SFWR ENG 3S03: Software Testing

Transcription

1 (Slide 1 of 69) Dr. Ridha Khedri Writing in Department of Computing and Software, McMaster University Canada L8S 4L7, Hamilton, Ontario Acknowledgments: Material based on [HT03]

2 Unit Testing in Java with (Slide 2 of 69) 1 2 Excuses For Not Testing Units 3 Assertions as a testing technique Testing a Simple Method How to Run a Test 4 Writing in Structuring Unit Asserts Framework Test Writing in

3 Unit Testing in Java with (Slide 3 of 69) A unit test is a piece of code written by a developer/tester that exercises a very small, specific area of functionality of the code being tested Usually a unit test exercises some particular method in a particular context Add a large value to a sorted list, then confirm that this value appears at the end of the list Excuses For Not Testing Units Writing in Delete a pattern of characters from a string and then confirm that they are gone Unit testing techniques are needed for programmers and testers

4 Unit Testing in Java with (Slide 4 of 69) Fundamentally, you want to answer the question: Is the code fulfilling my intent? By building up confidence that the individual units work as expected, we can then proceed to assemble and test working systems Excuses For Not Testing Units Writing in We still need other forms of testing, and perhaps much more formal testing depending on your environment

5 Unit Testing in Java with (Slide 5 of 69) One nice side-effect of unit testing is that it helps you communicate the code s intended use A unit test behaves as executable documentation, showing how you expect the code to behave under the various conditions you have considered Excuses For Not Testing Units Writing in Team members can look at the tests for examples of how to use your code If someone comes across a test case that you haven t considered, they will be alerted quickly to that fact

6 Unit Testing in Java with (Slide 6 of 69) Unit testing is basically an easy practice to adopt However, there are some guidelines and common steps that you can follow to make it easier and more effective 1 Decide how to test the method in question With at least a rough idea of how to proceed, you proceed to write the test code itself (If you are testing your own code) Excuses For Not Testing Units Writing in 2 You run the test itself, and probably all the other tests in that (part of) the system if that can be done relatively quickly You want to get into the habit of looking at the test results and telling at a glance whether it all worked

7 Unit Testing in Java with (Slide 7 of 69) Excuses For Not Testing Units If I a programmer, It s not my job to test my code I am being paid to write code, not to write tests It takes too long to run the tests Excuses For Not Testing Units Writing in But it compiles! I feel guilty about putting testers and QA staff out of work

8 Unit Testing in Java with (Slide 8 of 69) Excuses For Not Testing Units If I am tester, I don t really know how the code is supposed to behave so I cannot test it It takes too much time to write the tests It takes too long to run the tests Excuses For Not Testing Units Writing in My company won t let me run unit tests on the live system (NOT THE CASE)

9 Unit Testing in Java with (Slide 9 of 69) Recall: a unit test is articulated into a piece of code it is to exercise another piece of code, and determines whether the other piece of code is behaving as expected or not How do you do that, exactly? Using Java Libraries: You can use an assertion, a simple method call that verifies that something is true Assertions as a testing technique Testing a Simple Method How to Run a Test Writing in Write your own assert method

10 Unit Testing in Java with (Slide 10 of 69) Assertions as a testing technique Sometimes, we want to make sure that a program satisfies a certain assumption at a given point The code for an assumption defines an assertion The assert statement allows us to specify an assertion about the program s behaviour The assumption is written as a Boolean expression Assertions as a testing technique Testing a Simple Method How to Run a Test Writing in The Boolean expression is evaluated during program execution If the expression evaluated to false, then an error message is generated the execution is aborted

11 Unit Testing in Java with Assertions as a testing technique Using java -ea FloatingPointArea3 Program Output 1 // Using a s s e r t i o n s to v e r i f y user input and c a l c u l a t e d values. i m p o r t j a v a. u t i l. Scanner ; 3 p u b l i c c l a s s F l o a t i n g P o i n t A r e a 3 { p u b l i c s t a t i c v o i d main ( S t r i n g [ ] a r g s ) { 5 Scanner keyboard = new Scanner ( System. i n ) ; 7 // Read r e c t a n g l e d i m e n s i o n s System. out. p r i n t ( En te r the r e c t a n g l e l e n g t h [ d e c i m a l number ] : ) ; 9 double l e n g t h = keyboard. nextdouble ( ) ; keyboard. n e x t L i n e ( ) ; 11 System. out. p r i n t ( Enter the r e c t a n g l e width [ d e c i m a l number ] : ) ; double width = keyboard. nextdouble ( ) ; 13 // V a l i d a t e u s e r i n p u t 15 a s s e r t l e n g t h > 0. 0 : The l e n g t h o f t h e r e c t a n g l e must be > 0. 0 ; // ( 1 ) a s s e r t width > 0.0 : The width o f t h e r e c t a n g l e must be > 0.0 ; // ( 2 ) 17 double area = l e n g t h width ; // C a l c u l a t e area of the r e c t a n g l e 19 // P r i n t t h e c o r r e c t answer 21 System. out. p r i n t f ( A r e c t a n g l e o f l e n g t h %.2 f cm. and width %.2 f cm. has + 23 a re a %.2 f sq. cm.%n, l e n g t h, width, a r e a ) ; 25 (Slide 11 of 69) Assertions as a testing technique Testing a Simple Method How to Run a Test Writing in Enter the rectangle length [decimal number]: -4 Enter the rectangle width [decimal number]: 1.4 Exception in thread "main" java.lang.assertionerror: The length of the rectangle must be > 0.0 at FloatingPointArea3.main(FloatingPointArea3.java:15)

