Re: [PATCH v4 2/2] tests/unit: Add an unit test for smp parsing

["Philippe Mathieu-Daudé" <philmd@redhat.com>]

On 11/11/21 10:31, wangyanan (Y) wrote:
> 
> On 2021/11/11 17:14, Philippe Mathieu-Daudé wrote:
>> On 10/28/21 17:09, Philippe Mathieu-Daudé wrote:
>>> From: Yanan Wang <wangyanan55@huawei.com>
>>>
>>> Now that we have a generic parser smp_parse(), let's add an unit
>>> test for the code. All possible valid/invalid SMP configurations
>>> that the user can specify are covered.
>>>
>>> Signed-off-by: Yanan Wang <wangyanan55@huawei.com>
>>> Reviewed-by: Andrew Jones <drjones@redhat.com>
>>> Tested-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>>> Message-Id: <20211026034659.22040-3-wangyanan55@huawei.com>
>>> Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
>>> ---
>>>   tests/unit/test-smp-parse.c | 594 ++++++++++++++++++++++++++++++++++++
>>>   MAINTAINERS                 |   1 +
>>>   tests/unit/meson.build      |   1 +
>>>   3 files changed, 596 insertions(+)
>>>   create mode 100644 tests/unit/test-smp-parse.c
>>> +static struct SMPTestData data_generic_valid[] = {
>>> +    {
>>> +        /* config: no configuration provided
>>> +         * expect: cpus=1,sockets=1,cores=1,threads=1,maxcpus=1 */
>> [1]
>>
>>> +        .config = SMP_CONFIG_GENERIC(F, 0, F, 0, F, 0, F, 0, F, 0),
>>> +        .expect_prefer_sockets = CPU_TOPOLOGY_GENERIC(1, 1, 1, 1, 1),
>>> +        .expect_prefer_cores   = CPU_TOPOLOGY_GENERIC(1, 1, 1, 1, 1),
>>> +    }, {
>>> +static void test_generic(void)
>>> +{
>>> +    Object *obj = object_new(TYPE_MACHINE);
>>> +    MachineState *ms = MACHINE(obj);
>>> +    MachineClass *mc = MACHINE_GET_CLASS(obj);
>> Watch out, while you create a machine instance in each
>> test, there is only one machine class registered (see
>> type_register_static(&smp_machine_info) below in [2]),
>> ...
> Yes, I noticed this. So on the top of each sub-test function, the
> properties
> of the single machine class is re-initialized by
> smp_machine_class_init(mc).
> See [*] below.
>>> +    SMPTestData *data = &(SMPTestData){0};
>>> +    int i;
>>> +
>>> +    smp_machine_class_init(mc);
> [*]
>>> +
>>> +    for (i = 0; i < ARRAY_SIZE(data_generic_valid); i++) {
>>> +        *data = data_generic_valid[i];
>>> +        unsupported_params_init(mc, data);
>>> +
>>> +        smp_parse_test(ms, data, true);
>>> +
>>> +        /* Unsupported parameters can be provided with their values
>>> as 1 */
>>> +        data->config.has_dies = true;
>>> +        data->config.dies = 1;
>>> +        smp_parse_test(ms, data, true);
>>> +    }
>>> +
>>> +    /* Reset the supported min CPUs and max CPUs */
>>> +    mc->min_cpus = 2;
>>> +    mc->max_cpus = 511;
>> ... and here you are modifying the single machine class state, ...
>>
>>> +
>>> +    for (i = 0; i < ARRAY_SIZE(data_generic_invalid); i++) {
>>> +        *data = data_generic_invalid[i];
>>> +        unsupported_params_init(mc, data);
>>> +
>>> +        smp_parse_test(ms, data, false);
>>> +    }
>>> +
>>> +    object_unref(obj);
>>> +}
>>> +
>>> +static void test_with_dies(void)
>>> +{
>>> +    Object *obj = object_new(TYPE_MACHINE);
>>> +    MachineState *ms = MACHINE(obj);
>>> +    MachineClass *mc = MACHINE_GET_CLASS(obj);
>> ... so here the machine class state is inconsistent, ...
>>
>>> +    SMPTestData *data = &(SMPTestData){0};
>>> +    unsigned int num_dies = 2;
>>> +    int i;
>>> +
>>> +    smp_machine_class_init(mc);
> And here [*].
>>> +    mc->smp_props.dies_supported = true;
>>> +
>>> +    for (i = 0; i < ARRAY_SIZE(data_generic_valid); i++) {
>>> +        *data = data_generic_valid[i];
>>> +        unsupported_params_init(mc, data);
>>> +
>>> +        /* when dies parameter is omitted, it will be set as 1 */
>>> +        data->expect_prefer_sockets.dies = 1;
>>> +        data->expect_prefer_cores.dies = 1;
>>> +
>>> +        smp_parse_test(ms, data, true);
>> ... in particular the first test [1] is tested with mc->min_cpus = 2.
>>
>> I wonder why you are not getting:
>>
>> Output error report: Invalid SMP CPUs 1. The min CPUs supported by
>> machine '(null)' is 2
>>
>> for [1].
> So as I have explained above, we won't get an output error report like
> this here. :)

I see. IMHO this is bad practice example, so I'll send a cleanup patch.