[SOLVED] Comp1210 project: ringtorus with junit tests – part 3

Overview: This project consists of four classes: (1) RingTorus is a class representing a RingTorus
object; (2) RingTorusTest class is a JUnit test class which contains one or more test methods for each
method in the RingTorus class; (3) RingTorusList is a class representing a RingTorus list object; and
(4) RingTorusListTest class is a JUnit test class which contains one or more test methods for each
method in the RingTorusList class. Note that there is no requirement for a class with a main method
in this project.
You should create a new folder to hold the files for this project and add your files from Part 2
(RingTorus.java file and RingTorusTest.java). You should create a new jGRASP project for Part 3
and add RingTorus.java file and RingTorusTest.java to the project; you should see the two files in
their respective categories – Source Files and Test Files. If RingTorusTest.java appears in source File
category, you should right-click on the file and select “Mark As Test” from the right-click menu.
Project: RingTorus with JUnit Tests – Part 3 Page 2 of 9
Page 2 of 9
You will then be able to run the test file by clicking the JUnit run button on the Open Projects toolbar.
After RingTorusList.java and RingTorusListTest.java are created as specified below, these should be
added to your jGRASP project for Part 3 as well.
If you have successfully completed RingTorus.java and RingTorusTest.java in Part 2, you
should go directly to RingTorusList.java on page 6.
• RingTorus.java (new items for this class in Part 2 are underlined)
Requirements: Create a RingTorus class that stores the label, small radius, and large radius
where the small radius is less than the large radius and both are positive. The RingTorus class
also includes methods to set and get each of these fields, as well as methods to calculate the
outside diameter, surface area, and volume of a RingTorus object, and a method to provide a
String value that describes a RingTorus object. The RingTorus class includes a one static field
(or class variable) to track the number of RingTorus objects that have been created, as well
appropriate static methods to access and reset this field. And finally, this class provides a method
that JUnit will use to test RingTorus objects for equality as well as a method required by
Checkstyle. In addition, RingTorus must implement the Comparable interface for objects of type
RingTorus.
Design: The RingTorus class implements the Comparable interface for objects of type
RingTorus and has fields, a constructor, and methods as outlined below (last method is new).
(1) Fields: Instance Variables – label of type String, large radius of type double, and small
radius of type double. Initialize the String to “” and the double variables to 0 in their
respective declarations. These instance variables should be private so that they are not
directly accessible from outside of the RingTorus class, and these should be the only instance
variables (fields) in the class.
Class Variable – count of type int should be private and static, and it should be initialized to
zero in the declaration.
(2) Constructor: Your RingTorus class must contain a public constructor that accepts three
parameters (see types of above) representing the label, large radius, and small radius. Instead
of assigning the parameters directly to the fields, the respective set method for each field
(described below) should be called since they are checking the validity of the parameter. For
example, instead of using the statement label = labelIn; use the statement
setLabel(labelIn);
After setLabel is called be sure to call setLargeRadius before calling setSmallRadius. The
constructor should increment the class variable count each time a RingTorus is constructed.
Below are examples of how the constructor could be used to create RingTorus objects. Note
that although String and numeric literals are used for the actual parameters (or arguments) in
these examples, variables of the required type could have been used instead of the literals.
Project: RingTorus with JUnit Tests – Part 3 Page 3 of 9
Page 3 of 9
RingTorus ex1 = new RingTorus (“Small Example”, 9.5, 1.25);
RingTorus ex2 = new RingTorus (” Medium Example “, 35.1, 10.4);
RingTorus ex3 = new RingTorus (“Large Example”, 134.28, 32.46);
(3) Methods: Usually a class provides methods to access and modify each of its instance
variables (known as get and set methods) along with any other required methods. The
methods for RingTorus, which should each be public, are described below. See the formulas
in the figure above and the Code and Test section below for information on constructing these
methods.
o getLabel: Accepts no parameters and returns a String representing the label field.