12 Unit Testing in Java with Assertions as a testing technique Using java FloatingPointArea3 // Using a s s e r t i o n s to v e r i f y user input and c a l c u l a t e d values. 2 i m p o r t j a v a. u t i l. Scanner ; p u b l i c c l a s s F l o a t i n g P o i n t A r e a 3 { 4 p u b l i c s t a t i c v o i d main ( S t r i n g [ ] a r g s ) { Scanner keyboard = new Scanner ( System. i n ) ; 6 // Read r e c t a n g l e d i m e n s i o n s 8 System. out. p r i n t ( Enter the r e c t a n g l e l e n g t h [ d e c i m a l number ] : ) ; double l e n g t h = keyboard. nextdouble ( ) ; 10 keyboard. n e x t L i n e ( ) ; System. out. p r i n t ( En te r the r e c t a n g l e width [ d e c i m a l number ] : ) ; 12 double width = keyboard. nextdouble ( ) ; 14 // V a l i d a t e u s e r i n p u t a s s e r t l e n g t h > 0. 0 : The l e n g t h o f t h e r e c t a n g l e must be > 0. 0 ; // ( 1 ) 16 a s s e r t width > 0.0 : The width o f t h e r e c t a n g l e must be > 0.0 ; // ( 2 ) 18 double area = l e n g t h width ; // C a l c u l a t e area of the r e c t a n g l e 20 // P r i n t t h e c o r r e c t answer System. out. p r i n t f ( 22 A r e c t a n g l e o f l e n g t h %.2 f cm. and width %.2 f cm. has + a r e a %.2 f sq. cm.%n, 24 l e n g t h, width, a r e a ) ; 26 (Slide 12 of 69) Assertions as a testing technique Testing a Simple Method How to Run a Test Writing in Program Output Enter the rectangle length [decimal number]: -4 Enter the rectangle width [decimal number]: 1.4 A rectangle of length cm. and width 1.40 cm. has area sq. cm.

13 Unit Testing in Java with (Slide 13 of 69) Testing a Simple Method Assertions provide a useful testing technique that can help us detect errors early Assertions can be turned on when running the program for test purposes, and turned off when the program is shipped to the user The assertions can be turned on again by means of the -ea flag Assertions as a testing technique Testing a Simple Method How to Run a Test Writing in

14 Unit Testing in Java with (Slide 14 of 69) Testing a Simple Method FEST Assertions 2.0 is a Java library that provides a fluent interface for writing assertions Its main goal is to improve test code readability and make maintenance of tests easier FEST Assertions requires Java SE 6.0 or later and can be used with either or TestNG Assertions as a testing technique Testing a Simple Method How to Run a Test Writing in Currently, it provides assertions for the dat types: Object, String, Collection, Map, Primitives (boolean, int, char, etc.), Arrays of Object, Arrays of primitives, BufferedImage, Throwable, File, BigDecimal

15 Unit Testing in Java with Testing a Simple Method (Slide 15 of 69) You write your own assert function/method You use an assertion method that verifies that something is true Example: Write a method checks that the given boolean condition is true, and s the current test if it is not Assertions as a testing technique Testing a Simple Method How to Run a Test Writing in It might be implemented like the following

16 Unit Testing in Java with Testing a Simple Method (Slide 16 of 69) // 2 // a method a s s e r t T r u e // 4 // // C r e a t e d by Ridha K h e d r i on // // 8 p u b l i c v o i d a s s e r t T r u e ( boolean c o n d i t i o n ) { 10 i f (! c o n d i t i o n ) { a b o r t ( ) ; 12 1 i n t a = 2 ; 3 xx xxx xx x xxx x ; x x x xx xxx xxxx x ; 5 a s s e r t T r u e ( a == 2) ; xxxx xx xx xxx xx ; 7 xxxx xx xx xxx xx ; xxxx xx xx xxx xx ; Assertions as a testing technique Testing a Simple Method How to Run a Test Writing in

17 Unit Testing in Java with (Slide 17 of 69) Testing a Simple Method // 2 // a method a s s e r t T r u e // 4 // // C r e a t e d by Ridha K h e d r i on // // 8 p u b l i c v o i d a s s e r t T r u e ( b o o l e a n c o n d i t i o n ) { 10 i f (! c o n d i t i o n ) { a b o r t ( ) ; // 16 // we could write a method that takes two i n t e g e r parameters // 18 p u b l i c v o i d a s s e r t E q u a l s ( i n t a, i n t b ) { 20 a s s e r t T r u e ( a == b ) ; Assertions as a testing technique Testing a Simple Method How to Run a Test Writing in

