Assignments

• 1: Assignment 1 - Problem Statements
• 2: Assignment 2 - Unit testing
• 3: Assignment 3 - Information Literacy
• 4: Assignment 4 - Meteoric Design, Implementation, and Test

1 - Assignment 1 - Problem Statements

“Programming all too often begins without a clear understanding of the problem.”

– J.M. Yohe¹

A good problem statement has the following structure in clearly-labeled sections²:

1. Concise and precise statement of the problem.
   • Provide a summary of the problem. What is the problem you are trying to solve?
   • If appropriate, include relevant calculations or computations provided by your customer/boss/instructor.
   • Do not write the precise algorithm you will implement.
2. Clearly specified input format. Input includes function arguments, file contents, or user console input. What does the data look like? For example:
   • three integer values separated by spaces on a line.
   • each bank record consists of the id number (integer), a name (string), and current balance (a float). These values are read from a file. Each line corresponds to a single record, and the values are separated by commas.
   • the user will be prompted to enter their first name, last name, and date of birth in the console as strings.
3. Clearly specified output format.
   • Output could be printed to the screen, text written to a file, or the values returned from a function.
   • As with input, describe what does this data look like?
4. Define exceptional conditions, e.g., things you should check for (like invalid values) and what you should do if they occur. For example:
   • The user enters a float when an integer is expected. What will you do?
   • The user provides a filename to read that doesn’t exist. What will you do?
5. Sample input. This needs to be as exact and precise as possible. For example (matching #2 above):
   • 22,56,999
   • 850123456,"Bob Smith",500.00
   • First name: "Bob", Last name: "Smith", DOB: "01/02/2004"
6. Sample output. Exact and precise as possible as with the sample input.

Part A - write a problem statement

This will be completed in class.

With a partner (required): Write a problem statement using the best practices described in class. Here is the high-level problem:

Write a program where the user enters three side lengths and the program says if they can form a triangle or not. This is the Triangle Inequality Theorem.

Suppose we label the numbers a, b, and c. They can form a triangle if:
a + b ≥ c, and
b + c ≥ a, and
a + c ≥ b.

The user will input the values from the console. The three sides should be entered separately. Your program must accept the input values, produce a result, and then terminate. You may include a loop that allows the user to repeat the process multiple times before quitting. It’s up to you.

Use this plain text template to write your problem statement. You must save it as a plain .txt file, not Word or anything else.

Grading

I expect that each spec.txt will be different, and that is okay. I am looking for the completion of the problem statement sections that address the functionality required.

Rubric

• (6 pts) All elements of the template are completed. Sample input values and sample output values must include normal and exceptional behaviors.
• (1 pts) At least two exceptional conditions are specified.
• (3 pts) Correct spelling and grammar.

Submission due by Thursday, February 6

Each partner submits their team’s spec.txt to the Canvas assignment 1.A page.

Part B - Implementation

Individually create triangle.py and implement the problem you specified in spec.txt.

The goal is to warm-up your Python skills, and to see how the implementations of two people working from the same spec will be different.

You may not share code under any circumstances. Getting answers to simple Python questions from your peers is fine. Review the Syllabus section on Collaboration and Cheating for what is allowed and not allowed. If in doubt, ask me – I promise I won’t be mad if you ask.

Grading

You are graded on the correctness of your code, not the correctness of the spec.txt. If you discover an error in your spec.txt, you may communicate it with your partner.

Rubric

• (10 pts): Functionally correct implementation that (a) accepts user input according to the format in your spec, and (b) produces correct output as to whether the input can form a triangle or not for several valid input values.
• (5 pts): The program detects and handles at least two exceptional conditions you specified in spec.txt. “Handling” means it does not crash with an exception, but terminates or continues gracefully.

You will receive 0 points if your program does not run due to syntax errors or does not complete under “normal” conditions.

Submission due by Sunday, February 9

Submit your triangle.py file to the Canvas assignment 1.B page.

2 - Assignment 2 - Unit testing

Objective

The goal of this assignment is to gain more practice with the tools we have used so far, including implementing a unit test with pytest.

Setup

1. Create a new project directory named assn2/ or something similar.
   • Mac and Ubuntu on VirtualBox users: Open that directory using PyCharm as usual.
   • WSL users: Follow the setup process as the bottom of the page.
2. Download grades.py to the assn2/ folder

Instructions

The assignment is to be completed alone. Refer to the Syllabus for policies on what is allowed and what is not.

