Instructions for CharStringReturnInt Testing Template

Transcription

1 Instructions for CharStringReturnInt Testing Template Overview These instructions will help you implement a code magnet microlab where the method is passed a character and string parameters and returns an integer type. There are two steps in this process: 1. Implement the desired method and testing harness outside of WAGS (Web Automated Grading System) and 2. Implement the code magnet lab in WAGS. This is illustrated with the countlargercharacters method that counts the number of characters in the given string that are larger than the given character. You will change the countlargercharacters method to a method of your choice that has the same signature: input a character and string parameter and returns an integer type. The zip file CharStringReturnInt.zip contains four Java files: 1. CharStringReturnIntTest.java this is heart of the test program and should not require any modification by the developer. This will be uploaded as the test file when using the magnet creation page in WAGS. 2. ParamDataAndInvocations.java the parameter values are specified as an array of characters and an array of strings in this file. Two methods are used to invoke a correct version of the method and the student version of the method. This file will be modified as described in the steps outlined below and uploaded as a helper file when using the magnet creation page in WAGS. 3. CorrectMethod.java this file contains a correct version of the method being implemented as a code magnet method; it will be used to generate a correct return value for comparison with the method created in the code magnet lab. This file will be modified as described in the steps outlined below and uploaded as a helper file when using the magnet creation page in WAGS. 4. Student.java this file contains the method to be developed as a code magnet microlab; it is only used to test the testing environment

2 independently of the WAGS system. DO NOT upload this file when you are using code magnet creation in WAGS. Step 1 To complete step one you need to do the following: Design your java method that has a character and string parameters and returns an integer; put a copy inside of CorrectMethod.java and Student.java Change the character and string values in ParamDataAndInvocations.java to match the desired test values for your method. You can include as many values as you wish; be sure to include limiting cases for the method you are developing. Change invokecorrectmethod and invokestudentmethod to call the appropriate method in the CorrectMethod and Student classes, respectively. Use your favorite IDE to test this testing framework. Upload the four files (CharStringReturnIntTest.java, ParamDataAndInvocations.java, CorrectMethod.java, Student.java) into the IDE Set the first main method parameter value to any integer value of your choice; this is a nonce value that will be printed after testing is completed Run the test program and insure you get the expected results Step 2 To create a code magnet lab you need to put the desired method the students will construct into standard form and then add alternative magnets as appropriate. This is illustrated using the countlargercharacters method included in the download files. Standard form means changing the desired method in the following ways: All control statements, such as if, else, while, for, are required to have a body enclosed in braces, even if the body is a single statement. Put every declaration/initialization/statement on a separate line. Put the header of every control statement on a separate line ending in an opening brace; put every statement in the body on a separate line; put

3 the closing brace on a separate line. NOTE: our parser does not currently handle switch statements, so please use if statements. Most of these are the standard for Eclipse auto-formatting NOT in standard form public int countlargercharacters(char ch, String s) { for(int index = 0; index < s.length();index++) { if(s.charat(index) > ch) count++; CORRECT standard form public int countlargercharacters(char ch,string s){ for(int index = 0; index<s.length();index++){ if(s.charat(index) > ch){ count++; You then need to add a heading block that contains the title of the lab and a description for students who will use the lab. The format of this block is: The first line in the file opening starting a comment line with /* The title of the lab on a new line; this must be unique from other labs A blank line A description for students who will be using the lab to help their understand of the goal to be completed; this is usually multiple lines A closing comment line ending with */ Comment block for the countlargercharacters /*********************************** Count Larger Characters Given a target character and a string, count the total number of characters in the string that are greater than the given character value. ***********************************/ STEP 2A Create a code magnet lab where all magnets are used to construct a correct solution.

4 Put the desired method into standard form, including the header block, do not put inside an enclosing class; name the file appropriately; we used countlargercharacters.java for the example provided. Log onto the WAGS system using your account; in the top toolbar select Magnet Creation from the Admin pull down menu. Go to the bottom right side of the screen and select Choose File under the parse file option; navigate to the java file in standard form and select it. Press the parse button once the file is selected; the text boxes on the right side of the screen should be filled in. Go to choose file for the Testing class and upload the file CharStringReturnIntTest.java Go to choose file for the Helper class and upload the file CorrectMethod.java Add another helper class and upload ParamDataAndInvocations.java Press create and test your code magnet lab to ensure it works correctly. STEP 2B It is often desirable to add alternative magnets so that students must choose between two similar magnets, such as one containing a > comparison and the other containing a >= comparison. The file with the magnet lab in standard form can be modified in the following way: duplicate the line that will become the alternative magnet then modify one of the two lines with the desired change. Here is the iterative countlargercharacters method where the alternative magnets are shown in red. public int countlargercharacters(char ch, String s){ count = 0; for(int index = 0; index <= s.length();index++){ for(int index = 0; index < s.length();index++){ if(s.charat(index) >= ch){ if(s.charat(index) > ch){ count++;

5 Add some alternative magnets to your method in standard form and then parse the new file in the magnet creation page. You should not need to change the test program or the helper files. Test your new lab and make changes as appropriate.