18 Unit Testing in Java with (Slide 18 of 69) Testing a Simple Method Example int Largest.largest(int[] list); Given an array of numbers such as [7, 8, 9], this method should return 9 What other tests can you think of? r7, 8, 9s ÝÑ 9 r8, 9, 7s ÝÑ 9 r7, 9, 8, 9s ÝÑ 9 r1s ÝÑ 1 r 9, 8, 7s ÝÑ 7 Assertions as a testing technique Testing a Simple Method How to Run a Test Writing in

19 Unit Testing in Java with Testing a Simple Method 1 p u b l i c c l a s s L a r g e s t { 3 // // Return t h e l a r g e s t e l e m e n t i n a l i s t. 5 // l i s t A l i s t o f i n t e g e r s 7 r e t u r n The l a r g e s t number i n t h e g i v e n l i s t // 9 // // C r e a t e d by Ridha K h e d r i on // // p u b l i c s t a t i c i n t l a r g e s t ( i n t [ ] l i s t ) { i n t index, max=i n t e g e r. MAX VALUE ; 17 f o r ( i n d e x = 0 ; i n d e x < l i s t. l e n g t h 1; i n d e x++) { i f ( l i s t [ i n d e x ] > max ) { max = l i s t [ i n d e x ] ; return max ; 23 (Slide 19 of 69) Assertions as a testing technique Testing a Simple Method How to Run a Test Writing in

20 Unit Testing in Java with Testing a Simple Method (Slide 20 of 69) 2 i m p o r t j u n i t. framework. ; p u b l i c c l a s s T e s t L a r g e s t e x t e n d s TestCase { 4 p u b l i c T e s t L a r g e s t ( S t r i n g name ) { s u p e r ( name ) ; 6 8 p u b l i c v o i d t e s t S i m p l e ( ) { 10 a s s e r t E q u a l s ( 9, L a r g e s t. l a r g e s t ( new i n t [ ] {7,8,9) ) ; 12 Program Output Assertions as a testing technique Testing a Simple Method How to Run a Test Writing in There was 1 ure: 1) testsimple(testlargest)junit.framework.assertionfailederror: expected:<9> but was:< > at TestLargest.testSimple(TestLargest.java:11)

21 Unit Testing in Java with (Slide 21 of 69) Testing a Simple Method 2 p u b l i c c l a s s L a r g e s t { 4 p u b l i c s t a t i c i n t l a r g e s t ( i n t [ ] l i s t ) { i n t index, max = I n t e g e r. MIN VALUE ; 6 f o r ( i n d e x = 0 ; i n d e x < l i s t. l e n g t h 1; i n d e x++) { i f ( l i s t [ i n d e x ] > max ) { max = l i s t [ i n d e x ] ; 8 10 return max ; 12 Assertions as a testing technique Testing a Simple Method How to Run a Test Writing in

22 Unit Testing in Java with Testing a Simple Method (Slide 22 of 69) 1 i m p o r t j u n i t. framework. ; 3 p u b l i c c l a s s T e s t L a r g e s t e x t e n d s TestCase { 5 p u b l i c T e s t L a r g e s t ( S t r i n g name ) { s u p e r ( name ) ; 7 9 p u b l i c v o i d t e s t S i m p l e ( ) { a s s e r t E q u a l s ( 9, L a r g e s t. l a r g e s t ( new i n t [ ] {7,8,9) ) ; p u b l i c v o i d t e s t O r d e r ( ) { a s s e r t E q u a l s ( 9, L a r g e s t. l a r g e s t ( new i n t [ ] {9,8,7) ) ; 15 Assertions as a testing technique Testing a Simple Method How to Run a Test Writing in

23 Unit Testing in Java with (Slide 23 of 69) Testing a Simple Method 2 p u b l i c v o i d t e s t O r d e r ( ) { a s s e r t E q u a l s ( 9, L a r g e s t. l a r g e s t ( new i n t [ ] {9,8,7) ) ; 4 a s s e r t E q u a l s ( 9, L a r g e s t. l a r g e s t ( new i n t [ ] {7,9,8) ) ; 6 8 OR MORE TESTS p u b l i c v o i d t e s t O r d e r ( ) { a s s e r t E q u a l s ( 9, L a r g e s t. l a r g e s t ( new i n t [ ] {9,8,7) ) ; 12 a s s e r t E q u a l s ( 9, L a r g e s t. l a r g e s t ( new i n t [ ] {7,9,8) ) ; a s s e r t E q u a l s ( 9, L a r g e s t. l a r g e s t ( new i n t [ ] {7,8,9) ) ; 14 Program Output Assertions as a testing technique Testing a Simple Method How to Run a Test Writing in There was 1 ure: 1) testorder(testlargest)junit.framework.assertionfailederror: expected:<9> but was:<8> at TestLargest.testOrder(TestLargest.java:10)

24 Unit Testing in Java with Testing a Simple Method 2 p u b l i c c l a s s L a r g e s t { 4 p u b l i c s t a t i c i n t l a r g e s t ( i n t [ ] l i s t ) { i n t index, max = I n t e g e r. MIN VALUE ; 6 f o r ( i n d e x = 0 ; i n d e x < l i s t. l e n g t h 1; i n d e x++) { i f ( l i s t [ i n d e x ] > max ) { max = l i s t [ i n d e x ] ; 8 10 return max ; 12 1 p u b l i c c l a s s L a r g e s t { 3 p u b l i c s t a t i c i n t l a r g e s t ( i n t [ ] l i s t ) { 5 i n t index, max = I n t e g e r. MIN VALUE ; f o r ( i n d e x = 0 ; i n d e x < l i s t. l e n g t h ; i n d e x++) { 7 i f ( l i s t [ i n d e x ] > max ) { max = l i s t [ i n d e x ] ; 9 return max ; (Slide 24 of 69) Assertions as a testing technique Testing a Simple Method How to Run a Test Writing in

