[PATCH v5 0/3] Introduce KUNIT_EXPECT_MEMEQ and KUNIT_EXPECT_MEMNEQ macros

[PATCH v5 0/3] Introduce KUNIT_EXPECT_MEMEQ and KUNIT_EXPECT_MEMNEQ macros

[Maíra Canal]

Currently, in order to compare memory blocks in KUnit, the KUNIT_EXPECT_EQ or
KUNIT_EXPECT_FALSE macros are used in conjunction with the memcmp function,
such as:
  KUNIT_EXPECT_EQ(test, memcmp(foo, bar, size), 0);

Although this usage produces correct results for the test cases, if the
expectation fails the error message is not very helpful, indicating only the
return of the memcmp function.

Therefore, create a new set of macros KUNIT_EXPECT_MEMEQ and
KUNIT_EXPECT_MEMNEQ that compare memory blocks until a determined size. In
case of expectation failure, those macros print the hex dump of the memory
blocks, making it easier to debug test failures for memory blocks.

The v5 doesn't have any new change, just rebasing on top of drm-misc-next.

The first patch of the series introduces the KUNIT_EXPECT_MEMEQ and
KUNIT_EXPECT_MEMNEQ. The second patch adds an example of memory block
expectations on the kunit-example-test.c. And the last patch replaces the
KUNIT_EXPECT_EQ for KUNIT_EXPECT_MEMEQ on the existing occurrences.

Best Regards,
- Maíra Canal

v1 -> v2: https://lore.kernel.org/linux-kselftest/2a0dcd75-5461-5266-2749-808f638f4c50@riseup.net/T/#m402cc72eb01fb3b88d6706cf7d1705fdd51e5da2

- Change "determinated" to "specified" (Daniel Latypov).
- Change the macro KUNIT_EXPECT_ARREQ to KUNIT_EXPECT_MEMEQ, in order to make
it easier for users to infer the right size unit (Daniel Latypov).
- Mark the different bytes on the failure message with a <> (Daniel Latypov).
- Replace a constant number of array elements for ARRAY_SIZE() (André Almeida).
- Rename "array" and "expected" variables to "array1" and "array2" (Daniel Latypov).

v2 -> v3: https://lore.kernel.org/linux-kselftest/20220802212621.420840-1-mairacanal@riseup.net/T/#t

- Make the bytes aligned at output.
- Add KUNIT_SUBSUBTEST_INDENT to the output for the indentation (Daniel Latypov).
- Line up the trailing \ at macros using tabs (Daniel Latypov).
- Line up the params to the functions (Daniel Latypov).
- Change "Increament" to "Augment" (Daniel Latypov).
- Use sizeof() for array sizes (Daniel Latypov).
- Add Daniel Latypov's tags.

v3 -> v4: https://lore.kernel.org/linux-kselftest/CABVgOSm_59Yr82deQm2C=18jjSv_akmn66zs4jxx3hfziXPeHg@mail.gmail.com/T/#t

- Fix wrapped lines by the mail client (David Gow).
- Mention on documentation that KUNIT_EXPECT_MEMEQ is not recommended for
structured data (David Gow).
- Add Muhammad Usama Anjum's tag.

v4 -> v5: https://lore.kernel.org/linux-kselftest/20220808125237.277126-1-mairacanal@riseup.net/

- Rebase on top of drm-misc-next.
- Add David Gow's tags.

Maíra Canal (3):
  kunit: Introduce KUNIT_EXPECT_MEMEQ and KUNIT_EXPECT_MEMNEQ macros
  kunit: Add KUnit memory block assertions to the
    example_all_expect_macros_test
  kunit: Use KUNIT_EXPECT_MEMEQ macro

 .../gpu/drm/tests/drm_format_helper_test.c    |  6 +-
 include/kunit/assert.h                        | 34 ++++++++
 include/kunit/test.h                          | 84 +++++++++++++++++++
 lib/kunit/assert.c                            | 56 +++++++++++++
 lib/kunit/kunit-example-test.c                |  7 ++
 net/core/dev_addr_lists_test.c                |  4 +-
 6 files changed, 186 insertions(+), 5 deletions(-)

