MP0: Triple Crown

Before starting MP0 there are two pieces of setup and preparation to complete:

We will provide time during Lab 1 to complete these steps, but you are welcome to go through them beforehand if you are raring to get going.

Use this GitHub Classroom invitation link to fork your copy of MP0. Once your repository has been created, import it into IntelliJ following our assignment Git workflow guide.

All three programs need to be completed. The structure of each is similar:

Your goal is to correctly implement the missing methods so that all of the tests pass. Doing so will earn you almost full credit on the assignment—but see the section on style below.

A core task when approaching any programming assignment or task is to identify what you need to do. For MP0 there are three—and only three—functions that you need to change. Begin by identifying those functions and understanding their requirements. This will go a long way to helping you complete the MP.

Your initial clone of MP0 will receive 0 points. That’s intentional! But once you fix a few small bugs you’re score will improve quickly. In fact, it’s possible to get 40 points for code that doesn’t pass any of the tests—as long as it compiles and passes the checkstyle tests.

Use IntelliJ to help you here. It can intelligently identify problems with your MP and guide you toward solutions.

We have provided you with testing suites that you can use to perform iterative test-driven development. You should integrate this process into your normal CS 125 Git workflow. Here’s how that works:

In general the fewer lines of code you write before running a test, the better. When you are starting out, it is easy to introduce bugs into your code. Bugs are easiest to catch one-by-one, and so the fewer lines of untested code the more likely you are to identify errors in your logic or implementation.

The course staff is ready and willing to help you every step of the way! Please come to office hours, or post on the forum when you need help. You should also feel free to help each other, as long as you do not violate the academic integrity requirements.

Follow the instructions from the submitting portion of the CS 125 workflow instructions. Note that the first time you do this you’ll want to pay careful attention to the common submission pitfalls, particularly if your submission doesn’t show up when you think it should.

You should carefully review the test cases in LCMTest.java, MinimumOfFirstNTest.java, and QuizzerTest.java. The MP0 testing suite follows a common pattern where functions are tested against pre-computed inputs and outputs. So, for example, when testing MinimumOfFirstNTest.java, we compute the correct answer for a small subset of test cases and use this to determine whether your solution works in all cases.

Automated testing is a hugely important part of modern software development. Just like computers are good at running programs, they are also good at running programs to debug other programs. Independently developing a method and the function that tests it allows the two to support each other. The test may find errors in the method, and, the method may also identify errors in the test.

When possible, we provide you with both simple test cases using a small number of select inputs and exhaustive test cases that use many randomly-generated inputs. The former should be used during iterative development. The latter are used during grading. Note that the simple test cases are not used during grading. So if you pass them but not the full test suite you will not receive credit. The local autograder we provide will be able to help you estimate your score before you submit.

We have provided you with an autograding script that you can use to estimate your current grade as often as you want. The IntelliJ project a run configuration called "Grade MP0" that will run the autograder for MP0.

Unless you have modified the test cases or autograder configuration files, the autograding output should approximate the score that you will earn when you submit. If you modify our test cases or the autograding configuration, all bets are off. You may also lose points if your solution runs too slowly and exceeds the testing timeouts 1.

90 points on MP0 are for correctly implementing the required functions. The other 10 points are for style. Writing readable code according to a style guideline is extremely important, and we are going to help you get into this habit right from the start. Every software development company and most active open-source projects maintain style guidelines. Adhering to them will help others understand and integrate your contributions.

We have configured the checkstyle plugin to enforce a variant of the Sun Java coding style. IntelliJ should naturally generate code that meets this standard. So you should not have to fight with IntelliJ too much to avoid checkstyle violations.

However, the checkstyle plugin does require you to add Javadoc comments, and also avoid the use of so-called magic numbers. You may find these requirements a bit annoying at first, but we trust that you will get used to them.