25 Unit Testing in Java with 1 Testing a Simple Method 3 import j u n i t. framework. ; 5 p u b l i c c l a s s T e s t L a r g e s t e x t e n d s TestCase { p u b l i c T e s t L a r g e s t ( S t r i n g name ) { 7 s u p e r ( name ) ; 9 11 p u b l i c void t e s t S i m p l e ( ) { a s s e r t E q u a l s (9, L a r g e s t. l a r g e s t (new i n t [ ] {7,8,9) ) ; p u b l i c v o i d testdups ( ) { (9, Largest. largest (new int [ ] {9,7,9,8) ) ; p u b l i c v o i d testone ( ) { a s s e r t E q u a l s (1, L a r g e s t. l a r g e s t (new i n t [ ] {1) ) ; p u b l i c void t e s t N e g a t i v e ( ) { int [ ] neglist = new int [ ] { 9, 8, 7; ( 7, L a r g e s t. l a r g e s t ( n e g L i s t ) ) ; 25 (Slide 25 of 69) Assertions as a testing technique Testing a Simple Method How to Run a Test Writing in 27 p u b l i c v o i d testempty ( ) { t r y { 29 L a r g e s t. l a r g e s t ( new i n t [ ] {) ; f a i l ( Should have thrown an e x c e p t i o n ) ; 31 c a t c h ( R u n t i m e E x c eption e ) { a s s e r t T r u e ( t r u e ) ; 33 35

26 Unit Testing in Java with (Slide 26 of 69) How to Run a Test If is integrated into your IDE, then running a test may be as easy as pressing a button and selecting from a list of available test classes Otherwise, you can always execute a TestRunner manually There are several flavours of test runners To run a GUI version that lets you pick and choose classes (and which remembers them from session to session), run the following class: Assertions as a testing technique Testing a Simple Method How to Run a Test Writing in java junit.swingui.testrunner

27 Unit Testing in Java with (Slide 27 of 69) How to Run a Test You will probably be able to run the junit.swingui.testrunner class from your IDE If not, run it from the command line using the jre or java command (as in previous slide) To run a test using the textual UI, use: java junit.textui.testrunner classname... Assertions as a testing technique Testing a Simple Method How to Run a Test Writing in For instance, to run the unit tests discussed in previous slides: javac Largest.java TestLargest.java java junit.textui.testrunner TestLargest

28 Unit Testing in Java with Writing in (Slide 28 of 69) We have looked at writing tests somewhat informally Now it is time to take a deeper look at the difference between test code and production code We look at all the various forms of s assert, the structure and composition of tests, etc. Writing in Structuring Unit Asserts Framework Test and

29 Unit Testing in Java with Writing in (Slide 29 of 69) Structuring Unit When writing test code, there are some naming conventions you need to follow If you have a method named createaccount that you want to test, then your first test method might be named testcreateaccount The method testcreateaccount will call createaccount with the necessary parameters and verify that createaccount works as specified Writing in Structuring Unit Asserts Framework Test and

30 Unit Testing in Java with Writing in (Slide 30 of 69) Structuring Unit You can have many test methods that exercise createaccount Customers or end-users will never see it or use it The production code must therefore not know anything about the test code Writing in Structuring Unit Asserts Framework Test and

31 Unit Testing in Java with Writing in Structuring Unit TestAccount.java testcreateaccount() testcreateacctdef() testcreateacctdup()... Internal Only Test Code Account.java CreateAccount() Delivered Prod. Code (Slide 31 of 69) Writing in Structuring Unit Asserts Framework Test and

32 Unit Testing in Java with Writing in (Slide 32 of 69) Structuring Unit The test code must be written to do a few things: Setup all conditions needed for testing (create any required objects, allocate any needed resources, etc.) Call the method to be tested Verify that the method to be tested functioned as expected Clean up after itself You write test code and compile it in the normal way (as you would any other bit of source code) It might happen to use some additional libraries, but otherwise it is just regular code Writing in Structuring Unit Asserts Framework Test and

33 Unit Testing in Java with Writing in (Slide 33 of 69) Structuring Unit When it is time to execute the code, remember that you never actually run the production code directly You won t be running it the way a user would You run the test code, which in turn exercises the production code under very carefully controlled conditions Writing in Structuring Unit Asserts Framework Test and

34 Unit Testing in Java with Writing in (Slide 34 of 69) Asserts There are (or we can write) some helper methods that assist us in determining whether a method under test is performing correctly or not We call all these methods asserts They let you assert that some condition is true We will take a look at each one of the assert methods that provides All of the following methods will record ures or errors, and report these through the classes Writing in Structuring Unit Asserts Framework Test and

