Tutorial

PDA software

In this tutorial we will test a small library that is used to maintain addresses of a PDA. The source code of the tutorial is stored in a tar ball and can be unpacked as follows:

$ mkdir tutorial
$ gzip -dc /usr/local/tutti/etc/tutorial.tgz | tar xvf -

A first test

A test driver which calls the functions of this library has already been developed. This is the file test_address.c. By invoking ``make'' we can build the test application and run it:

$ make
$ ./test_address

After execution, we see that the program issues some addresses to the screen. First we analyse the code with QAC:

$ make clean
$ make CC=qac_compiler
$ qac_scan
address.c,85:++ WARNING ++: <=8=(0179) Argument type does not match     conversion specifier number TEXT
address.c,170:++ WARNING ++: <=8=(0748) [U] 'TEXT()'    has a result type of 'int' but no 'return' statement    specifies an expression - the returned value is undefined.
address.c,195:++ WARNING ++: <=3=(3321) The variable    'TEXT' may be unset at this point.
address.c,203:++ WARNING ++: <=3=(3321) The variable    'TEXT' may be unset at this point.
address.c,219:++ WARNING ++: <=8=(0179) Argument type does not match    conversion specifier number TEXT
Verdict : fail

From the output we conclude that the code has some serious problems (although the code seems to behave correct!). In a `real-life'' software project it would be recommended to first solve these problems before continuing. We can analyse the dynamic behavior using insure as follows:

$ make clean
$ make CC=insure_compiler
$ ./test_address
$ insure_scan
address.c:28: LEAK_ASSIGN 
address.c:195: COPY_WILD 
address.c:195: READ_UNINIT_MEM(copy) 
address.c:12: LEAK_FREE 
VERDICT: Fail

The results indicate a few errors. With gcov we analyse the quality of the test design based upon code coverage:

$ make clean
$ make CC=gcov_compiler
$ ./test_address
$ gcov_scan
In file : address.c
                63% (statement) coverage
Verdict : fail

It can be conluded that only 63% statement coverage is achived by the current test.

Excersise

Try to improve the test design by investigation the coverage results (recorded in address.c.gcov) and by modifying the file test_address.c. The steps are outlined by figure 6.3 at page . Hereafter, check the dynamic behavior of the code using insure . The aim of this excersise is to obtain an effective test. It is not necessary to solve all defect you might encounter. Only solve a defect when it is a blocking error.