Implementation

1. Put your name at the top.
2. You may not change the main() function in any way.
3. You may add to the __main__ block to help test if you want.
4. Complete the functions calculate_average() and determine_grade() according to their docstring descriptions:
   • The docstring tells you what the function must do, the parameters passed to it, the type that must be returned, and any exceptions you need to raise.
   • You may not add any parameters, change the return type, or add to or alter the exceptions required.
   • You must not call print() or input() from these functions.

Testing

1. Create a test file for grades.py.
2. Put your name at the top of your test file in a comment.
3. Write one or more test cases in your test file for calculate_average().
   • The test case must invoke calculate_average() by providing a list, e.g., calculate_average([1,2,6]). Use assert statements to ensure the computed value is correct. You should have multiple asserts to check the calculation.
   • You must write test cases that check the exceptional conditions that raise value errors. Refer to the lab on testing for exceptions.
4. Write one or more test cases in your test file for determine_grade(). This function does not knowingly raise exceptions, so you do not need to test for them. Test only for expected output given an input.
5. Run your test file using pytest.

Rubric

• (15 pts): Your implementation of calculate_average() passes my test cases, which exercises all the details of the function’s docstring.
• (10 pts): Your implementation of determine_grade() passes my test cases, which exercises all the details of the function’s docstring.
• (15 pts): Create a control flow graph (CFG) for each of your implementations of calculate_average() and determine_grade() following the rules from class.
  • You may use an online flow chart tool such as draw.io, Canva, or Lucidchart.
  • You may draw your CFG on paper and take a picture. Ensure it is legible.
  • In both cases, export your CVG image to a PDF to submit to Canvas.
• (25 pts): Your test file can be run using pytest, has multiple test cases, and thoroughly tests the parameters, returns, computations, and exceptions raised of the functions as specified by their docstrings.
• Your assignment will receive a score of 0 pts for any of the following:
  • print() or input() statements in calculate_average() or determine_grade()
  • Changing main() in any way
  • Changing the method signature of calculate_average() or determine_grade()
  • Your code or tests fail due to syntax error.

Submission due Feb 23

Submit your grades.py, your test file, and your CFG PDF file to the Canvas assignment page.

Setup for WSL Users

You will follow this process for every project on WSL from now on.

1. Open PyCharm and select the File menu, then Close Project.
2. Select WSL on the left, then the + button to create a new project.
3. Select the ... button to pick the Project directory.
4. Pick your Ubuntu instance at the top, then navigate to home/<your_id>/seng-201/ and create a new folder (icon at the top) for assn2/.
5. Select the new directory and hit OK.
6. Click Start IDE and Connect on the screen. PyCharm will take a minute to finish configuring. It should open a new window with a main.py file showing some boilerplate code.
7. Select the File menu, then Settings.
8. Select Project: assn2 in the left pane, then click the Python Interpreter link.
9. Select the Add Interpreter link near the top right, then Add Local Interpreter.
10. Leave the default options selected and hit OK. If you see a red error message, contact the instructor.
11. OK out of the settings screen.
12. Finally, open a new Terminal within PyCharm. Type which pip. You should see something like
    • /home/<your_id>/seng-201/assn2/.venv/bin/pip, or;
    • /home/<your_id>/virtualenvs/assn2/bin/pip
    • but not /usr/bin/python
13. You will run all subsequent Terminal commands from the integrated Terminal in PyCharm.
14. run the following in the integrated Terminal:

    pip install pytest pytest-cov
    

15. Complete the setup instructions at the top of this lab.

3 - Assignment 3 - Information Literacy

Objectives

• Write effective Internet search queries and use official documentation to research answers.
• Examine and compare information from various sources to evaluate its accuracy, authority, currency, and relevance.
• Properly cite and apply the researched information to help solve software engineering problems.

Overview

Software engineers constantly use the Internet to learn how to achieve functionality and to help debug errors.

You will find plenty of wrong or misleading answers on the Internet. Who has time for that? You need to be able to discern between good sources from time wasters.

Instructions

Download and complete assignment_3.docx. Complete it with a partner in class and submit to Canvas.

