[PATCH 3/5] lib/tests: string_helpers: introduce test_string_unescape_one

[Jonas Rebmann <jre@pengutronix.de>]

The existing test_string_unescape() function follows a complex procedure
where it, given a set of UNESCAPE flags, appends multiple test fragments
and predicts their unescape result for the chosen set of flags. Rename
test_string_unescape() to a more descriptive
test_string_unescape_combined

In preparation to add simple regression tests, introduce
test_string_unescape_one() which asserts on exactly one call to
string_unescape.

Add some tests for corner cases which already pass.

Signed-off-by: Jonas Rebmann <jre@pengutronix.de>
---
 lib/tests/string_helpers_kunit.c | 31 +++++++++++++++++++++++++------
 1 file changed, 25 insertions(+), 6 deletions(-)

diff --git a/lib/tests/string_helpers_kunit.c b/lib/tests/string_helpers_kunit.c
index 1ed652f762d1..3c6fa7324965 100644
--- a/lib/tests/string_helpers_kunit.c
+++ b/lib/tests/string_helpers_kunit.c
@@ -55,9 +55,9 @@ static const struct test_string strings[] = {
 	},
 };
 
-static void test_string_unescape(struct kunit *test,
-				 const char *name, unsigned int flags,
-				 bool inplace)
+static void test_string_unescape_combined(struct kunit *test,
+					  const char *name, unsigned int flags,
+					  bool inplace)
 {
 	int q_real = 256;
 	char *in = kunit_kzalloc(test, q_real, GFP_KERNEL);
@@ -596,14 +596,33 @@ static void test_upper_lower(struct kunit *test)
 	}
 }
 
+static void test_string_unescape_one(struct kunit *test,
+				     const char *name, unsigned int flags,
+				     char *src, size_t len,
+				     char *out_test, size_t q_test)
+{
+	char *out_real = kunit_kzalloc(test, len, GFP_KERNEL);
+	int q_real;
+
+	q_real = string_unescape(src, out_real, len, flags);
+	test_string_check_buf(test, name, flags, out_real, q_real, out_test, q_test);
+}
+
 static void test_unescape(struct kunit *test)
 {
 	unsigned int i;
 
 	for (i = 0; i < UNESCAPE_ALL_MASK + 1; i++)
-		test_string_unescape(test, "unescape", i, false);
-	test_string_unescape(test, "unescape inplace",
-			     get_random_u32_below(UNESCAPE_ALL_MASK + 1), true);
+		test_string_unescape_combined(test, "unescape", i, false);
+	test_string_unescape_combined(test, "unescape inplace",
+				      get_random_u32_below(UNESCAPE_ALL_MASK + 1), true);
+
+	test_string_unescape_one(test, "simple case", UNESCAPE_HEX | UNESCAPE_SPECIAL, "ABC", 6, "ABC", 3);
+	test_string_unescape_one(test, "single escape", UNESCAPE_HEX | UNESCAPE_SPECIAL, "A\\x42C", 6, "ABC", 3);
+	test_string_unescape_one(test, "escape before end", UNESCAPE_HEX, "B\\qX", 4, "B\\q", 3);
+	test_string_unescape_one(test, "escape at end", UNESCAPE_HEX, "a\\qX", 3, "a\\", 2);
+	test_string_unescape_one(test, "backslash before escape", UNESCAPE_HEX, "\\\\x41B", 12, "\\\\x41B", 6);
+	test_string_unescape_one(test, "backslash escape", UNESCAPE_HEX | UNESCAPE_SPECIAL, "\\\\x41B", 16, "\\x41B", 5);
 }
 
 static void test_escape(struct kunit *test)

-- 
2.56.0.rc0.108.gf0ef1b96a0