cs102-F2020-practical3-starter

Table of Contents

• Objectives
• Introduction
• Continuous Learning
• Assignment Reminders
• Accessing the Assignment
• Practical Assignment Tasks
  • Installing Programs that Support Python Programming
  • Using Iteration to Construct a List of Ordered Pairs Containing Factorial Numbers
  • Running a Test Suite for a Factorial Number Creation Program
  • Reflecting on the Practical Assignment
• Automated Checks with GatorGrader
• Assignment Assessment
• Advance Feedback on an Assignment
• Discussion of a Graded Assignment
• Additional Resources
  • System Commands
• Non-Interactive Docker Commands
• Commands for an Interactive Docker Shell
• Upgrading the Docker Container
  • Downloading Project Updates
  • Using GitHub Actions
  • System Requirements
  • Reporting Problems
  • Receiving Assistance

Objectives

The learning objectives for this practical assignment are as follows:

• To transfer files from your laptop to your GitHub repository
• To use your text editor to manipulate code blocks in a Markdown file
• To use your text editor to manipulate code blocks in a Python file
• To use a Docker container to run the automated checks performed by GatorGrader
• To use a terminal window to run a Python program and observe its output
• To use a text editor and a terminal window to add functions to a Python program
• To use a terminal window to run test cases in a Pytest test suite
• To extend a program segment with iteration and conditional logic into a complete program
• To use lists and tuples to store the results from mathematical calculations
• To pack content into and unpack content out of the list and tuple discrete structure

Introduction

Designed for use with GitHub Classroom and GatorGrader, this repository contains a practical assignment for an introductory computer science class that uses the Python programming language. The source code and technical writing for this assignment must pass tests set by the GatorGrader tool. When you use the git commit command to transfer your source code to your GitHub repository, GitHub Actions will initialize a build of your assignment, checking to see if it meets all of the requirements. If both your source code and writing meet all of the established requirements, then you will see a green ✔ in the listing of commits in GitHub. If your submission does not meet the requirements, a red ❌ will appear instead. Please note that, at the option of the course instructor, some checks may be run in GitHub Actions that are not run locally by the GatorGrader tool.

Continuous Learning

If you have not done so already, please read all of the relevant GitHub Guides that explain how to use many of the features that GitHub provides. In particular, please make sure that you have read the following GitHub guides: Mastering Markdown, Hello World, and Documenting Your Projects on GitHub. Each of these guides will help you to understand how to use both GitHub and GitHub Classroom.

Students who want to learn more about how to use Docker should review the Docker Documentation. Students are also encouraged to review the documentation for their text editor, which is available at VS Code. You should also review the Git documentation to learn more about how to use the Git command-line client. In addition to talking with the instructor and technical leader for your course, students are encouraged to search StackOverflow for answers to their technical questions.

As outlined in the course schedule in the course planning repository, students should also read all of the assigned readings for up to and including the week of the semester on which this practical assignment was assigned.

Assignment Reminders

• Follow each step carefully. Slowly read each sentence in this document, making sure that you precisely follow each instruction. Take notes about each step that you attempt, recording your questions and ideas and the challenges that you faced. If you are stuck, then please tell a technical leader or the course instructor what assignment step you recently completed.

• Regularly ask and answer questions. Please log into Slack at the start of the practical session and then join the appropriate channel. If you have a question about one of the steps in an assignment, then you can post it to the designated channel, discussing your questions through both Slack and the Google Meet designated for the class.

• Store your files in GitHub. Starting with this practical assignment, you will be responsible for storing all of your files (e.g., Python source code and Markdown-based writing) in a Git repository using GitHub Classroom. Please verify that you have saved your source code in your Git repository by using git status to ensure that everything is updated. You can see if your assignment submission meets the established correctness requirements by using the provided checking tools on your local computer and by checking the commits in GitHub.

• Keep all of your files. Don't delete your programs, output files, and written reports after you submit them through GitHub; you will need them again when you study for the course assessments and work on the other practical, practical, and technical challenge assignments.