o setLabel: Takes a String parameter and returns a boolean. If the String
parameter is not null, then the “trimmed” String is set to the label field and the
method returns true. Otherwise, the method returns false and the label is not set.
o getLargeRadius: Accepts no parameters and returns a double representing the
large radius field.
o setLargeRadius: Takes a double parameter and returns a boolean. If the
double parameter is positive and is greater than the current small radius, then the
parameter is assigned to the large radius field and the method returns true. Otherwise,
the method returns false and the large radius field is not set.
o getSmallRadius: Accepts no parameters and returns a double representing the
small radius field.
o setSmallRadius: Takes a double parameter and returns a boolean. If the
double parameter is positive and is less than the current large radius, then the parameter
is assigned to the small radius field and the method returns true. Otherwise, the method
returns false and the small radius field is not set.
o diameter: Accepts no parameters and returns a double representing the diameter of
the RingTorus. See formula in figure on page 1.
o surfaceArea: Accepts no parameters and returns the double value for the surface
area of the RingTorus. See formula in figure on page 1.
o volume: Accepts no parameters and returns the double value for the volume of the
RingTorus. See formula in figure on page 1.
o toString: Returns a String containing the information about the RingTorus object
formatted as shown below, including decimal formatting (“#,##0.0##”) for the double
values. Newline and tab escape sequences should be used to achieve the proper layout
within the String but it should not begin or end with a newline. In addition to the field
values (or corresponding “get” methods), the following methods should be used to
compute appropriate values in the toString method: diameter(),
surfaceArea(), and volume(). Each line should have no trailing spaces (e.g., there
should be no spaces before a newline (
) character). The toString value for ex1,
ex2, and ex3 respectively are shown below (the blank lines are not part of the
toString values).
Project: RingTorus with JUnit Tests – Part 3 Page 4 of 9
Page 4 of 9
RingTorus “Small Example”
large radius = 9.5 units
small radius = 1.25 units
diameter = 21.5 units
surface area = 468.806 square units
volume = 293.004 cubic units
RingTorus “Medium Example”
large radius = 35.1 units
small radius = 10.4 units
diameter = 91.0 units
surface area = 14,411.202 square units
volume = 74,938.248 cubic units
RingTorus “Large Example”
large radius = 134.28 units
small radius = 32.46 units
diameter = 333.48 units
surface area = 172,075.716 square units
volume = 2,792,788.867 cubic units
o getCount: A static method that accepts no parameters and returns an int representing
the static count field.
o resetCount: A static method that returns nothing, accepts no parameters, and sets the
static count field to zero.
o equals: An instance method that accepts a parameter of type Object and returns false if
the Object is a not a RingTorus; otherwise, when cast to a RingTorus, if it has the same
field values (ignoring case in the label field) as the RingTorus upon which the method
was called, it returns true. Otherwise, it returns false. Note that this equals method with
parameter type Object will be called by the JUnit Assert.assertEquals method when two
RingTorus objects are checked for equality.
Below is a version you are free to use.
public boolean equals(Object obj) {

if (!(obj instanceof RingTorus )) {
return false;
}
else {
RingTorus rt = (RingTorus ) obj;
return (label.equalsIgnoreCase(rt.getLabel())
&& (Math.abs(largeRadius – rt.getLargeRadius()) < .000001)
&& (Math.abs(smallRadius – rt.getSmallRadius()) < .000001));
}
}
o hashCode(): Accepts no parameters and returns zero of type int. This method is
required by Checkstyle if the equals method above is implemented.
o compareTo: Accepts a parameter of type RingTorus and returns an int as follows: a
negative value if this.volume() is less than the parameter’s volume; a positive value
Project: RingTorus with JUnit Tests – Part 3 Page 5 of 9
Page 5 of 9
if this.volume() is greater than the parameter’s volume; zero if the two volumes are
essentially equal. For a hint, see the activity for this module.
Code and Test: As you implement the methods in your RingTorus class, you should compile it
and then create test methods as described below for the RingTorusTest class.
