diff --git a/tools/testing/memblock/tests/basic_api.c b/tools/testing/memblock/tests/basic_api.c
index cdf112d25343..834d8705ff8a 100644
--- a/tools/testing/memblock/tests/basic_api.c
+++ b/tools/testing/memblock/tests/basic_api.c
@@ -306,8 +306,8 @@ static int memblock_add_checks(void)
  /*
   * A simple test that marks a memory block of a specified base address
   * and size as reserved and to the collection of reserved memory regions
-  * (memblock.reserved). It checks if a new entry was created and if region
-  * counter and total memory size were correctly updated.
+  * (memblock.reserved). Expect to create a new entry. The region counter
+  * and total memory size are updated.
   */
 static int memblock_reserve_simple_check(void)
 {
@@ -330,10 +330,15 @@ static int memblock_reserve_simple_check(void)
 }
 
 /*
- * A test that tries to mark two memory blocks that don't overlap as reserved
- * and checks if two entries were correctly added to the collection of reserved
- * memory regions (memblock.reserved) and if this change was reflected in
- * memblock.reserved's total size and region counter.
+ * A test that tries to mark two memory blocks that don't overlap as reserved:
+ *
+ *  |        +--+      +----------------+  |
+ *  |        |r1|      |       r2       |  |
+ *  +--------+--+------+----------------+--+
+ *
+ * Expect to add two entries to the collection of reserved memory regions
+ * (memblock.reserved). The total size and region counter for
+ * memblock.reserved are updated.
  */
 static int memblock_reserve_disjoint_check(void)
 {
@@ -370,11 +375,20 @@ static int memblock_reserve_disjoint_check(void)
 /*
  * A test that tries to mark two memory blocks as reserved, where the
  * second one overlaps with the beginning of the first (that is
- * r1.base < r2.base + r2.size).
- * It checks if two entries are merged into one region that starts at r2.base
- * and has size of two regions minus their intersection. The test also verifies
- * that memblock can still see only one entry and has a correct total size of
- * the reserved memory.
+ * r1.base < r2.base + r2.size):
+ *
+ *  |  +--------------+--+--------------+  |
+ *  |  |       r2     |  |     r1       |  |
+ *  +--+--------------+--+--------------+--+
+ *     ^              ^
+ *     |              |
+ *     |              r1.base
+ *     |
+ *     r2.base
+ *
+ * Expect to merge two entries into one region that starts at r2.base and
+ * has size of two regions minus their intersection. The total size of the
+ * reserved memory is updated, and the region counter is not updated.
  */
 static int memblock_reserve_overlap_top_check(void)
 {
@@ -411,10 +425,19 @@ static int memblock_reserve_overlap_top_check(void)
  * A test that tries to mark two memory blocks as reserved, where the
  * second one overlaps with the end of the first entry (that is
  * r2.base < r1.base + r1.size).
- * It checks if two entries are merged into one region that starts at r1.base
- * and has size of two regions minus their intersection. It verifies that
- * memblock can still see only one entry and has a correct total size of the
- * reserved memory.
+ *
+ *  |  +--------------+--+--------------+  |
+ *  |  |       r1     |  |     r2       |  |
+ *  +--+--------------+--+--------------+--+
+ *     ^              ^
+ *     |              |
+ *     |              r2.base
+ *     |
+ *     r1.base
+ *
+ * Expect to merge two entries into one region that starts at r1.base and
+ * has size of two regions minus their intersection. The total size of the
+ * reserved memory is updated, and the region counter is not updated.
  */
 static int memblock_reserve_overlap_bottom_check(void)
 {
@@ -451,9 +474,18 @@ static int memblock_reserve_overlap_bottom_check(void)
  * A test that tries to mark two memory blocks as reserved, where the second
  * one is within the range of the first entry (that is
  * (r1.base < r2.base) && (r2.base + r2.size < r1.base + r1.size)).
- * It checks if two entries are merged into one region that stays the
- * same. The counter and total size of available memory are expected to not be
- * updated.
+ *
+ *  | +-----+--+---------------------------|
+ *  | |     |r2|          r1               |
+ *  +-+-----+--+---------------------------+
+ *    ^     ^
+ *    |     |
+ *    |     r2.base
+ *    |
+ *    r1.base
+ *
+ * Expect to merge two entries into one region that stays the same. The
+ * counter and total size of available memory are not updated.
  */
 static int memblock_reserve_within_check(void)
 {
@@ -485,7 +517,7 @@ static int memblock_reserve_within_check(void)
 
 /*
  * A simple test that tries to reserve the same memory block twice.
- * The region counter and total size of reserved memory are expected to not
+ * Expect the region counter and total size of reserved memory to not
  * be updated.
  */
 static int memblock_reserve_twice_check(void)
