【笔记】Eclipse and Java for Total Beginners—006

Lesson 06 – Using Test-First Development in Eclipse

• Use test-first approach to write the Person toString() method
• Method overriding
• Field Hiding

1. toString() method

• inherited from Object class
• returns a String representation of the object
• normally create for every class

2. Test-driven development

• Think about what the method should do.
• Write a test case that will test this method.
• Write the new method.
• Test the new method.
• when it passes.. we’re done!

3. Test-driven development benefits

• Forced to create detailed specifications before coding.
• Test method serves as specification, documentation, and as unit test.
• When method passes the test, method is complete and correct.

  
    

   
      1 
   
     package
   
      org.totalbeginner.tutorial;

   
      2 
   
     

   
      3 
   
      
   
     import
   
      org.totoalbeginner.tutorial.Person;

   
      4 
   
     

   
      5 
   
      
   
     import
   
      junit.framework.TestCase;

   
      6 
   
     

   
      7 
   
      
   
     public
   
      
   
     class
   
      PersonTest 
   
     extends
   
      TestCase {

   
      8 
   
     

   
      9 
   
      
   
     public
   
      
   
     void
   
      testPerson() {

   
     10 
   
      Person p1 
   
     =
   
      
   
     new
   
      Person();

   
     11 
   
      assertEquals(
   
     "
   
     unknown name
   
     "
   
     , p1.getName());

   
     12 
   
      assertEquals(
   
     3
   
     , p1.getMaximumBooks());

   
     13 
   
      }

   
     14 
   
     

   
     15 
   
      
   
     public
   
      
   
     void
   
      testSetName() {

   
     16 
   
      Person p2 
   
     =
   
      
   
     new
   
      Person();

   
     17 
   
      p2.setName(
   
     "
   
     Fred
   
     "
   
     );

   
     18 
   
      assertEquals(
   
     "
   
     Fred
   
     "
   
     , p2.getName());

   
     19 
   
      }

   
     20 
   
     

   
     21 
   
      
   
     public
   
      
   
     void
   
      testSetMaximumBooks() {

   
     22 
   
      Person p3 
   
     =
   
      
   
     new
   
      Person();

   
     23 
   
      p3.setMaximumBooks(
   
     10
   
     );

   
     24 
   
      assertEquals(
   
     10
   
     , p3.getMaximumBooks());

   
     25 
   
      }

   
     26 
   
      

   
     27 
   
      
   
     public
   
      
   
     void
   
      testToString() {

   
     28 
   
      Person p4 
   
     =
   
      
   
     new
   
      Person();

   
     29 
   
      p4.setName(
   
     "
   
     Fred Flintstone
   
     "
   
     );

   
     30 
   
      p4.setMaximumBooks(
   
     7
   
     );

   
     31 
   
      String testString 
   
     =
   
      
   
     "
   
     Fred Flintstone (7 books)
   
     "
   
     ;

   
     32 
   
      assertEquals(testString, p4.toString());

   
     33 
   
      }

   
     34 
   
     

   
     35 
   
     }
  
    

  
    

   
      1 
   
     package
   
      org.totoalbeginner.tutorial;

   
      2 
   
     

   
      3 
   
      
   
     public
   
      
   
     class
   
      Person {

   
      4 
   
      

   
      5 
   
      
   
     //
   
      fields
   
     

   
      6 
   
     
   
      
   
     private
   
      String name; 
   
     //
   
      name of the person
   
     

   
      7 
   
     
   
      
   
     private
   
      
   
     int
   
      maximumBooks; 
   
     //
   
      most books the person can check out

   
      8 
   
      

   
      9 
   
      
   
     //
   
      constructors
   
     

   
     10 
   
     
   
      
   
     public
   
      Person() {

   
     11 
   
      name 
   
     =
   
      
   
     "
   
     unknown name
   
     "
   
     ;

   
     12 
   
      maximumBooks 
   
     =
   
      
   
     3
   
     ;

   
     13 
   
      }

   
     14 
   
      

   
     15 
   
      
   
     //
   
      methods
   
     

   
     16 
   
     
   
      
   
     public
   
      String getName() {

   
     17 
   
      
   
     return
   
      name;

   
     18 
   
      }

   
     19 
   
      

   
     20 
   
      
   
     public
   
      
   
     void
   
      setName(String anyName) {

   
     21 
   
      name 
   
     =
   
      anyName; 

   
     22 
   
      }

   
     23 
   
     

   
     24 
   
      
   
     public
   
      
   
     int
   
      getMaximumBooks() {

   
     25 
   
      
   
     return
   
      maximumBooks;

   
     26 
   
      }

   
     27 
   
     

   
     28 
   
      
   
     public
   
      
   
     void
   
      setMaximumBooks(
   
     int
   
      maximumBooks) {

   
     29 
   
      
   
     this
   
     .maximumBooks 
   
     =
   
      maximumBooks;

   
     30 
   
      }

   
     31 
   
      

   
     32 
   
      
   
     public
   
      String toString() {

   
     33 
   
      
   
     return
   
      
   
     this
   
     .getName() 
   
     +
   
      
   
     "
   
      (
   
     "
   
      
   
     +
   
      getMaximumBooks()

   
     34 
   
      
   
     +
   
      
   
     "
   
      books)
   
     "
   
     ;

   
     35 
   
      }

   
     36 
   
     

   
     37 
   
     }