[PATCH v1 14/17] Documentation: kunit: add documentation for KUnit

[Masayoshi Mizuma]

Hi Brendan,

KUNIT_ASSERT_NOT_ERR_OR_NULL() should be replaced to
KUNIT_EXPECT_NOT_ERR_OR_NULL(), right?

On Thu, Apr 04, 2019 at 03:06:49PM -0700, Brendan Higgins wrote:
> Add documentation for KUnit, the Linux kernel unit testing framework.
> - Add intro and usage guide for KUnit
> - Add API reference
> 
> Signed-off-by: Felix Guo <felixguoxiuping at gmail.com>
> Signed-off-by: Brendan Higgins <brendanhiggins at google.com>
> ---

<snip>

> diff --git a/Documentation/kunit/start.rst b/Documentation/kunit/start.rst
> new file mode 100644
> index 0000000000000..5cdba5091905e
> --- /dev/null
> +++ b/Documentation/kunit/start.rst

<snip>

> +Assertions
> +~~~~~~~~~~
> +
> +KUnit also has the concept of an *assertion*. An assertion is just like an
> +expectation except the assertion immediately terminates the test case if it is
> +not satisfied.
> +
> +For example:
> +
> +.. code-block:: c
> +
> +	static void mock_test_do_expect_default_return(struct kunit *test)
> +	{
> +		struct mock_test_context *ctx = test->priv;
> +		struct mock *mock = ctx->mock;
> +		int param0 = 5, param1 = -5;
> +		const char *two_param_types[] = {"int", "int"};
> +		const void *two_params[] = {&param0, &param1};
> +		const void *ret;
> +
> +		ret = mock->do_expect(mock,
> +				      "test_printk", test_printk,
> +				      two_param_types, two_params,
> +				      ARRAY_SIZE(two_params));

> +		KUNIT_ASSERT_NOT_ERR_OR_NULL(test, ret);

		KUNIT_EXPECT_NOT_ERR_OR_NULL(test, ret);

> +		KUNIT_EXPECT_EQ(test, -4, *((int *) ret));
> +	}
> +
> +In this example, the method under test should return a pointer to a value, so
> +if the pointer returned by the method is null or an errno, we don't want to
> +bother continuing the test since the following expectation could crash the test

> +case. `ASSERT_NOT_ERR_OR_NULL(...)` allows us to bail out of the test case if

  +case. `KUNIT_EXPECT_NOT_ERR_OR_NULL(...)` allows us to bail out of the test case if

Thanks!
Masa