35 Unit Testing in Java with Writing in (Slide 35 of 69) Asserts For the text version, that means an error message will be printed to the console The GUI version will show a red bar and supporting details to indicate a ure When a ure or error occurs, execution of the current test method is aborted Other tests within the same test class will still be run Asserts are the fundamental building block for unit tests Writing in Structuring Unit Asserts Framework Test and

36 Unit Testing in Java with Writing in (Slide 36 of 69) Asserts ([String message], expected, actual) This is the most-often used form of assert expected is a value you hope to see (typically hard-coded) actual is a value actually produced by the code under test message is an optional message that will be reported in the event of a ure Writing in Structuring Unit Asserts Framework Test and

37 Unit Testing in Java with Writing in (Slide 37 of 69) Asserts Any kind of object may be tested for equality In particular, you can compare the contents of strings using this method Different method signatures are also provided for all the native types (boolean, int, short, etc.) and Object Writing in Structuring Unit Asserts Framework Test and

38 Unit Testing in Java with Writing in (Slide 38 of 69) Asserts Be aware that the equals method for native arrays, does not compare the contents of the arrays (just the array reference itself) If you are using an assert to compare floating point numbers (floats or doubles in Java), you need to specify one additional piece of information, the tolerance This specifies just how close to?equals? you need the result to be For most business applications, 4 or 5 decimal places is probably enough For scientific apps, you may need much greater precision Writing in Structuring Unit Asserts Framework Test and

39 Unit Testing in Java with Writing in (Slide 39 of 69) Asserts Example ([String message], expected, actual, tolerance) ( Should be 3 1/3, 3.33, 10.0/3.0, 0.01); Writing in Structuring Unit Asserts Framework Test and

40 Unit Testing in Java with Writing in (Slide 40 of 69) Asserts ([String message], java.lang.object object) assertnotnull assertnotnull([string message], java.lang.object object) Asserts that the given object is null (or not null), ing otherwise Writing in Structuring Unit Asserts Framework Test and

41 Unit Testing in Java with Writing in (Slide 41 of 69) Asserts ([String message], expected, actual) assertnotsame assertnotsame([string message], expected, actual) The first asserts that expected and actual refer to the same object, and s the test if they do not The second asserts that expected and actual do not refer to the same object, and s the test if they are the same object Writing in Structuring Unit Asserts Framework Test and

42 Unit Testing in Java with Writing in (Slide 42 of 69) Asserts ([String message], boolean condition) Asserts that the given boolean condition is true, otherwise the test s assertfalse assertfalse([string message], boolean condition) Writing in Structuring Unit Asserts Framework Test and

43 Unit Testing in Java with Writing in (Slide 43 of 69) Asserts ([String message]) Fails the test immediately, with the optional message Often used to mark sections of code that should not be reached (for instance, after an exception is expected) Writing in Structuring Unit Asserts Framework Test and

44 Unit Testing in Java with Writing in Asserts You usually have multiple asserts in a given test method When an assert s, that test method will be aborted the remaining assertions in that method will not be executed this time You have to fix the ing test before you can proceed (Programmer) And you fix the next ing test. And the next. And so on. (Programmer) Programmer: Under no circumstances should you continue to add features when there are ing tests! (Slide 44 of 69) Writing in Structuring Unit Asserts Framework Test and

45 Unit Testing in Java with Writing in (Slide 45 of 69) Framework So far, we have just looked at the assert methods We need a little bit more of a structure around the asserts (a framework) Follows is a very simple piece of test code that illustrates the minimum framework we need to get started Writing in Structuring Unit Asserts Framework Test and

46 Unit Testing in Java with Writing in Framework (Slide 46 of 69) i m p o r t j u n i t. framework. ; 2 p u b l i c c l a s s T e s t S i m p l e e x t e n d s TestCase { 4 p u b l i c T e s t S i m p l e ( S t r i n g name ) { s u p e r ( name ) ; 6 8 p u b l i c v o i d t e s t A d d ( ) { a s s e r t E q u a l s ( 2, 1+1) ; 10 The import statement on line 1 brings in the necessary classes On line 3, we have the class defynition (each class that contains tests must extend TestCase as shown) The base class TestCase provides most of the unit-testing functionality that we need (including all of the assert methods) Writing in Structuring Unit Asserts Framework Test and

47 Unit Testing in Java with Writing in (Slide 47 of 69) Framework The base class requires a constructor that takes a String 1 i m p o r t j u n i t. framework. ; 3 p u b l i c c l a s s T e s t S i m p l e e x t e n d s TestCase { p u b l i c T e s t S i m p l e ( S t r i n g name ) { 5 s u p e r ( name ) ; 7 p u b l i c v o i d t e s t A d d ( ) { 9 a s s e r t E q u a l s ( 2, 1+1) ; 11 Finally, the test class contains a method named testadd on line 9 (It is the one we wanted to use in the example) All methods with names that begin with test will be run automatically by We can also specify particular methods to run by defining a suite method (To be discussed) Writing in Structuring Unit Asserts Framework Test and