-- 
2.37.3

[PATCH v5 1/3] kunit: Introduce KUNIT_EXPECT_MEMEQ and KUNIT_EXPECT_MEMNEQ macros

[Maíra Canal]

Currently, in order to compare memory blocks in KUnit, the KUNIT_EXPECT_EQ
or KUNIT_EXPECT_FALSE macros are used in conjunction with the memcmp
function, such as:
    KUNIT_EXPECT_EQ(test, memcmp(foo, bar, size), 0);

Although this usage produces correct results for the test cases, when
the expectation fails, the error message is not very helpful,
indicating only the return of the memcmp function.

Therefore, create a new set of macros KUNIT_EXPECT_MEMEQ and
KUNIT_EXPECT_MEMNEQ that compare memory blocks until a specified size.
In case of expectation failure, those macros print the hex dump of the
memory blocks, making it easier to debug test failures for memory blocks.

That said, the expectation

    KUNIT_EXPECT_EQ(test, memcmp(foo, bar, size), 0);

would translate to the expectation

    KUNIT_EXPECT_MEMEQ(test, foo, bar, size);

Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Reviewed-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Reviewed-by: David Gow <davidgow@google.com>
---
 include/kunit/assert.h | 34 +++++++++++++++++
 include/kunit/test.h   | 84 ++++++++++++++++++++++++++++++++++++++++++
 lib/kunit/assert.c     | 56 ++++++++++++++++++++++++++++
 3 files changed, 174 insertions(+)

diff --git a/include/kunit/assert.h b/include/kunit/assert.h
index 4b52e12c2ae8..4b817a8eb619 100644
--- a/include/kunit/assert.h
+++ b/include/kunit/assert.h
@@ -256,4 +256,38 @@ void kunit_binary_str_assert_format(const struct kunit_assert *assert,
 				    const struct va_format *message,
 				    struct string_stream *stream);
 
+#define KUNIT_INIT_MEM_ASSERT_STRUCT(text_, left_val, right_val, size_)   \
+	{                                                                 \
+		.assert = { .format = kunit_mem_assert_format },          \
+		.text = text_,                                            \
+		.left_value = left_val,                                   \
+		.right_value = right_val, .size = size_,                  \
+	}
+
+/**
+ * struct kunit_mem_assert - An expectation/assertion that compares two
+ *	memory blocks.
+ * @assert: The parent of this type.
+ * @text: Holds the textual representations of the operands and comparator.
+ * @left_value: The actual evaluated value of the expression in the left slot.
+ * @right_value: The actual evaluated value of the expression in the right slot.
+ * @size: Size of the memory block analysed in bytes.
+ *
+ * Represents an expectation/assertion that compares two memory blocks. For
+ * example, to expect that the first three bytes of foo is equal to the
+ * first three bytes of bar, you can use the expectation
+ * KUNIT_EXPECT_MEMEQ(test, foo, bar, 3);
+ */
+struct kunit_mem_assert {
+	struct kunit_assert assert;
+	const struct kunit_binary_assert_text *text;
+	const void *left_value;
+	const void *right_value;
+	const size_t size;
+};
+
+void kunit_mem_assert_format(const struct kunit_assert *assert,
+			     const struct va_format *message,
+			     struct string_stream *stream);
+
 #endif /*  _KUNIT_ASSERT_H */
diff --git a/include/kunit/test.h b/include/kunit/test.h
index c958855681cc..d384d61e7f11 100644
--- a/include/kunit/test.h
+++ b/include/kunit/test.h
@@ -647,6 +647,36 @@ do {									       \
 			##__VA_ARGS__);					       \
 } while (0)
 