• Hone your technical writing skills. Computer science assignments require to you write technical documentation and descriptions of your experiences when completing each task. Take extra care to ensure that your writing is interesting and both grammatically and technically correct, remembering that computer scientists must effectively communicate and collaborate with their team members and the student technical leaders and course instructor.

• Review the Honor Code on the syllabus. While you may discuss your assignments with others, copying source code or technical writing is a violation of Allegheny College's Honor Code.

Accessing the Assignment

To access this assignment, you should go into the #announcements channel in our Slack workspace and find the announcement that provides a link for it. Copy this link and paste it into your web browser. Now, you should accept the practical assignment and see that GitHub Classroom created a new GitHub repository for you to access the assignment's starting materials and to store the completed version of your assignment. Specifically, to access your new GitHub repository for this assignment, please click the green "Accept" button and then click the link that is prefaced with the label "Your assignment has been created here". If you accepted the assignment and correctly followed these steps, you should have created a GitHub repository with a name like Allegheny-Computer-Science-102-Fall-2020/computer-science-102-fall-2020-practical-3-gkapfham. Unless you provide the course instructor with documentation of the extenuating circumstances that you are facing, not accepting the assignment means that you automatically receive a failing grade for all of its components.

Before you move to the next step of this practical assignment, please make sure that you read all of the content on the web site for your new GitHub repository, paying close attention to the technical details about the commands that you will type and the output that your program must produce. Now you are ready to download the starting materials to your practical computer. Click the "Clone or download" button and, after ensuring that you have selected "Clone with SSH", please copy this command to your clipboard. To enter into your course directory directory you should now type cd cs102F2020. Next, you can type the either ls (on either MacOS or Linux) or dir (on Windows 10 Pro or Windows 10 Enterprise) and see that there are no files or directories inside of this directory. By typing git clone in your terminal and then pasting in the string that you copied from the GitHub site you will "download" all of the code for this assignment. For instance, if the course instructor ran the git clone command in the terminal, it would look like:

git clone git@github.com:Allegheny-Computer-Science-102-F2020/computer-science-102-fall-2020-practical-3-gkapfham.git

After this command finishes, you can use cd to change into the new directory. If you want to "go back" one directory from your current location, then you can type the command cd ... Finally, please continue to use the cd and ls commands to explore the files that you automatically downloaded from GitHub. If one of the aforementioned commands does not work correctly, then it is possible that your terminal window is not up-to-date or not configured correctly. In this case, please share your specific error messages with the instructor, ultimately working to master the use of terminal commands. What files and directories do you see? What do you think is their purpose? Spend some time exploring, telling your discoveries to a student technical leader.

Practical Assignment Tasks

Installing Programs that Support Python Programming

If you have not done so already, then, in order to implement a full-fledge Python program, you need to install the Poetry tool for dependency management and packaging of Python programs. After ensuring that you have Python 3.8 installed on your laptop through Pyenv, please follow the installation instructions for Poetry. For instance, you are using either MacOS or Linux you need to type the following command in your terminal window curl -sSL https://raw.githubusercontent.com/python-poetry/poetry/master/get-poetry.py | python. Importantly, this command will only work if you have already installed a program called curl. If you are using Windows 10 Pro then you will need to follow the PowerShell installation instructions on Poetry's web site. With that said, if you are not able to install Python 3.8.5 and Poetry on your laptop, then you can use the versions of these programs that are available in the provided Docker container.

Now, making sure that you are in your "home base" directory for this practical assignment, you need to install the dependencies for the factorialmaker program that you will implement, debug, and observe. To complete this step you need to type cd factorialmaker and then poetry install. What output did this command produce? What do you think that this step did? Why is important to type these commands? Make sure that you know the answers to these question before moving onto the next step of the assignment. Finally, please remember that when you want to run gradle grade you must be in the "home base" directory for this practical assignment. However, when you want to run the Python program you need to be in the directory called factorialmaker.

