Pair Testing

All-Pairs Testing is a test design method to deal with the combinatorics problem of defining test cases in a systematic way.

成对组合覆盖这一概念是Mandl于1985年在测试Aad编译程序时提出来的。Cohen等人应用成对组合覆盖测试技术对Unix中的“Sort”命令进行了测试。测试结果表明覆盖率高达90%以上。可见成对组合覆盖是一种非常有效的测试用例设计方法。 成对组合覆盖要求任意两个因素（输入条件）的所有水平组合至少要被覆盖1次。组合覆盖的算法已经被很多工具实现，测试人员可以直接利用这些工具，例如：TConfig、微软的PICT等。下面介绍一下使用PICT设计测试用例的过程。 

PICT，全称是Pairwise Independent Combinatorial Testing tool，是微软公司内部使用的一款成对组合的命令行生成工具，现在已经对外提供，可以从

官网：http://www.pairwise.org/ 常用的Pairwise工具集：http://www.pairwise.org/tools.asp上下载到。

PICT工具原理和算法实现可以参考http://msdn.microsoft.com/en-us/library/cc150619.aspx

 

model.txt

 

• The model defines the parameters that need to be 'combined' and their values.
• Parameter names and values are defined by "parmname: val1, val2, ..." (list of comma seprated values).
• Values can be any string (numbers, names, logical names like "empty")
• You can define constraints to make sure the tool does not generate test case variants that are illegal.
• For details see  PICT language reference
  #

  # PICT Example model: Parameters to the windows 'FORMAT' command

  #

   

  Type: Primary, Logical, Single, Span, Stripe, Mirror, RAID-5

  Size: 10, 100, 500, 1000, 5000, 10000, 40000

  Format method: quick, slow

  File system: FAT, FAT32, NTFS

  Cluster size: 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536

  Compression: on, off

   

  # some simple constraints

  IF [File system] = "FAT" THEN [Size] <= 4096;

  IF [File system] = "FAT32" THEN [Size] <= 32000;

   

   

   

  The number of test cases produced by different tools for the same model:

  Model	AETG 1)	IPO 2)	TConfig 3)	CTS 4)	Jenny 5)	TestCover 6)	DDA 7)	AllPairs [McDowell] 5)	PICT	EXACT8)	IPO-s 9)	ecFeed 10)
  34	9	9	9	9	11	9	?	9	9	9	9	10
  313	15	17	15	15	18	15	18	17	18	15	17	19
  415 317 229	41	34	40	39	38	29	35	34	37	?	32	37
  41 339 235	28	26	30	29	28	21	27	26	27	21	23	28
  2100	10	15	14	10	16	10	15	14	15	10	10	16
  1020	180	212	231	210	193	181	201	197	210	?	220	203