48 Unit Testing in Java with Writing in (Slide 48 of 69) Framework 1 i m p o r t j u n i t. framework. ; 3 p u b l i c c l a s s T e s t S i m p l e e x t e n d s TestCase { p u b l i c T e s t S i m p l e ( S t r i n g name ) { 5 s u p e r ( name ) ; 7 p u b l i c v o i d t e s t A d d s ( ) { 9 a s s e r t E q u a l s ( 2, 1+1) ; a s s e r t E q u a l s ( 4, 2+2) ; 11 a s s e r t E q u a l s ( 8, 12+4) ; 13 In the previous example, we showed ONE test, using ONE assert, in ONE test method Inside a test method, we can place any number of asserts Writing in Structuring Unit Asserts Framework Test and

49 Unit Testing in Java with Writing in (Slide 49 of 69) Test Summary: A test class contains test methods Each method contains one or more assert statements A test class can also invoke other test classes: individual classes, packages, or even the whole system We can better structure our testing by creating test suites Writing in Structuring Unit Asserts Framework Test and

50 Unit Testing in Java with Writing in (Slide 50 of 69) Test Any test class can contain a static method named suite public static Test suite(); We can provide a suite() method to return any collection of tests we want Without a suite() method, runs all of the test... methods automatically We might also want to add particular tests by hand Writing in Structuring Unit Asserts Framework Test and

51 Unit Testing in Java with Writing in Test 1 import j u n i t. framework. ; 3 p u b l i c c l a s s TestClassTwo e x t e n d s TestCase { public TestClassTwo ( String method ) { 5 s u p e r ( method ) ; 7 // This one t a k e s a few h o u r s... 9 p u b l i c v o i d testlongrunner ( ) { 11 TSP t s p = new TSP ( ) ; // Load w i t h d e f a u l t c i t i e s (2300, tsp. shortestpath (50) ) ; // top p u b l i c void t e s t S h o r t T e s t ( ) { TSP t s p = new TSP ( ) ; // Load w i t h d e f a u l t c i t i e s 17 a s s e r t E q u a l s ( 14 0, t s p. s h o r t e s t P a t h ( 5 ) ) ; // top 5 19 p u b l i c void t e st A no th e rs h or tt e st ( ) { 21 TSP t s p = new TSP ( ) ; // Load w i t h d e f a u l t c i t i e s a s s e r t E q u a l s (5 86, t s p. s h o r t e s t P a t h (1 0 ) ) ; // top p u b l i c s t a t i c Test s u i t e ( ) { T e s t S u i t e s u i t e = new T e s t S u i t e ( ) ; 27 // Only i n c l u d e s h o r t tests suite. addtest ( 29 new TestClassTwo ( testshorttest ) ) ; 31 suite. addtest ( new TestClassTwo ( testanothershorttest ) 33 ) ; return s u i t e ; 35 (Slide 51 of 69) Writing in Structuring Unit Asserts Framework Test and

52 Unit Testing in Java with Writing in (Slide 52 of 69) Test Basic test Skeleton: Provides a mechanism to run test // package... 2 import j u n i t. framework. ; // Change a l l occurrences 4 // as a p p r o p r i a t e 6 p u b l i c c l a s s T e s t S k e l e t o n o f S k e l e t o n below e x t e n d s TestCase { / 8 Per method t e s t s e t up / 10 p u b l i c v o i d setup ( ) { 12 / 14 Per method t e s t t e a r down / 16 p u b l i c v o i d teardown ( ) { 18 / 20 Add t e s t s here : p u b l i c v o i d testname ( ) / p u b l i c T e s t S k e l e t o n ( S t r i n g name ) { 24 s u p e r ( name ) ; 26 / 28 D e f a u l t s u i t e method / 30 p u b l i c s t a t i c Test s u i t e ( ) { r e t u r n new T e s t S u i t e ( T e s t S k e l e t o n. c l a s s ) ; 32 // THE REST OF THE SKELETON i s on NEXT SLIDE Writing in Structuring Unit Asserts Framework Test and

53 Unit Testing in Java with Writing in (Slide 53 of 69) Test Basic test Skeleton... CONTINUED... 1 // Test S k e l e t o n CONTINUED from p r e v i o u s s l i d e 3 / Note main w i l l only be run when invoked i n d i v i d u a l l y from t h e command l i n e 5 ( not v i a A n t s J U n i t Task, e t c. ) / 7 p u b l i c s t a t i c v o i d main ( S t r i n g [ ] a r g s ) { T e s t S u i t e s u i t e = new T e s t S u i t e ( ) ; 9 i f ( a r g s. l e n g t h!= 0) { // Run s p e c i f i c t e s t s as i n d i c a t e d from t h e 11 // command l i n e f o r ( i n t i =0; i< a r g s. l e n g t h ; i ++) { 13 s u i t e. addtest ( new T e s t S k e l e t o n ( a r g s [ i ] ) ) ; 15 e l s e { // Dynamically discover a l l of them, or use 17 // u s e r d e f i n e d s u i t e suite. addtest ( TestSkeleton. suite ( ) ) ; 19 j u n i t. t e x t u i. TestRunner. run ( s u i t e ) ; 21 Writing in Structuring Unit Asserts Framework Test and

54 Unit Testing in Java with Writing in (Slide 54 of 69) Test The String parameter to the constructor lets a TestCase return a reference to a named test method We can use it to get references to the two short-running tests to populate our test suite You might want to have a higher-level test that is composed of test classes Writing in Structuring Unit Asserts Framework Test and