Using Iteration to Construct a List of Ordered Pairs Containing Factorial Numbers

For this practical assignment you are going to design, implement and test a program that, for a given input integer number, computes the factorial of that number and the factorial of all numbers up to that number, starting at one. This assignment will required you to combine your knowledge of functions, conditional logic, iteration, sequences, ordered pairs, and tuples, to create a single cohesive Python program that you implement in an industry-standard fashion. For instance, when you run the completed version of the Python program with the command poetry run python factorialmaker --iterative --number 5 it will produce the following output:

Calculating 5! and returning all numbers in the computation of 5! 🛫

  Should I use an iterative function? Yes

  Here is the output from the iterative function.

   Factorial values for 5! = [(1, 1), (2, 2), (3, 6), (4, 24), (5, 120)]
   Unpacking at end of list to determine 5! = 120
   The returned ordered pair shows that 5! = 120

Wow, computing factorial numbers is demanding! 😂

If you search the provided Python source code for the TODO markers, you will see that it does not include all of the source code needed to produce the program's expected output. For instance, you will need to implement a function in the factorial.py file that has the following signature: def multiply(values: List[int]) -> int. The purpose of this function is to multiply together all of the integer values inside of the provided input list and to then return that integer value. You will also need to implement a function in factorial.py that has the signature def factorial_iterative(number: int) -> Tuple[Tuple[int, int], List[Tuple[int, int]]]. The purpose of this function is to use an iteration construct compute factorial numbers given an input integer number called number. Specifically, this function should return two values, the first of which contains a tuple consisting of an int that contains number and number! and another tuple containing the ordered pairs of all the factorial numbers up to and including number!.

Perhaps the best way to understand the desired behavior of this second function is to examine the output in the above fenced code block. For instance, the output illustrates that the second output of this function should be a tuple that contains the ordered pairs of all the factorial numbers up to and including the number!, as see by this line in the output [(1, 1), (2, 2), (3, 6), (4, 24), (5, 120)]. Can you see how this is a list of ordered pairs? Specifically, the first value in these ordered pairs is the input to a factorial function and the second is the result of performing the computation for that number. That is, the ordered pair (3,6) means that 3! = 6 since 3 * 2 * 1 = 6. Similarly, the ordered pair (4, 24) means that 4! = 24 because 4 * 3 * 2 * 1 = 24.

Although you are only required to add the source code for the functions in the factorial.py file, you should take extra care to review the test suite for this file, which is tests/test_factorial.py. Do you understand how these test cases work and why they were implemented? Could you write your own test case to better test the functions that are provided inside of the factorial.py file? You should also make sure that you understand the functions implemented in the display.py file, specifically paying attention to the functions called display_factorial_unpack and display_factorial_pair. Can you explain how these functions are indexing the discrete structures provided in their input to create the appropriate output? You should also follow the TODO markers in the __main__.py file to, for example, add the correct command-line argument to the program and call the correct functions for computing the factorial numbers and displaying them in the terminal window. Although it is not a requirement for this assignment, you should also consider adding in a recursive implementation of the factorial function, ensuing that a person can request its use through a new --recursive argument provided on the command-line of the program.

Running a Test Suite for a Factorial Number Creation Program

If you look in the Python file called factorialmaker/tests/test_factorial.py you will see that it contains several test cases that call the functions in the Python program in an attempt to ensure that they are working correctly. Please take time to review each of these test cases and work to understand how they are testing the functions in the file called factorial.py. Can you explain the purpose of the different test cases for the function in the factorial.py file? Finally, if your Python program is correct, you should be able to run the test suite by typing poetry run pytest and see that it produces the following output:

=========================== test session starts ============================
platform linux -- Python 3.8.5, pytest-5.4.3, py-1.9.0, pluggy-0.13.1
rootdir: /home/gkapfham/working/teaching/github-classroom/Allegheny-Computer-Science-102-F2020/solutions/cs102-F2020-practical3-solution/factorialmaker
collected 7 items

tests/test_factorial.py .......                                      [100%]

============================ 7 passed in 0.02s =============================

Reflecting on the Practical Assignment

Once you have finished both of the previous technical tasks, use your text editor to answer all of the questions in the writing/reflection.md file. For instance, you should provide the output of the Python program in a fenced code block, explain the meaning of the three provided commands, and answer all of the other questions about your experiences in completing this practical assignment.

