[PATCH] iio: test: iio-test-format: add test case for char format

[PATCH] iio: test: iio-test-format: add test case for char format

[Raffaele Tranfaglia via B4 Relay]

From: Raffaele Tranfaglia <raffaele.tranfaglia@gmail.com>

IIO_VAL_CHAR is used by thermocouple drivers to report the
thermocouple type, but iio_format_value() has no test for it.

Add a test case that checks a single character is printed followed
by a newline.

Assisted-by: LLM
Signed-off-by: Raffaele Tranfaglia <raffaele.tranfaglia@gmail.com>
---
Tested with KUnit on arm64 QEMU: all 8 iio-format cases pass.
---
 drivers/iio/test/iio-test-format.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/drivers/iio/test/iio-test-format.c b/drivers/iio/test/iio-test-format.c
index e5d0a2ac4670..701c362695f3 100644
--- a/drivers/iio/test/iio-test-format.c
+++ b/drivers/iio/test/iio-test-format.c
@@ -197,6 +197,28 @@ static void iio_test_iio_format_value_multiple(struct kunit *test)
 	IIO_TEST_FORMAT_EXPECT_EQ(test, buf, ret, "1 -2 3 -4 5 \n");
 }
 
+static void iio_test_iio_format_value_char(struct kunit *test)
+{
+	char *buf;
+	int val;
+	int ret;
+
+	buf = kunit_kmalloc(test, PAGE_SIZE, GFP_KERNEL);
+	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, buf);
+
+	val = 'K';
+	ret = iio_format_value(buf, IIO_VAL_CHAR, 1, &val);
+	IIO_TEST_FORMAT_EXPECT_EQ(test, buf, ret, "K\n");
+
+	val = 'j';
+	ret = iio_format_value(buf, IIO_VAL_CHAR, 1, &val);
+	IIO_TEST_FORMAT_EXPECT_EQ(test, buf, ret, "j\n");
+
+	val = '0';
+	ret = iio_format_value(buf, IIO_VAL_CHAR, 1, &val);
+	IIO_TEST_FORMAT_EXPECT_EQ(test, buf, ret, "0\n");
+}
+
 static void iio_test_iio_format_value_integer_64(struct kunit *test)
 {
 	int values[2];
@@ -308,6 +330,7 @@ static struct kunit_case iio_format_test_cases[] = {
 		KUNIT_CASE(iio_test_iio_format_value_fractional),
 		KUNIT_CASE(iio_test_iio_format_value_fractional_log2),
 		KUNIT_CASE(iio_test_iio_format_value_multiple),
+		KUNIT_CASE(iio_test_iio_format_value_char),
 		KUNIT_CASE(iio_test_iio_format_value_integer_64),
 		KUNIT_CASE(iio_test_iio_format_value_decimal_64),
 		{ }

---
base-commit: c9dbe2a47f635465c9985b7af74d2ae310e98125
change-id: 20261025-iio-test-format-char-8a17fbf9a201

Best regards,
--  
Raffaele Tranfaglia <raffaele.tranfaglia@gmail.com>

Re: [PATCH] iio: test: iio-test-format: add test case for char format

[Andy Shevchenko]

On Sun, Oct 25, 2026 at 04:59:41PM +0000, Raffaele Tranfaglia via B4 Relay wrote:
> From: Raffaele Tranfaglia <raffaele.tranfaglia@gmail.com>
> 
> IIO_VAL_CHAR is used by thermocouple drivers to report the
> thermocouple type, but iio_format_value() has no test for it.
> 
> Add a test case that checks a single character is printed followed
> by a newline.

> Assisted-by: LLM

Already outdated tag, please drop. Instead mention the AI usage in the comment
block (after '---' line).

> Signed-off-by: Raffaele Tranfaglia <raffaele.tranfaglia@gmail.com>

...

> +static void iio_test_iio_format_value_char(struct kunit *test)
> +{
> +	char *buf;
> +	int val;
> +	int ret;
> +
> +	buf = kunit_kmalloc(test, PAGE_SIZE, GFP_KERNEL);
> +	KUNIT_ASSERT_NOT_ERR_OR_NULL(test, buf);
> +
> +	val = 'K';
> +	ret = iio_format_value(buf, IIO_VAL_CHAR, 1, &val);
> +	IIO_TEST_FORMAT_EXPECT_EQ(test, buf, ret, "K\n");
> +
> +	val = 'j';
> +	ret = iio_format_value(buf, IIO_VAL_CHAR, 1, &val);
> +	IIO_TEST_FORMAT_EXPECT_EQ(test, buf, ret, "j\n");
> +
> +	val = '0';
> +	ret = iio_format_value(buf, IIO_VAL_CHAR, 1, &val);
> +	IIO_TEST_FORMAT_EXPECT_EQ(test, buf, ret, "0\n");
> +}

Add non-printable, special, et cetera test cases.
Make sure that IIO_TEST_FORMAT_EXPECT_EQ() check the entire buffer against
poison so we will know that iio_format_value() in the case of IIO_VAL_CHAR
doesn't write more than it is supposed to.

-- 
With Best Regards,
Andy Shevchenko