+#define KUNIT_MEM_ASSERTION(test,					       \
+			    assert_type,				       \
+			    left,					       \
+			    op,						       \
+			    right,					       \
+			    size,					       \
+			    fmt,					       \
+			    ...)					       \
+do {									       \
+	const void *__left = (left);					       \
+	const void *__right = (right);					       \
+	const size_t __size = (size);					       \
+	static const struct kunit_binary_assert_text __text = {		       \
+		.operation = #op,					       \
+		.left_text = #left,					       \
+		.right_text = #right,					       \
+	};								       \
+									       \
+	KUNIT_ASSERTION(test,						       \
+			assert_type,					       \
+			memcmp(__left, __right, __size) op 0,		       \
+			kunit_mem_assert,				       \
+			KUNIT_INIT_MEM_ASSERT_STRUCT(&__text,		       \
+						     __left,		       \
+						     __right,		       \
+						     __size),		       \
+			fmt,						       \
+			##__VA_ARGS__);					       \
+} while (0)
+
 #define KUNIT_PTR_NOT_ERR_OR_NULL_MSG_ASSERTION(test,			       \
 						assert_type,		       \
 						ptr,			       \
@@ -915,6 +945,60 @@ do {									       \
 				   fmt,					       \
 				   ##__VA_ARGS__)
 
+/**
+ * KUNIT_EXPECT_MEMEQ() - Expects that the first @size bytes of @left and @right are equal.
+ * @test: The test context object.
+ * @left: An arbitrary expression that evaluates to the specified size.
+ * @right: An arbitrary expression that evaluates to the specified size.
+ * @size: Number of bytes compared.
+ *
+ * Sets an expectation that the values that @left and @right evaluate to are
+ * equal. This is semantically equivalent to
+ * KUNIT_EXPECT_TRUE(@test, !memcmp((@left), (@right), (@size))). See
+ * KUNIT_EXPECT_TRUE() for more information.
+ *
+ * Although this expectation works for any memory block, it is not recommended
+ * for comparing more structured data, such as structs. This expectation is
+ * recommended for comparing, for example, data arrays.
+ */
+#define KUNIT_EXPECT_MEMEQ(test, left, right, size) \
+	KUNIT_EXPECT_MEMEQ_MSG(test, left, right, size, NULL)
+
+#define KUNIT_EXPECT_MEMEQ_MSG(test, left, right, size, fmt, ...)	       \
+	KUNIT_MEM_ASSERTION(test,					       \
+			    KUNIT_EXPECTATION,				       \
+			    left, ==, right,				       \
+			    size,					       \
+			    fmt,					       \
+			    ##__VA_ARGS__)
+
+/**
+ * KUNIT_EXPECT_MEMNEQ() - Expects that the first @size bytes of @left and @right are not equal.
+ * @test: The test context object.
+ * @left: An arbitrary expression that evaluates to the specified size.
+ * @right: An arbitrary expression that evaluates to the specified size.
+ * @size: Number of bytes compared.
+ *
+ * Sets an expectation that the values that @left and @right evaluate to are
+ * not equal. This is semantically equivalent to
+ * KUNIT_EXPECT_TRUE(@test, memcmp((@left), (@right), (@size))). See
+ * KUNIT_EXPECT_TRUE() for more information.
+ *
+ * Although this expectation works for any memory block, it is not recommended
+ * for comparing more structured data, such as structs. This expectation is
+ * recommended for comparing, for example, data arrays.
+ */
+#define KUNIT_EXPECT_MEMNEQ(test, left, right, size) \
+	KUNIT_EXPECT_MEMNEQ_MSG(test, left, right, size, NULL)
+
+#define KUNIT_EXPECT_MEMNEQ_MSG(test, left, right, size, fmt, ...)	       \
+	KUNIT_MEM_ASSERTION(test,					       \
+			    KUNIT_EXPECTATION,				       \
+			    left, !=, right,				       \
+			    size,					       \
+			    fmt,					       \
+			    ##__VA_ARGS__)
+
 /**
  * KUNIT_EXPECT_NULL() - Expects that @ptr is null.
  * @test: The test context object.
diff --git a/lib/kunit/assert.c b/lib/kunit/assert.c
index d00d6d181ee8..c346a8d7fa6e 100644
--- a/lib/kunit/assert.c
+++ b/lib/kunit/assert.c
@@ -204,3 +204,59 @@ void kunit_binary_str_assert_format(const struct kunit_assert *assert,
 	kunit_assert_print_msg(message, stream);
 }
 EXPORT_SYMBOL_GPL(kunit_binary_str_assert_format);
+
+/* Adds a hexdump of a buffer to a string_stream comparing it with
+ * a second buffer. The different bytes are marked with <>.
+ */
+static void kunit_assert_hexdump(struct string_stream *stream,
+				 const void *buf,
+				 const void *compared_buf,
+				 const size_t len)
+{
+	size_t i;
+	const u8 *buf1 = buf;
+	const u8 *buf2 = compared_buf;
+
+	string_stream_add(stream, KUNIT_SUBSUBTEST_INDENT);
+
+	for (i = 0; i < len; ++i) {
+		if (!(i % 16) && i)
+			string_stream_add(stream, "\n" KUNIT_SUBSUBTEST_INDENT);
+
+		if (buf1[i] != buf2[i])
+			string_stream_add(stream, "<%02x>", buf1[i]);
+		else
+			string_stream_add(stream, " %02x ", buf1[i]);
+	}
+}
+
+void kunit_mem_assert_format(const struct kunit_assert *assert,
+			     const struct va_format *message,
+			     struct string_stream *stream)
+{
+	struct kunit_mem_assert *mem_assert;
+
+	mem_assert = container_of(assert, struct kunit_mem_assert,
+				  assert);
+
+	string_stream_add(stream,
+			  KUNIT_SUBTEST_INDENT "Expected %s %s %s, but\n",
+			  mem_assert->text->left_text,
+			  mem_assert->text->operation,
+			  mem_assert->text->right_text);
+
+	string_stream_add(stream, KUNIT_SUBSUBTEST_INDENT "%s ==\n",
+			  mem_assert->text->left_text);
+	kunit_assert_hexdump(stream, mem_assert->left_value,
+			     mem_assert->right_value, mem_assert->size);
+
+	string_stream_add(stream, "\n");
+
+	string_stream_add(stream, KUNIT_SUBSUBTEST_INDENT "%s ==\n",
+			  mem_assert->text->right_text);
+	kunit_assert_hexdump(stream, mem_assert->right_value,
+			     mem_assert->left_value, mem_assert->size);
+
+	kunit_assert_print_msg(message, stream);
+}
+EXPORT_SYMBOL_GPL(kunit_mem_assert_format);
-- 
2.37.3