Automated Checks with GatorGrader

In addition to meeting all of the requirements outlined in this assignment sheet, your submission must pass the following checks that GatorGrader automatically assesses:

If GatorGrader's automated checks pass correctly, the tool will produce the output like the following in addition to returning a zero exit code (which you can access by typing the command echo $?). You will need to run GatorGrader in a Docker container by following the steps in the Using Docker section.

• The command cd factorialmaker; poetry install; poetry run python factorialmaker --iterative --number 5; cd .. executes correctly
• The factorial.py in factorialmaker/factorialmaker has at least 2 multiple-line Python comment(s)
• The factorial.py in factorialmaker/factorialmaker has at least 7 single-line Python comment(s)
• The factorial.py in factorialmaker/factorialmaker has exactly 0 of the TODO fragment
• The file factorial.py exists in the factorialmaker/factorialmaker directory
• The file __main__.py exists in the factorialmaker/factorialmaker directory
• The file reflection.md exists in the writing directory
• The file test_factorial.py exists in the factorialmaker/tests directory
• The __main__.py in factorialmaker/factorialmaker has at least 2 multiple-line Python comment(s)
• The __main__.py in factorialmaker/factorialmaker has at least 4 single-line Python comment(s)
• The __main__.py in factorialmaker/factorialmaker has exactly 0 of the TODO fragment
• The reflection.md in writing has at least 2 of the code tag
• The reflection.md in writing has at least 400 word(s) in total
• The reflection.md in writing has exactly 0 of the Add Your Name Here fragment
• The reflection.md in writing has exactly 0 of the TODO fragment
• The reflection.md in writing has exactly 10 of the heading tag
• The reflection.md in writing has exactly 3 of the code_block tag
• The repository has at least 5 commit(s)
• The test_factorial.py in factorialmaker/tests has at least 6 multiple-line Python comment(s)
• The test_factorial.py in factorialmaker/tests has exactly 0 of the TODO fragment

        ┏━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
        ┃ Passed 20/20 (100%) of checks for cs102-F2020-practical3! ┃
        ┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛

Assignment Assessment

Again taking inspiration from the principles of specification-based grading, the grade that a student receives on either a practical assignment or a technical challenge will be based on whether or not it meets the standards for technical work in the fields of software engineering and discrete structures as evidenced by:

• GitHub Actions Build Status of Either ✔ or ❌: Your work will receive a ✔ if the last before-the-deadline build in GitHub Actions passes and a ✔ appears in the GitHub commit log instead of an ❌. The build status reported by GitHub Actions will only be a ✔ if the Python source code and technical writing in the GitHub repository pass all of both the GatorGrader checks and any additional checks.

Advance Feedback on an Assignment

Students who wish to receive feedback on their work for any course assignment should first open an issue on the issue tracker for their assignment's GitHub repository, giving an appropriate title and description for the type of feedback that you would like the course instructor to provide. After creating this issue, you will see that GitHub has created a unique web site that references it. To alert the course instructor to the fact that the issue was created and that you want feedback on your work, please send it to him by a Slack direct message at least 24 hours in advance of the project's due date. After the instructor responds to the issue, please resolve all of the stated concerns and participate in the discussion until the issue is resolved and ultimately marked as closed.

Discussion of a Graded Assignment

Students who wish to receive feedback on their work for any graded course assignment should leave question in the same region of Github where the course instructor submitted the assignment's grade. For example, if the instructor submits your grade to a pull request in your repository for a practical assignment, then you should ask questions about your grade in that pull request, bearing in mind the need to @-mention the course instructor in the body of your comment. Students can continue to discuss the graded assignment with the course instructor until they understand all the technical topics that were the focus of the particular assignment.