55 Unit Testing in Java with Writing in Test i m p o r t j u n i t. framework. ; 2 public c l a s s TestClassComposite extends TestCase { 4 public TestClassComposite ( String method ) { 6 s u p e r ( method ) ; 8 s t a t i c p u b l i c Test s u i t e ( ) { 10 T e s t S u i t e s u i t e = new T e s t S u i t e ( ) ; // Grab everything : 12 s u i t e. a d d T e s t S u i t e ( TestClassOne. c l a s s ) ; // Use t h e s u i t e method : 14 s u i t e. addtest ( TestClassTwo. s u i t e ( ) ) ; r e t u r n s u i t e ; 16 If you run TestClassComposite, we run the test methods: testaddition() from TestClassOne testsubtraction() from TestClassOne testshorttest() from TestClassTwo testanothershorttest() from TestClassTwo We can keep going with this scheme, by writing another class include TestClassComposite (Slide 55 of 69) Writing in Structuring Unit Asserts Framework Test and

56 Unit Testing in Java with Writing in (Slide 56 of 69) Test Each test should run independently of every other test This allows you to run any individual test at any time, in any order For this purpose, we may need to reset some parts of the testing environment in between tests, or clean up after a test has run s TestCase base class provides two methods that you can override to set up and then tear down the test s environment protected void setup(); (Called before each testxxxx ) protected void teardown(); (Called after each testxxxx ) Writing in Structuring Unit Asserts Framework Test and

57 Unit Testing in Java with Writing in (Slide 57 of 69) Test Example of Execution Order of Setup Code Writing in Structuring Unit Asserts Framework Test and

58 Unit Testing in Java with Writing in (Slide 58 of 69) Test Example: Overriding of setup and teardown 1 p u b l i c c l a s s TestDB e x t e n d s TestCase { p r i v a t e C o n n e c t i o n dbconn ; 3 p r o t e c t e d v o i d setup ( ) { 5 dbconn = new C o n n e c t i o n ( o r a c l e, 1521, Fred, f o o b a r ) ; dbconn. c o n n e c t ( ) ; 7 9 p r o t e c t e d v o i d teardown ( ) { dbconn. d i s c o n n e c t ( ) ; dbconn = n u l l ; p u b l i c v o i d t e s t A c c o u n t A c c e s s ( ) { // Uses dbconn 15 xxx xxx xxxxxx xxx xxxxxxxxx ; xx xxx xxx xxxx x xx xxxx ; p u b l i c v o i d t e s t E m p l o y e e A c c e s s ( ) { // Uses dbconn 21 xxx xxx xxxxxx xxx xxxxxxxxx ; xxxx x x xx xxx xx xxxx ; 23 Writing in Structuring Unit Asserts Framework Test and

59 Unit Testing in Java with Writing in (Slide 59 of 69) Test Normally per-test setup is all we need But in some circumstances, we may need to set something up or clean up after the entire test suite has run In this case, we need per-suite setup and tear-down Per-suite setup is a bit more complicated Provide a suite of the required tests Wrap it in a TestSetup object Writing in Structuring Unit Asserts Framework Test and

60 Unit Testing in Java with Writing in (Slide 60 of 69) Test Example: i m p o r t j u n i t. framework. ; i m p o r t j u n i t. e x t e n s i o n s. ; 2 p u b l i c c l a s s TestClassTwo e x t e n d s TestCase { p r i v a t e s t a t i c TSP t s p ; 4 p u b l i c TestClassTwo ( S t r i n g method ) { 6 s u p e r ( method ) ; 8 // This one t a k e s a few h o u r s p u b l i c v o i d t e s t L o n g R u n n e r ( ) { a s s e r t E q u a l s (2300, t s p. s h o r t e s t P a t h ( 5 0 ) ) ; p u b l i c v o i d t e s t S h o r t T e s t ( ) { a s s e r t E q u a l s ( 1 4 0, t s p. s h o r t e s t P a t h ( 5 ) ) ; p u b l i c v o i d t e s t A n o t h e r S h o r t T e s t ( ) { a s s e r t E q u a l s ( 5 8 6, t s p. s h o r t e s t P a t h ( 1 0 ) ) ; 20 // CONTINUED ON NEXT SLIDE Writing in Structuring Unit Asserts Framework Test and

61 Unit Testing in Java with Writing in Test // Continued from PREVIOUS SLIDE 2 p u b l i c s t a t i c Test s u i t e ( ) { 4 T e s t S u i t e s u i t e = new T e s t S u i t e ( ) ; // Only i n c l u d e s h o r t t e s t s 6 s u i t e. addtest ( new TestClassTwo ( t e s t S h o r t T e s t ) ) ; s u i t e. addtest ( new TestClassTwo ( t e s t A n o t h e r S h o r t T e s t ) ) ; 8 TestSetup wrapper = new TestSetup ( s u i t e ) { 10 p r o t e c t e d v o i d setup ( ) { onetimesetup ( ) ; p r o t e c t e d v o i d teardown ( ) { onetimeteardown ( ) ; 16 ; 18 r e t u r n wrapper ; 20 p u b l i c s t a t i c v o i d onetimesetup ( ) { 22 // one time i n i t i a l i z a t i o n code goes h e r e... t s p = new TSP ( ) ; 24 t s p. l o a d C i t i e s ( E a s t e r n S e a b o a r d ) ; 26 p u b l i c s t a t i c v o i d onetimeteardown ( ) { 28 // one time c l e a n u p code goes h e r e... t s p. r e l e a s e C i t i e s ( ) ; 30 (Slide 61 of 69) Writing in Structuring Unit Asserts Framework Test and