[PATCH v5 2/3] kunit: Add KUnit memory block assertions to the example_all_expect_macros_test

[Maíra Canal]

Augment the example_all_expect_macros_test with the KUNIT_EXPECT_MEMEQ
and KUNIT_EXPECT_MEMNEQ macros by creating a test with memory block
assertions.

Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Reviewed-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: David Gow <davidgow@google.com>
---
 lib/kunit/kunit-example-test.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/lib/kunit/kunit-example-test.c b/lib/kunit/kunit-example-test.c
index f8fe582c9e36..66cc4e2365ec 100644
--- a/lib/kunit/kunit-example-test.c
+++ b/lib/kunit/kunit-example-test.c
@@ -86,6 +86,9 @@ static void example_mark_skipped_test(struct kunit *test)
  */
 static void example_all_expect_macros_test(struct kunit *test)
 {
+	const u32 array1[] = { 0x0F, 0xFF };
+	const u32 array2[] = { 0x1F, 0xFF };
+
 	/* Boolean assertions */
 	KUNIT_EXPECT_TRUE(test, true);
 	KUNIT_EXPECT_FALSE(test, false);
@@ -109,6 +112,10 @@ static void example_all_expect_macros_test(struct kunit *test)
 	KUNIT_EXPECT_STREQ(test, "hi", "hi");
 	KUNIT_EXPECT_STRNEQ(test, "hi", "bye");
 
+	/* Memory block assertions */
+	KUNIT_EXPECT_MEMEQ(test, array1, array1, sizeof(array1));
+	KUNIT_EXPECT_MEMNEQ(test, array1, array2, sizeof(array1));
+
 	/*
 	 * There are also ASSERT variants of all of the above that abort test
 	 * execution if they fail. Useful for memory allocations, etc.
-- 
2.37.3