Additional Resources

System Commands

This project invites students to enter system commands into a terminal window. This assignment uses Docker to deliver programs, such as gradle and the source code and packages needed to run GatorGrader, to a students' computer, thereby eliminating the need for a programmer to install them on their development workstation. Individuals who do not want to install Docker can optionally install of the programs mentioned in the Project Requirements section of this document.

Non-Interactive Docker Commands

Once you have installed Docker Desktop, with MacOS and Linux you can use the following docker run command to start gradle grade as a containerized application, using the DockaGator Docker image available on DockerHub.

docker run --rm --name dockagator \
  -v "$(pwd)":/project \
  -v "$HOME/.dockagator":/root/.local/share \
  gatoreducator/dockagator

The aforementioned command will use "$(pwd)" (i.e., the current working directory) as the project directory and "$HOME/.dockagator" as the cached GatorGrader directory. Please note that both of these directories must exist, although only the project directory must contain something. Generally, the project directory should contain the source code and technical writing for an assignment, as provided to a student by the instructor through GitHub. Additionally, the cached directory should not contain anything other than directories and programs created by DockaGator, thus ensuring that they are not otherwise overwritten during the completion of the assignment.

To ensure that the previous command will work correctly, you should create the cache directory by running the command mkdir $HOME/.dockagator on the MacOS and Linux operating systems. However, if you are using the Windows operating system then you will instead need to type the command mkdir %HomeDrive%%HomePath%/.dockagator. Finally, since the above docker run command does not work correctly on the Windows operating system, you will need to instead run the following command to adapt to the differences in the cmd terminal window:

docker run --rm --name dockagator \
  -v "%cd%:/project" \
  -v "%HomeDrive%%HomePath%/.dockagator:/root/.local/share" \
  gatoreducator/dockagator

Please note that not all version of the Windows terminal window will correctly recognize the use of the %cd% and %HomeDrive%%HomePath% variables. In this case, you should substitute the actual directory for a specific course assignment for the %cd% variable and the drive letter that contains the .dockagator directory for the %HomeDrive%%HomePath% variable. Finally, the Windows terminal window may not work correctly when you attempt to run a multi-line command. In this case, you should break up the aforementioned four-line command into separate lines, like docker run --rm --name dockagator and -v "%cd%:/project" and then connect them into a single long line that you separate by a single space. Here is an example of what the long command would look like, again assuming that the Windows cmd terminal correctly interprets the %cd% and %HomeDrive%%HomePath% variables:

docker run -it --rm --name dockagator -v "%cd%:/project" -v "%HomeDrive%%HomePath%/.dockagator:/root/.local/share" gatoreducator/dockagator /bin/bash

Here are some additional commands that you may need to run when using Docker:

• docker info: display information about how Docker runs on your workstation
• docker images: show the Docker images installed on your workstation
• docker container list: list the active images running on your workstation
• docker system prune: remove many types of "dangling" components from your workstation
• docker image prune: remove all "dangling" docker images from your workstation
• docker container prune: remove all stopped docker containers from your workstation
• docker rmi $(docker images -q) --force: remove all docker images from your workstation

Commands for an Interactive Docker Shell

Since the above docker run command uses a Docker images that, by default, runs gradle grade and then exits the Docker container, you may want to instead run the following command so that you enter an "interactive terminal" that will allow you to repeatedly run commands within the Docker container. Don't forget that, if you are using the Windows operating system, then you will need to use a different command to run Docker, as explained previously in this document. Importantly, the command that you type if you are a Windows user should still contain the -it at the start of the docker run and the /bin/bash at the end of the command. However, the other components of this command need to be customized for the Windows operating system.

