kunit: Introduce KUNIT_EXPECT_MEMEQ and KUNIT_EXPECT_MEMNEQ macros

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>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

1 files changed, 56 insertions, 0 deletions

diff --git a/lib/kunit/assert.c b/lib/kunit/assert.c
index 24dec5b48722..f5b50babe38d 100644
--- a/lib/kunit/assert.c
+++ b/lib/kunit/assert.c
@@ -206,3 +206,59 @@ 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);