When using the setSmallRadius and setLargeRadius, the values of the current smallRadius and
largeRadius must be considered to decide the order in which you invoke the associated set
methods. For setSmallRadius, the “new” small radius must be positive and smaller the current
large radius, and for setLargeRadius, the “new” large radius must be positive and larger the
current small radius. For example, a new RingTorus object has its smallRadius and largeRadius
fields initialized to zero in the field declaration, which is default initial value for doubles.
However, this means in the constructor, you must invoke the setLargeRadius before the
setSmallRadius. If you wanted a small radius of 2.5 and attempt to set it first, it would not be set
since it will not be less than largeRadius, which is initially zero. Thus, you invoke setLargeRadius
first since any positive value will be greater than the smallRadius which is initially zero.
Therefore, in general you need to consider the current value the smallRadius and largeRadius to
decide the order you invoke the associated set methods.
• RingTorusTest.java
Requirements: Create a RingTorusTest class that contains a set of test methods to test each of
the methods in RingTorus. The goal for Part 2 is method, statement, and condition coverage.
Design: Typically, in each test method, you will need to create an instance of RingTorus, call the
method you are testing, and then make an assertion about the expected result and the actual result
(note that the actual result is commonly the result of invoking the method unless it has a void
return type). You can think of a test method as simply formalizing or codifying what you could
be doing in jGRASP interactions to make sure a method is working correctly. That is, the
sequence of statements that you would enter in interactions to test a method should be entered
into a single test method. You should have sufficient test methods so that each method,
statement, and condition in RingTorus are covered. Collectively, these test methods are a set of
test cases that can be invoked with a single click to test all the methods in your RingTorus class.
Code and Test: A good strategy would be to begin by writing test methods for those methods in
RingTorus that you “know” are correct. By doing this, you will be able to concentrate on the
getting the test methods correct. That is, if the test method fails, it is most likely due to a defect
in the test method itself rather the RingTorus method being testing. As you become more
familiar with the process of writing test methods, you will be better prepared to write the test
methods as new methods are developed. Be sure to call the RingTorus toString method in
one of your test methods and assert something about the return value. If you do not want to use
assertEquals, which would require the return value match the expected value exactly, you could
use assertTrue and check that the return value contains the expected value. For example, for
RingTorus example3:
Assert.assertTrue(example3.toString().contains(“”Large Example””));
Project: RingTorus with JUnit Tests – Part 3 Page 6 of 9
Page 6 of 9
Also, remember that you can set a breakpoint in a JUnit test method and run the test file in Debug
mode. Then, when you have an instance in the Debug tab, you can unfold it to see its values or
you can open a canvas window and drag items from the Debug tab onto the canvas. You can also
step-in to the method being called by the test method and then single-step through it, looking for
the error.
• RingTorusList.java (new for Part 3) – Consider implementing this file in parallel with its test
file, RingTorusListTest.java, which is described after this class.
Requirements: Create a RingTorusList class that stores the name of the list and an array of
RingTorus objects. It also includes methods that return the name of the list, number of RingTorus
objects in the RingTorusList, total surface area, total volume, average surface area, and average
volume for all RingTorus objects in the RingTorusList. The toString method returns summary
information about the list (see below).
Design: The RingTorusList class has three fields, a constructor, and methods as outlined below.
(1) Fields (or instance variables): (1) a String representing the name of the list, (2) an array of
RingTorus objects, and (3) an int representing the number of RingTorus objects in the
array, which may be less than the length of the array of RingTorus objects. These instance
variables should be private so that they are not directly accessible from outside of the
RingTorusList class. These should be the only fields (or instance variables) in this class, and
they should be initialized in the constructor described below.
(2) Constructor: Your RingTorusList class must contain a constructor that accepts three
parameters: (1) a parameter of type String representing the name of the list, (2) a parameter of
type RingTorus[], representing the list of RingTorus objects, and (3) a parameter of type
int representing the number of RingTorus objects in the array. These parameters should be
used to assign the fields described above (i.e., the instance variables).