62 Unit Testing in Java with Writing in (Slide 62 of 69) Test and There are two kinds of exceptions that we might be interested in: Expected exceptions resulting from a test Unexpected exceptions from something that is gone wrong In a test, we want the method under test to throw an exception Writing in Structuring Unit Asserts Framework Test and

63 Unit Testing in Java with Writing in (Slide 63 of 69) Test and Consider a method named sortmylist() that is supposed to throw an exception if passed a null list 1 p u b l i c v o i d t e s t F o r E x c e p t i o n ( ) { t r y { 3 s o r t M y L i s t ( n u l l ) ; f a i l ( Should have thrown an e x c e p t i o n ) ; 5 catch ( RuntimeException e ) { a s s e r t T r u e ( t r u e ) ; 7 Writing in Structuring Unit Asserts Framework Test and

64 Unit Testing in Java with Writing in (Slide 64 of 69) For sets of tests with large amounts of test data Consider putting the test values and/or results in a separate data file that the unit test reads in It is a very complicated exercise The next example illustrate this usage of data files Writing in Structuring Unit Asserts Framework Test and

65 Unit Testing in Java with Writing in (Slide 65 of 69) The data file has a very simple format For example, each line contains a set of numbers The first number is the expected answer The numbers on the rest of the line are the arguments with which to test We allow a pound-sign (#) for comments, so that you can put notes in the test file Writing in Structuring Unit Asserts Framework Test and

66 Unit Testing in Java with Writing in (Slide 66 of 69) # # Simple tests: # # # Negative number tests: # # # Mixture: # # # Boundary conditions: # Writing in Structuring Unit Asserts Framework Test and

67 Unit Testing in Java with Writing in i m p o r t j u n i t. framework. ; 2 i m p o r t j a v a. i o. ; i m p o r t j a v a. u t i l. A r r a y L i s t ; 4 i m p o r t j a v a. u t i l. S t r i n g T o k e n i z e r ; 6 public c l a s s TestLargestDataFile extends TestCase { p u b l i c T e s t L a r g e s t D a t a F i l e ( S t r i n g name ) { 8 s u p e r ( name ) ; 10 / Run a l l t h e t e s t s i n t e s t d a t a. t x t ( does not t e s t 12 e x c e p t i o n c a s e ). We w i l l g e t an e r r o r i f any o f t h e f i l e I /O goes wrong. 14 / 16 p u b l i c void t e s t F r o m F i l e ( ) throws Exception { S t r i n g l i n e ; 18 B u f f e r e d R e a d e r r d r = new B u f f e r e d R e a d e r ( new F i l e R e a d e r ( t e s t d a t a. t x t ) ) ; 20 w h i l e ( ( l i n e = r d r. r e a d L i n e ( ) )!= n u l l ) { i f ( l i n e. s t a r t s W i t h ( # ) ) { // I g n o r e comments 22 continue ; 24 StringTokenizer st = new StringTokenizer ( l i n e ) ; 26 i f (! s t. hasmoretokens ( ) ) { c o n t i n u e ; // Blank l i n e //.... CONTINUED ON NEXT SLIDE (Slide 67 of 69) Writing in Structuring Unit Asserts Framework Test and

68 Unit Testing in Java with Writing in (Slide 68 of 69) 2 // CONTINUED FROM PREVIOUS SLIDE 4 // Get t h e e x p e c t e d v a l u e S t r i n g v a l = s t. nexttoken ( ) ; 6 i n t e x p e c t e d = I n t e g e r. v a l u e O f ( v a l ). i n t V a l u e ( ) ; // And t h e arguments to L a r g e s t 8 A r r a y L i s t a r g u m e n t l i s t = new A r r a y L i s t ( ) ; 10 w h i l e ( s t. hasmoretokens ( ) ) { a r g u m e n t l i s t. add ( I n t e g e r. v a l u e O f ( s t. nexttoken ( ) ) ) ; 12 // T r a n s f e r o b j e c t l i s t i n t o n a t i v e a r r a y 14 i n t [ ] arguments = new i n t [ a r g u m e n t l i s t. s i z e ( ) ] ; 16 f o r ( i n t i =0; i < a r g u m e n t l i s t. s i z e ( ) ; i ++) { arguments [ i ] = ( ( I n t e g e r ) a r g u m e n t l i s t. g e t ( i ) ). i n t V a l u e ( ) ; // And run t h e a s s e r t a s s e r t E q u a l s ( expected, L a r g e s t. l a r g e s t ( arguments ) ) ; Writing in Structuring Unit Asserts Framework Test and

69 References I (Slide 69 of 69) Andy Hunt and Dave Thomas, Pragmatic unit testing in java with junit, The Pragmatic Programmers, LLC, Writing in Structuring Unit Asserts Framework Test and