軟件測試閲讀(中英文對照)

SOFTWARE TESTING

1．Purpose of Testing

　　No matter how capably we write programs，it is clear front the variety of possible errors that we should check to insure that our modules are coded correctly．Many programmers view testing as a demonstration that their programs perform properly．However，the idea of demonstrating correctness is really the reverse of what testing is all about．We test a program in order to demonstrate the existence of an error．Because our goal is to discover errors，we can consider a test successful only when an error is discovered．Once an error is found，“debugging”or error correction is the process of determining what causes the error and of making changes to the system so that the error no longer exists．

2．Stages of Testing

　　In the development of a large system，testing involves several stages．First，each program
module is tested as a single program，usually isolated from the other programs in the system．Such testing，known as module testing or unit-testing，verifies that the module functions properly with the types of input expected from studying the module design．Unit testing is done in a controlled environment whenever possible so that the test team can feed a predetermined set of data to the module being tested and observe what output data are produced[1]．In addition，the test team checks the internal data structures，the logic，and the boundary conditions for the input and output data．
　　When collections of modules have been unit-tested，the next step is to insure that the interfaces among the modules are defined and handled properly．Integration testing is the process of verifying that the components of a system work together as described in the program design and system design specifications．
　　Once we are sure that information is passed among modules according to the design prescriptions，we test the system to assure that it has the desired functionality．A function test evaluates the system to determine if the functions described by the requirements specification are actually performed by the integrated system [2]．The result，then，is a functioning system．
　　Recall that the requirements were specified in two ways：first in the customer’s terminology and again as a set of software and hardware requirements．The function test compares the system being built with the functions described in the software and hardware requirements．Then，a performance test compares the system with the remainder of the software and hardware requirements．If the test is performed in the customer’s actual working environment，a successful test yields a validated system．However，if the test must be performed in a simulated environment，the resulting system is a verified system．
　　When the performance test is complete，we as developers are certain that the system functions according to our understanding of the system description．The next step is to confer with the customer to make certain that the system works according to the customer’s expectations．We join with the customer to perform an acceptance test in which the system is checked against the customer’ s requirements description．When the acceptance test is complete，the accepted system is installed in the environment in which it will be used；a final installation test is performed to make sure that the system still functions as it should．
　　Fig. 8-2 illustrates the several stages of testing．Although systems may differ in size，the type of testing described in each stage is necessary for assuring the proper performance of any system being developed．
NOTES
　　[1] 從so that到句末爲so that引起的結果狀語從句，其中being tested爲被動語態現在
分詞作定語，脩飾module；動詞observe的賓語是what引起的從句。
　　[2] 從to determine到句末爲不定式短語作目的狀語，其中從if到句末爲determine的賓語從句，而該賓語從句中described by the requirements specification爲過去分詞短語作後置定語。

KEYWORDS
module testing 模塊測試
unit testing 單元測試
boundary condition 邊界條件
integration testing 綜郃測試，集成測試
function test 功能測試
performance test 性能測試
validated system 確認了的系統
verified system 經騐証的系統
acceptance test 騐收測試
debugging 調試
error correction 糾錯
installation test 安裝測試