(3) Methods: The methods for RingTorusList are described below.
o getName: Returns a String representing the name of the list.
o numberOfRingToruses: Returns an int (the value of the third field in the
RingTorusList object) representing the number of RingTorus objects in the
RingTorusList.
o totalDiameter: Returns a double representing the total diameters for all RingTorus
objects in the list. If there are zero RingTorus objects in the list, zero should be returned.
o totalSurfaceArea: Returns a double representing the total surface areas for all
RingTorus objects in the list. If there are zero RingTorus objects in the list, zero should
be returned.
o totalVolume: Returns a double representing the total volumes for all RingTorus
objects in the list. If there are zero RingTorus objects in the list, zero should be returned.
Project: RingTorus with JUnit Tests – Part 3 Page 7 of 9
Page 7 of 9
o averageDiameter: Returns a double representing the average diameter for all
RingTorus objects in the list. If there are zero RingTorus objects in the list, zero should
be returned.
o averageSurfaceArea: Returns a double representing the average surface area for
all RingTorus objects in the list. If there are zero RingTorus objects in the list, zero
should be returned.
o averageVolume: Returns a double representing the average volume for all RingTorus
objects in the list. If there are zero RingTorus objects in the list, zero should be returned.
o toString: Returns a String (does not begin with
) containing the name of the list
(which can change depending on the name of the list passed as a parameter to the
constructor) followed by various summary items: number of RingToruses, total surface
area, total volume, average surface area, and average volume. Use “#,##0.0##” as the
pattern to format the double values. Below is an example of the formatted String
returned by the toString method, where the name of the list (name field) is
RingTorus Test List and the array of RingTorus objects contains the three
examples described above (top of page 3). —– Summary for RingTorus Test List —–
Number of RingToruses: 3
Total Diameter: 445.98 units
Total Surface Area: 186,955.724 square units
Total Volume: 2,868,020.119 cubic units
Average Diameter: 148.66 units
Average Surface Area: 62,318.575 square units
Average Volume: 956,006.706 cubic units
o getList: Returns the array of RingTorus objects (the second field above).
o addRingTorus: Returns nothing but takes three parameters (label, large radius, and
small radius), creates a new RingTorus object, and adds it to the RingTorusList object in
the next available location in the RingTorus array. Be sure to increment the int field
containing the number of RingTorus objects in the RingTorusList object.
o findRingTorus: Takes a label of a RingTorus as the String parameter and returns the
corresponding RingTorus object if found in the RingTorusList object; otherwise returns
null. Case should be ignored when attempting to match the label.
o deleteRingTorus: Takes a String as a parameter that represents the label of the
RingTorus and returns the RingTorus if it is found in the RingTorusList object and
deleted; otherwise returns null. Case should be ignored when attempting to match the
label. When an element is deleted from an array, elements to the right of the deleted
element must be shifted to the left. After shifting the items to the left, the last RingTorus
element in the array should be set to null. Finally, the number of elements field must be
decremented.
o editRingTorus: Takes three parameters (label, large radius, and small radius), uses
the label to find the corresponding the RingTorus object in the list. If found, sets the
large radius and small radius fields to the values passed in as parameters, and returns true.
If not found, returns false.
(Note that the label should not be changed by this method.)
o findRingTorusWithLargestVolume: Returns the RingTorus with the largest
volume; if the list contains no RingTorus objects, returns null.
Project: RingTorus with JUnit Tests – Part 3 Page 8 of 9
Page 8 of 9
Code and Test: Some of the methods above require that you use a loop to go through the objects
in the array. You should implement the class below in parallel with this one to facilitate testing.
That is, after implementing one to the methods above, you can implement the corresponding test
method in the test file described below.
• RingTorusListTest.java (new for Part 3) – Consider implementing this file in parallel with its
source file, RingTorusList.java, which is described above this class.
Requirements: Create a RingTorusListTest class that contains a set of test methods to test each
of the methods in RingTorusList.
