diff --git a/mysql-test/r/variables.result b/mysql-test/r/variables.result
index 376a8ffa38e..04ccf3d688c 100644
--- a/mysql-test/r/variables.result
+++ b/mysql-test/r/variables.result
@@ -236,32 +236,66 @@ set @@rand_seed1=10000000,@@rand_seed2=1000000;
 select ROUND(RAND(),5);
 ROUND(RAND(),5)
 0.02887
-show variables like '%alloc%';
+
+==+ Testing %alloc% system variables +==
+==+ NOTE:  These values *must* be a multiple of 1024 +==
+==+ Other values will be rounded down to nearest multiple +==
+
+==+ Show initial values +==
+SHOW VARIABLES WHERE variable_name IN ('range_alloc_block_size',
+'query_alloc_block_size', 'query_prealloc_size',
+'transaction_alloc_block_size', 'transaction_prealloc_size');
 Variable_name	Value
 query_alloc_block_size	8192
 query_prealloc_size	8192
 range_alloc_block_size	4096
 transaction_alloc_block_size	8192
 transaction_prealloc_size	4096
-set @@range_alloc_block_size=1024*16;
+==+ Manipulate variable values +=
+Testing values that are multiples of 1024
+set @@range_alloc_block_size=1024*15+1024;
+set @@query_alloc_block_size=1024*15+1024*2;
+set @@query_prealloc_size=1024*18-1024;
+set @@transaction_alloc_block_size=1024*21-1024*1;
+set @@transaction_prealloc_size=1024*21-2048;
+==+ Check manipulated values ==+
+SHOW VARIABLES WHERE variable_name IN ('range_alloc_block_size',
+'query_alloc_block_size', 'query_prealloc_size',
+'transaction_alloc_block_size', 'transaction_prealloc_size');
+Variable_name	Value
+query_alloc_block_size	17408
+query_prealloc_size	17408
+range_alloc_block_size	16384
+transaction_alloc_block_size	20480
+transaction_prealloc_size	19456
+==+ Manipulate variable values +==
+Testing values that are not 1024 multiples
+set @@range_alloc_block_size=1024*16+1023;
 set @@query_alloc_block_size=1024*17+2;
-set @@query_prealloc_size=1024*18;
+set @@query_prealloc_size=1024*18-1023;
 set @@transaction_alloc_block_size=1024*20-1;
 set @@transaction_prealloc_size=1024*21-1;
 select @@query_alloc_block_size;
 @@query_alloc_block_size
 17408
-show variables like '%alloc%';
+==+ Check manipulated values ==+
+SHOW VARIABLES WHERE variable_name IN ('range_alloc_block_size',
+'query_alloc_block_size', 'query_prealloc_size',
+'transaction_alloc_block_size', 'transaction_prealloc_size');
 Variable_name	Value
 query_alloc_block_size	17408
-query_prealloc_size	18432
+query_prealloc_size	17408
 range_alloc_block_size	16384
 transaction_alloc_block_size	19456
 transaction_prealloc_size	20480
+==+ Set values back to the default values +==
 set @@range_alloc_block_size=default;
 set @@query_alloc_block_size=default, @@query_prealloc_size=default;
 set transaction_alloc_block_size=default, @@transaction_prealloc_size=default;
-show variables like '%alloc%';
+==+ Check the values not that they are reset +==
+SHOW VARIABLES WHERE variable_name IN ('range_alloc_block_size',
+'query_alloc_block_size', 'query_prealloc_size',
+'transaction_alloc_block_size', 'transaction_prealloc_size');
 Variable_name	Value
 query_alloc_block_size	8192
 query_prealloc_size	8192
diff --git a/mysql-test/t/variables.test b/mysql-test/t/variables.test
index 60254ad9a1d..173be9d87c6 100644
--- a/mysql-test/t/variables.test
+++ b/mysql-test/t/variables.test
@@ -150,18 +150,46 @@ select @@timestamp>0;
 set @@rand_seed1=10000000,@@rand_seed2=1000000;
 select ROUND(RAND(),5);
 
-show variables like '%alloc%';
-set @@range_alloc_block_size=1024*16;
+--echo
+--echo ==+ Testing %alloc% system variables +==
+--echo ==+ NOTE:  These values *must* be a multiple of 1024 +==
+--echo ==+ Other values will be rounded down to nearest multiple +==
+--echo
+--echo ==+ Show initial values +==
+SHOW VARIABLES WHERE variable_name IN ('range_alloc_block_size',
+'query_alloc_block_size', 'query_prealloc_size',
+'transaction_alloc_block_size', 'transaction_prealloc_size');
+--echo ==+ Manipulate variable values +=
+--echo Testing values that are multiples of 1024
+set @@range_alloc_block_size=1024*15+1024;
+set @@query_alloc_block_size=1024*15+1024*2;
+set @@query_prealloc_size=1024*18-1024;
+set @@transaction_alloc_block_size=1024*21-1024*1;
+set @@transaction_prealloc_size=1024*21-2048;
+--echo ==+ Check manipulated values ==+
+SHOW VARIABLES WHERE variable_name IN ('range_alloc_block_size',
+'query_alloc_block_size', 'query_prealloc_size',
+'transaction_alloc_block_size', 'transaction_prealloc_size');
+--echo ==+ Manipulate variable values +==
+--echo Testing values that are not 1024 multiples
+set @@range_alloc_block_size=1024*16+1023;
 set @@query_alloc_block_size=1024*17+2;
-set @@query_prealloc_size=1024*18;
+set @@query_prealloc_size=1024*18-1023;
 set @@transaction_alloc_block_size=1024*20-1;
 set @@transaction_prealloc_size=1024*21-1;
 select @@query_alloc_block_size;
-show variables like '%alloc%';
+--echo ==+ Check manipulated values ==+
+SHOW VARIABLES WHERE variable_name IN ('range_alloc_block_size',
+'query_alloc_block_size', 'query_prealloc_size',
+'transaction_alloc_block_size', 'transaction_prealloc_size');
+--echo ==+ Set values back to the default values +==
 set @@range_alloc_block_size=default;
 set @@query_alloc_block_size=default, @@query_prealloc_size=default;
 set transaction_alloc_block_size=default, @@transaction_prealloc_size=default;
-show variables like '%alloc%';
+--echo ==+ Check the values not that they are reset +==
+SHOW VARIABLES WHERE variable_name IN ('range_alloc_block_size',
+'query_alloc_block_size', 'query_prealloc_size',
+'transaction_alloc_block_size', 'transaction_prealloc_size');
 
 #
 # Bug #10904 Illegal mix of collations between