[PATCH v5 3/3] kunit: Use KUNIT_EXPECT_MEMEQ macro

[Maíra Canal]

Use KUNIT_EXPECT_MEMEQ to compare memory blocks in replacement of the
KUNIT_EXPECT_EQ macro. Therefor, the statement

    KUNIT_EXPECT_EQ(test, memcmp(foo, bar, size), 0);

is replaced by:

    KUNIT_EXPECT_MEMEQ(test, foo, bar, size);

Signed-off-by: Maíra Canal <mairacanal@riseup.net>
Acked-by: Daniel Latypov <dlatypov@google.com>
Reviewed-by: David Gow <davidgow@google.com>
---
 drivers/gpu/drm/tests/drm_format_helper_test.c | 6 +++---
 net/core/dev_addr_lists_test.c                 | 4 ++--
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/tests/drm_format_helper_test.c b/drivers/gpu/drm/tests/drm_format_helper_test.c
index ab49f5e8796c..e2746429ea3e 100644
--- a/drivers/gpu/drm/tests/drm_format_helper_test.c
+++ b/drivers/gpu/drm/tests/drm_format_helper_test.c
@@ -219,7 +219,7 @@ static void drm_test_fb_xrgb8888_to_rgb332(struct kunit *test)
 	iosys_map_set_vaddr(&src, xrgb8888);
 
 	drm_fb_xrgb8888_to_rgb332(&dst, &result->dst_pitch, &src, &fb, &params->clip);
-	KUNIT_EXPECT_EQ(test, memcmp(buf, result->expected, dst_size), 0);
+	KUNIT_EXPECT_MEMEQ(test, buf, result->expected, dst_size);
 }
 
 static void drm_test_fb_xrgb8888_to_rgb565(struct kunit *test)
@@ -249,10 +249,10 @@ static void drm_test_fb_xrgb8888_to_rgb565(struct kunit *test)
 	iosys_map_set_vaddr(&src, xrgb8888);
 
 	drm_fb_xrgb8888_to_rgb565(&dst, &result->dst_pitch, &src, &fb, &params->clip, false);
-	KUNIT_EXPECT_EQ(test, memcmp(buf, result->expected, dst_size), 0);
+	KUNIT_EXPECT_MEMEQ(test, buf, result->expected, dst_size);
 
 	drm_fb_xrgb8888_to_rgb565(&dst, &result->dst_pitch, &src, &fb, &params->clip, true);
-	KUNIT_EXPECT_EQ(test, memcmp(buf, result->expected_swab, dst_size), 0);
+	KUNIT_EXPECT_MEMEQ(test, buf, result->expected_swab, dst_size);
 }
 
 static struct kunit_case drm_format_helper_test_cases[] = {
diff --git a/net/core/dev_addr_lists_test.c b/net/core/dev_addr_lists_test.c
index 049cfbc58aa9..90e7e3811ae7 100644
--- a/net/core/dev_addr_lists_test.c
+++ b/net/core/dev_addr_lists_test.c
@@ -71,11 +71,11 @@ static void dev_addr_test_basic(struct kunit *test)
 
 	memset(addr, 2, sizeof(addr));
 	eth_hw_addr_set(netdev, addr);
-	KUNIT_EXPECT_EQ(test, 0, memcmp(netdev->dev_addr, addr, sizeof(addr)));
+	KUNIT_EXPECT_MEMEQ(test, netdev->dev_addr, addr, sizeof(addr));
 
 	memset(addr, 3, sizeof(addr));
 	dev_addr_set(netdev, addr);
-	KUNIT_EXPECT_EQ(test, 0, memcmp(netdev->dev_addr, addr, sizeof(addr)));
+	KUNIT_EXPECT_MEMEQ(test, netdev->dev_addr, addr, sizeof(addr));
 }
 
 static void dev_addr_test_sync_one(struct kunit *test)
-- 
2.37.3