Design: Typically, in each test method, you will need to create an instance of RingTorusList, call
the method you are testing, and then make an assertion about the expected result and the actual
result (note that the actual result is usually the result of invoking the method unless it has a void
return type). You can think of a test method as simply formalizing or codifying what you have
been doing in interactions to make sure a method is working correctly. That is, the sequence of
statements that you would enter in interactions to test a method should be entered into a single
test method. You should have at least one test method for each method in RingTorusList.
However, if a method contains conditional statements (e.g., an if statement) that results in more
than one distinct outcome, you need a test method for each outcome. For example, if the method
returns boolean, you should have one test method where the expected return value is false and
another test method that expects the return value to be true. Also, each condition in boolean
expression must be exercised true and false. Collectively, these test methods are a set of test
cases that can be invoked with a single click to test all the methods in your RingTorusList class.
Code and Test: A good strategy would be to begin by writing test methods for those methods in
RingTorusList that you “know” are correct. By doing this, you will be able to concentrate on the
getting the test methods correct. That is, if the test method fails, it is most likely due to a defect
in the test method itself rather the RingTorusList method being testing. As you become more
familiar with the process of writing test methods, you will be better prepared to write the test
methods for the new methods in RingTorusList. Be sure to call the RingTorusList toString
method in one of your test cases so that the grading system will consider the toString method to
be “covered” in its coverage analysis. Remember that when a test method fails, you can set a
breakpoint in a JUnit test method and run the test file in Debug mode. Then, when you have an
instance in the Debug tab, you can unfold it to see its values or you can open a canvas window
and drag items from the Debug tab onto the canvas. You can also step-in to the method being
called by the test method and then single-step through it, looking for the error.
Finally, when comparing two arrays for equality in JUnit, be sure to use Assert.assertArrayEquals
rather than Assert.assertEquals. Assert.assertArrayEquals will return true only if the two arrays
are the same length and the elements are equal based on an element-by-element comparison using
the equals method.
Project: RingTorus with JUnit Tests – Part 3 Page 9 of 9
Page 9 of 9
The Grading System
When you submit your files (RingTorus.java, RingTorusTest.java, RingTorusList.java, and
RingTorusListTest.java), the grading system will use the results of your test methods and their level of
coverage of your source files as well as the results of our reference correctness tests to determine your
grade. In this project, your test files should provide method, statement, and condition coverage. Each
condition in your source file must be exercised both true and false. See below for a description of how to
test a boolean expression with multiple conditions. To see your code coverage in Web-CAT, on “Your
Assignment Submission Results” page, in “File Details”, click on your source file and look for any
highlighted lines of code. Hover your mouse on the highlighted source code, to see the hint about what
was not covered. Example of hints you might see include: (1) This line was never executed by your tests.
(2) Not all possibilities of this decision were tested. Remember that when you have N simple conditions
combined, you must test all N+1 possibilities.
Note For Testing the equals Method
Perhaps the most complicated method to test is the equals method in RingTorus. This method has three
conditions in the boolean expression that are &&’d. Since Java (and most other languages) uses short-cut
logic, if the first condition in an && is false, the &&’d expression is false. This means that to test the
second condition, the first conditions must be true. Furthermore, to test the third conditions both the first
and second conditions must be true. To have condition coverage for the equals method, you need the four
test cases where the three conditions evaluate to the following, where T is true, F is false, and X is don’t
care (could be true or false):
FXX – returns false
TFX – returns false
TTF – returns false
TTT – returns true
Note For Testing the Methods with Two &&’d Conditions
Your setSmallRadius and setLargeRadius methods likely each have two conditions in the boolean
expression that are &&’d. Since Java (and most other languages) uses short-cut logic, if the first
condition in an && is false, the &&’d expression itself is false (without considering the second
condition). This means that to test the second condition, the first condition must be true. To have
condition coverage for the equals method, you need the three test cases where the two conditions evaluate
to the following, where T is true, F is false, and X is don’t care (could be true or false):
FX – returns false
TF – returns false
TT – returns false