If you use either MacOS or Linux, then this is the command that you would run to enter into the interactive terminal provided by a Docker container:

docker run -it --rm --name dockagator \
  -v "$(pwd)":/project \
  -v "$HOME/.dockagator":/root/.local/share \
  gatoreducator/dockagator /bin/bash

If you use Windows, then this is the command that you would run to enter into the interactive terminal provided by a Docker container:

docker run -t --rm --name dockagator \
  -v "%cd%:/project" \
  -v "%HomeDrive%%HomePath%/.dockagator:/root/.local/share" \
  gatoreducator/dockagator /bin/bash

Once you have typed this command, you can use the GatorGrader tool in the Docker container by typing the command gradle grade in your terminal. Running this command will produce a lot of output that you should carefully inspect. If GatorGrader's output shows that there are no mistakes in a course assignment, then your source code and technical writing are passing all of the automated baseline checks. However, if the output indicates that there are mistakes, then you will need to understand what they are and then try to fix them.

Remember, to correctly run any of the commands mentioned in this guide, you must be in the main (i.e., "home base") directory for a course assignment where the build.gradle file is located.

Upgrading the Docker Container

If the course instructor provides a new version of the Docker container called gatoreducator/dockagator and you want to receive it immediately, you must first delete the existing Docker container on your laptop by running the command docker rmi gatoreducator/dockagator. Next, you can re-run one of the aforementioned Docker commands, like the following one, which would work on MacOS or Linux:

docker run -it --rm --name dockagator \
  -v "$(pwd)":/project \
  -v "$HOME/.dockagator":/root/.local/share \
  gatoreducator/dockagator /bin/bash

Please note that if you attempt to run gradle grade in an updated Docker container it is possible that the command will execute incorrectly if you previously used GatorGrader with a Docker container that featured a different version of the Python programming language. In this situation, you should delete the directories inside of the .dockagator directory and then again attempt to run the gradle grade command inside of the Docker container. Specifically, you will need to delete directories in .dockagator that are normally called gatorgrader, virtualenv, and virtualenvs.

Downloading Project Updates

If GatorGrader's maintainers push updates to this sample assignment and you received it through GitHub Classroom and you would like to also receive these updates, then you can type this command in the main directory for this assignment:

git remote add download git@github.com:Allegheny-Computer-Science-102-F2020/cs102-F2020-practical3-starter/

You should only need to type this command once; running the command additional times may yield an error message but will not negatively influence the state of your Git repository. Now, you are ready to download the updates provided by the GatorGrader maintainers by typing this command:

git pull download master

This second command can be run whenever the maintainers needs to provide you with new source code for this assignment. However, please note that, if you have edited the files that we updated, running the previous command may lead to Git merge conflicts. If this happens, you may need to manually resolve them with the help of the instructor or a student technical leader. Finally, please note that the Gradle plugin for GatorGrader will automatically download the newest version of GatorGrader.

Using GitHub Actions

This assignment uses GitHub Actions to automatically run GatorGrader and additional checking programs every time you commit to your GitHub repository. The checking will start as soon as you have accepted the assignment — thus creating your own private repository — and the course instructor and/or GitHub enables GitHub Actions on it. If you do not see either a yellow ● or a green ✔ or a red ❌ in your listing of commits, then please ask the instructor to see whether or not GitHub Actions was correctly enabled.

System Requirements

This assignment was developed to work with the following software and versions:

• Docker Desktop
• Operating Systems
  • Linux
  • MacOS
  • Windows 10 Pro
  • Windows 10 Enterprise
• Programming Language Tools
  • Gradle 6.6
  • MDL 0.5.0
  • Python 3.7 or 3.8

Reporting Problems

If you have found a problem with this assignment's provided source code or documentation, then you can go to the Computer Science 102 Fall 2020 Planning Repository and raise an issue. If you have found a problem with the GatorGrader tool and the way that it checks your assignment, then you can also raise an issue in that repository. To ensure that your issue is properly resolved, please provide as many details as is possible about the problem that you experienced. Individuals who find, and use the appropriate GitHub issue tracker to correctly document, a mistake in any aspect of this assignment will receive extra credit towards their grade for the course.

Receiving Assistance

If you are having trouble completing any part of this project, then please talk with either the course instructor or a student technical leader during the course session. Alternatively, you may ask questions in the Slack workspace for this course. Finally, you can schedule a meeting during the course instructor's office hours.