Code for Task 1

Run the following Python code. You will get an error and stack trace:

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def calculate_cart_total(cart_items, tax_rate):
    """Calculate total cart cost including tax."""
    subtotal = sum(item["price"] * item["quantity"] for item in cart_items)
    return subtotal + (subtotal * tax_rate)

def display_cart_summary(cart_items, tax_rate):
    """Display a summary of the cart."""
    total_cost = calculate_cart_total(cart_items, tax_rate)
    print(f"Total cost (including tax): ${total_cost:.2f}")

def main():
    """Main function to simulate a shopping cart."""
    cart = [
        {"name": "Laptop", "price": 1000.0, "quantity": 1.0},
        {"name": "Headphones", "price": 200.0, "quantity": 2.0},
        {"name": "Mouse", "price": 50.0, "quantity": 1.0},
        {"name": "Keyboard", "price": 150.0, "quantity": 1.0},
        {"name": "Monitor", "price": 300.0, "quantity": 1.0},
        {"name": "HDMI Cable", "price": 10.0, "quantity": 2.0},
        {"name": "USB Drive", "price": "20.0", "quantity": 3.0},
        {"name": "External Hard Drive", "price": 100.0, "quantity": 1.0},
    ]
    tax_rate = 0.07  # 7% sales tax
    display_cart_summary(cart, tax_rate)

if __name__ == "__main__":
    main()

Submission due Friday Feb 28 @ 11:59pm via Canvas

Upload your completed assignment_3.docx to the Canvas assignment page.

4 - Assignment 4 - Meteoric Design, Implementation, and Test

Code resources

Submitting code or other solutions from anywhere other than your own brains is cheating.

• Can you research how to use a particular function or library such as pytest? Yes.
• Can you get code that solves all or part of your homework? No.
• When in doubt, ask. I will not be upset if you ask.

Refer to the full details in the Syllabus on Canvas.

Setup

You will complete a program to analyze the NASA Meteorite Landings dataset: https://data.nasa.gov/widgets/gh4g-9sfh. Setup

1. Download assignment4.zip and unzip it. It contains three files:
   • meteorite_landings.csv
   • meteoric.py
   • test_meteoric.py
2. Place these files in an assignment4/ directory if not done for you.
3. Open the assignment4 directory as a PyCharm project.
4. Configure pytest:
   • Mac and Ubuntu on VirtualBox users: Open that directory using PyCharm as usual.
   • Windows users: You can use either native Windows or WSL.
     • If using WSL, follow the setup process at the bottom of this page.
     • If you prefer to use native Windows, run the command pip install pytest pytest-cov from the PyCharm Terminal. Let me know if you get errors and I will help.

Implementation

1. Implement a solution in meteoric.py to the Problem Statement below.
2. Put your name at the top of meteoric.py in the module docstring.
3. You may create classes and files and use imported libraries, but these things are not necessary.
4. Your solution must adhere to the 6 rules of low-level program design. Ask if you have any questions!
5. You are free to modify the provided code, including load_data() code.
6. You will need to implement the haversine formula. You may use code from the web, but include the link to the source website in a code comment.
7. Add docstrings following our conventions to any functions, classes, and files you create.
8. The code must adhere to the PEP8 coding conventions discussed in class.

Testing

1. Add test cases to test_meteoric.py. Any additional source files you create must also have a test_*.py test.
2. All test cases must run from the CLI with pytest.
3. Use pytest --cov --cov-branch --cov-report=html to generate a branch coverage HTML report in your project directory.
4. You must achieve 90% branch coverage in all source files except for the main() function.

Rubric

• (5pts) PEP8 coding conventions followed
• (5pts) Docstring conventions followed for modules (files), classes (if any), and functions.
• (25pts) User commands are correctly implemented, including exception handling of user input errors.
• (10pts) Adherence to our 6 low level design rules.
• (15pts) Multiple test cases with proper test structure for your source code. pytest branch coverage HTML report demonstrating ≥90% branch coverage of all source code except for main().

Problem Statement

Problem outline

Write a program the analyzes the NASA Meteorite Landings dataset available at https://data.nasa.gov/widgets/gh4g-9sfh. The program runs from the Terminal/CLI. The program will have two primary capabilities. The first is to display all meteorites discovered in a given year. The second is to display the meteorite geographically closest to a provided latitude and longitude.

The program must run from the CLI as python meteoric.py <command> <argument>. See the input format and sample inputs for examples of running the program.

Input format

The program must understand the following commands:

• year <integer>: Print out the meteorite name, latitude, and longitude for all meteorites discovered in the <integer> year. It is possible that no meteorites were discovered in a given year. Example usage: python meteoric.py year 1999
• geopoint <latitude,longitude>: Print out the meteorite name, latitude, and longitude for the meteorite with the closest great-circle distance to the coordinates. Latitude is a float in the range [-90.0, 90.0]. Longitude is a float in the range [-180.0, 180.0]. Example usage: python meteoric.py geopoint 34.2257,-77.9447

The data in meteorite_landings.csv looks like this:

name,id,year,reclat,reclong
Aachen,1,1880,50.775,6.08333
Aarhus,2,1951,56.18333,10.23333
Abee,6,1952,54.21667,-113
Acapulco,10,1976,16.88333,-99.9
...

