	img_info = fpga_image_info_alloc(&ctx->mgr_pdev->dev);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, img_info);
> +
> +	img_info->buf = img_buf;
> +	img_info->count = sizeof(img_buf);
> +
> +	ctx->region->info = img_info;
> +	ret = fpga_region_program_fpga(ctx->region);
> +	KUNIT_ASSERT_EQ(test, ret, 0);
> +
> +	KUNIT_EXPECT_EQ(test, 1, ctx->mgr_stats.write_count);
> +	KUNIT_EXPECT_EQ(test, 1, ctx->bridge_stats.enable_count);
> +
> +	fpga_bridges_put(&ctx->region->bridge_list);
> +
> +	ret = fpga_region_program_fpga(ctx->region);
> +	KUNIT_ASSERT_EQ(test, ret, 0);
> +
> +	KUNIT_EXPECT_EQ(test, 2, ctx->mgr_stats.write_count);
> +	KUNIT_EXPECT_EQ(test, 2, ctx->bridge_stats.enable_count);
> +
> +	fpga_bridges_put(&ctx->region->bridge_list);
> +
> +	fpga_image_info_free(img_info);
> +}
> +
> +static int fpga_region_test_init(struct kunit *test)
> +{
> +	struct test_ctx *ctx;
> +	struct fpga_region_info region_info = { 0 };
> +
> +	ctx = kunit_kzalloc(test, sizeof(*ctx), GFP_KERNEL);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ctx);
> +
> +	ctx->mgr_pdev = platform_device_register_simple("mgr_pdev", PLATFORM_DEVID_AUTO, NULL, 0);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ctx->mgr_pdev);
> +
> +	ctx->mgr = devm_fpga_mgr_register(&ctx->mgr_pdev->dev, "Fake FPGA Manager", &fake_mgr_ops,
> +					  &ctx->mgr_stats);
> +	KUNIT_ASSERT_FALSE(test, IS_ERR_OR_NULL(ctx->mgr));
> +
> +	ctx->bridge_pdev = platform_device_register_simple("bridge_pdev", PLATFORM_DEVID_AUTO,
> +							   NULL, 0);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ctx->bridge_pdev);
> +
> +	ctx->bridge = fpga_bridge_register(&ctx->bridge_pdev->dev, "Fake FPGA Bridge",
> +					   &fake_bridge_ops, &ctx->bridge_stats);
> +	KUNIT_ASSERT_FALSE(test, IS_ERR_OR_NULL(ctx->bridge));
> +
> +	ctx->region_pdev = platform_device_register_simple("region_pdev", PLATFORM_DEVID_AUTO,
> +							   NULL, 0);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ctx->region_pdev);
> +
> +	region_info.mgr = ctx->mgr;
> +	region_info.priv = ctx->bridge;
> +	region_info.get_bridges = fake_region_get_bridges;
> +
> +	ctx->region = fpga_region_register_full(&ctx->region_pdev->dev, &region_info);
> +	KUNIT_ASSERT_FALSE(test, IS_ERR_OR_NULL(ctx->region));
> +
> +	test->priv = ctx;
> +
> +	return 0;
> +}
> +
> +static void fpga_region_test_exit(struct kunit *test)
> +{
> +	struct test_ctx *ctx = test->priv;
> +
> +	fpga_region_unregister(ctx->region);
> +	platform_device_unregister(ctx->region_pdev);
> +
> +	fpga_bridge_unregister(ctx->bridge);
> +	platform_device_unregister(ctx->bridge_pdev);
> +
> +	platform_device_unregister(ctx->mgr_pdev);
> +}
> +
> +static struct kunit_case fpga_region_test_cases[] = {
> +	KUNIT_CASE(fpga_region_test_class_find),
> +	KUNIT_CASE(fpga_region_test_program_fpga),
> +
> +	{}
> +};
> +
> +static struct kunit_suite fpga_region_suite = {
> +	.name = "fpga_mgr",
> +	.init = fpga_region_test_init,
> +	.exit = fpga_region_test_exit,
> +	.test_cases = fpga_region_test_cases,
> +};
> +
> +kunit_test_suite(fpga_region_suite);
> +
> +MODULE_LICENSE("GPL");
> -- 
> 2.40.1
>