212 lines
6.9 KiB
Plaintext
212 lines
6.9 KiB
Plaintext
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HOW TO USE
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You can use CuTest to create unit tests to drive your development
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in the style of Extreme Programming. You can also add unit tests to
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existing code to ensure that it works as you suspect.
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Your unit tests are an investment. They let you to change your
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code and add new features confidently without worrying about
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accidentally breaking earlier features.
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LICENSING
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For details on licensing see license.txt.
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GETTING STARTED
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To add unit testing to your C code the only files you need are
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CuTest.c and CuTest.h.
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CuTestTest.c and AllTests.c have been included to provide an
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example of how to write unit tests and then how to aggregate them
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into suites and into a single AllTests.c file. Suites allow you
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to put group tests into logical sets. AllTests.c combines all the
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suites and runs them.
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You should not have to look inside CuTest.c. Looking in
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CuTestTest.c and AllTests.c (for example usage) should be
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sufficient.
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After downloading the sources, run your compiler to create an
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executable called AllTests.exe. For example, if you are using
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Windows with the cl.exe compiler you would type:
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cl.exe AllTests.c CuTest.c CuTestTest.c
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AllTests.exe
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This will run all the unit tests associated with CuTest and print
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the output on the console. You can replace cl.exe with gcc or
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your favorite compiler in the command above.
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DETAILED EXAMPLE
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Here is a more detailed example. We will work through a simple
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test first exercise. The goal is to create a library of string
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utilities. First, lets write a function that converts a
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null-terminated string to all upper case.
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Ensure that CuTest.c and CuTest.h are accessible from your C
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project. Next, create a file called StrUtil.c with these
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contents:
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#include "CuTest.h"
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char* StrToUpper(char* str) {
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return str;
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}
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void TestStrToUpper(CuTest *tc) {
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char* input = strdup("hello world");
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char* actual = StrToUpper(input);
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char* expected = "HELLO WORLD";
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CuAssertStrEquals(tc, expected, actual);
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}
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CuSuite* StrUtilGetSuite() {
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CuSuite* suite = CuSuiteNew();
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SUITE_ADD_TEST(suite, TestStrToUpper);
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return suite;
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}
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Create another file called AllTests.c with these contents:
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#include "CuTest.h"
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CuSuite* StrUtilGetSuite();
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void RunAllTests(void) {
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CuString *output = CuStringNew();
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CuSuite* suite = CuSuiteNew();
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CuSuiteAddSuite(suite, StrUtilGetSuite());
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CuSuiteRun(suite);
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CuSuiteSummary(suite, output);
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CuSuiteDetails(suite, output);
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printf("%s\n", output->buffer);
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}
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int main(void) {
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RunAllTests();
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}
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Then type this on the command line:
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gcc AllTests.c CuTest.c StrUtil.c
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to compile. You can replace gcc with your favorite compiler.
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CuTest should be portable enough to handle all Windows and Unix
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compilers. Then to run the tests type:
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a.out
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This will print an error because we haven't implemented the
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StrToUpper function correctly. We are just returning the string
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without changing it to upper case.
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char* StrToUpper(char* str) {
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return str;
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}
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Rewrite this as follows:
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char* StrToUpper(char* str) {
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char* p;
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for (p = str ; *p ; ++p) *p = toupper(*p);
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return str;
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}
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Recompile and run the tests again. The test should pass this
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time.
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WHAT TO DO NEXT
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At this point you might want to write more tests for the
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StrToUpper function. Here are some ideas:
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TestStrToUpper_EmptyString : pass in ""
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TestStrToUpper_UpperCase : pass in "HELLO WORLD"
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TestStrToUpper_MixedCase : pass in "HELLO world"
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TestStrToUpper_Numbers : pass in "1234 hello"
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As you write each one of these tests add it to StrUtilGetSuite
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function. If you don't the tests won't be run. Later as you write
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other functions and write tests for them be sure to include those
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in StrUtilGetSuite also. The StrUtilGetSuite function should
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include all the tests in StrUtil.c
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Over time you will create another file called FunkyStuff.c
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containing other functions unrelated to StrUtil. Follow the same
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pattern. Create a FunkyStuffGetSuite function in FunkyStuff.c.
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And add FunkyStuffGetSuite to AllTests.c.
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The framework is designed in the way it is so that it is easy to
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organize a lot of tests.
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THE BIG PICTURE
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Each individual test corresponds to a CuTest. These are grouped
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to form a CuSuite. CuSuites can hold CuTests or other CuSuites.
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AllTests.c collects all the CuSuites in the program into a single
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CuSuite which it then runs as a single CuSuite.
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The project is open source so feel free to take a peek under the
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hood at the CuTest.c file to see how it works. CuTestTest.c
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contains tests for CuTest.c. So CuTest tests itself.
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Since AllTests.c has a main() you will need to exclude this when
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you are building your product. Here is a nicer way to do this if
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you want to avoid messing with multiple builds. Remove the main()
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in AllTests.c. Note that it just calls RunAllTests(). Instead
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we'll call this directly from the main program.
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Now in the main() of the actual program check to see if the
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command line option "--test" was passed. If it was then I call
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RunAllTests() from AllTests.c. Otherwise run the real program.
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Shipping the tests with the code can be useful. If you customers
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complain about a problem you can ask them to run the unit tests
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and send you the output. This can help you to quickly isolate the
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piece of your system that is malfunctioning in the customer's
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environment.
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CuTest offers a rich set of CuAssert functions. Here is a list:
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void CuAssert(CuTest* tc, char* message, int condition);
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void CuAssertTrue(CuTest* tc, int condition);
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void CuAssertStrEquals(CuTest* tc, char* expected, char* actual);
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void CuAssertIntEquals(CuTest* tc, int expected, int actual);
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void CuAssertPtrEquals(CuTest* tc, void* expected, void* actual);
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void CuAssertPtrNotNull(CuTest* tc, void* pointer);
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The project is open source and so you can add other more powerful
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asserts to make your tests easier to write and more concise.
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Please feel free to send me changes you make so that I can
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incorporate them into future releases.
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If you see any errors in this document please contact me at
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asimjalis@peakprogramming.com.
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AUTOMATING TEST SUITE GENERATION
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make-tests.sh will grep through all the .c files in the current
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directory and generate the code to run all the tests contained in
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them. Using this script you don't have to worry about writing
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AllTests.c or dealing with any of the other suite code.
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CREDITS
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These people have contributed useful code changes to the CuTest project.
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Thanks!
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- [02.23.2003] Dave Glowacki <dglo@hyde.ssec.wisc.edu>
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- [04.17.2009] Tobias Lippert <herrmarder@googlemail.com>
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- [11.13.2009] Eli Bendersky <eliben@gmail.com>
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- [12.14.2009] Andrew Brown <abrown@datasci.com>
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