Important: a load_data() function is provided in meteoric.py that loads the data from meteorite_landings.csv into a list of lists. You do not need to validate the data in the CSV file, however, some fields may be blank if the information is missing.

Output format

• Print meteorite data to the console in a human-friendly format.
• When searching for all meteorites that were discovered in a given year the program will either: (a) display a list of meteorites discovered, or (b) display a message stating no meteorites were found for the given year.
• When searching for the closest meteorite landing from a specific location, the program will display the name (or names if two or more meteorites have an equal distance from the specified location) of the meteorite closest to the location given by the user.
• If the user fails to provide a valid command or valid arguments, the console displays an error message indicating what the user did incorrectly.

Exceptional conditions

Do not assume the <command> or <argument> are present or valid. The program must print an error message, not an exception or stack trace, if given bad arguments.

• user can put in an invalid command keyword
• user does not give an argument
• user gives an invalid data type with the year keyword
• user enters a year with no meteorite
• user inputs latitude and longitude incorrectly
• user enters multiple arguments
• user gives an out of range latitude or longitude

Sample input

1. python meteoric.py test: invalid command
2. python meteoric.py year: missing argument
3. python meteoric.py geopoint: missing argument
4. python meteoric.py year s: invalid argument
5. python meteoric.py geopoint abcdef: invalid argument
6. python meteoric.py year 1999 2001 asd: invalid arguments
7. python meteoric.py geopoint 120.884,300.475: invalid latitude and longitude
8. python meteoric.py geopoint 32.558,78.854: valid search by geopoint
9. python meteoric.py year 1818: valid search by year
10. python meteoric.py year 55: valid search by year, no meteorites match that year

Sample output

You may change these to be more precised if you like, but not less precise.

1. Invalid command and argument. Correct format is python meteoric.py <command> <argument>.

2. Invalid command and argument. Correct format is python meteoric.py <command> <argument>.

3. Invalid command and argument. Correct format is python meteoric.py <command> <argument>.

4. Invalid argument. year argument must be an integer.

5. Invalid argument. geopoint argument must be latitude,longitude.

6. Invalid command and argument. Correct format is python meteoric.py <command> <argument>.

7. Invalid argument. geopoint latitude or longitude out of range.

8. Meteorite(s) discovered closest to 32.4, 103.92:
       Guangyuan, latitude: 32.4, longitude: 105.9
   

9. Meteorite(s) discovered in 1818: 
       Seres, latitude: 41.05, longitude: 23.56667
       Slobodka, latitude: 55, longitude: 35
       Zaborzika, latitude: 50.28333, longitude: 27.68333
       Cambria, latitude: 43.2, longitude: -78.8
       Cape York, latitude: 76.13333, longitude: -64.93333
   

10. No meteorites found for the year 55.

Submission due Sunday, March 30

Upload all .py files from your project directory to Assignment 4 on Canvas.

Setup for WSL Users

1. Open PyCharm and select the File menu, then Close Project.
2. Select WSL on the left, then the + button to create a new project.
3. Select the ... button to pick the Project directory.
4. Pick your Ubuntu instance at the top, then navigate to home/<your_id>/seng-201/ and create a new folder (icon at the top) for assignment4.
5. Select the new directory and hit OK.
6. Click Start IDE and Connect on the screen. PyCharm will take a minute to finish configuring. It should open a new window with a main.py file showing some boilerplate code.
7. Select the File menu, then Settings.
8. Select Project: assignment4 in the left pane, then click the Python Interpreter link.
9. Select the Add Interpreter link near the top right, then Add Local Interpreter.
10. Leave the default options selected and hit OK. If you see a red error message, contact the instructor.
11. OK out of the settings screen.
12. Finally, open a new Terminal within PyCharm. Type which pip. You should see something like
    • /home/<your_id>/seng-201/assignment4/.venv/bin/pip, or;
    • /home/<your_id>/virtualenvs/assignment4/bin/pip
    • but not /usr/bin/python
13. You will run all subsequent Terminal commands from the integrated Terminal in PyCharm.
14. run the following in the integrated Terminal:

    pip install pytest pytest-cov
    

15. Complete the setup instructions at the top of this lab.