PA3 Testing Infrastructure

For this assignment, you can use this repository as a starting point for writing tests for your implementation of PA3. You will be submitting some of these files along with your implementation so that our autograder can correctly run tests on your compiler.

Before you begin

Copy over the tests folder to your implementation. You can simply use cp (or copy on Windows) to move this folder to where your implementation is located.

Once you've done that, take a moment to familiarize yourself with the contents of the tests folder.

Contents of tests folder

pa3-visible.test.ts

The autograder will overwrite this file

We are making some of the tests that our autograder runs on your submission visible for you. Use these as an example of how to write tests, but passing these tests does not mean your implementation is complete. Make sure to write plenty of other tests.

asserts.test.ts

The autograder will overwrite this file

This file contains the assert functions we use for testing. You should not change any definitions in this file since we won't be using any version you upload. The pa3-visible tests file should provide good example of how to use the assert functions defined here. We use for different functions for testing your implementation:

• assertPrint: This function runs a program (which calls print) and compares the output of printing to the expected output.
• assertFail: This functions runs a program and asserts that it fails at runtime, raising an exception starting with RUNTIME ERROR:
• assertTC: This function type-checks a program and compares the type of the last statement to an expected type.
• assertTCFail: This function type-checks a program and asserts that it fails at type-checking, raising an exception starting with TYPE ERROR:

import-object.test.ts

The autograder will overwrite this file

This is the import object defined for the purpose of testing. It's almost identical to the import object you find in webStart, but printing here adds to a string buffer instead of outputting to stdout. You also should not change any definitions in this file.

helpers.test.ts

You must include this file when submitting

This is the only file where you will need to make changes to get the tests to run on your compiler. Make sure to fill out the defintions in this file according to your implementation. You will need to change:

• function typeCheck(source: string) : Type (Type-check a program)
• async function run(source: string) (Run a program)

Note that you can use any definition of types, ast, etc that you like in your program. You just have to convert to our definition of Type for testing.

For the purposes of testing, remember that the type of a program is the type of its last expression statement (or "none" if the last statement isn't an expression).

Running Tests

You should be able to run our tests (and any additional tests you write) using the command:

npm test

The sample package.json provided here has a test command that's the same as we used for the recommended starter code for PA2; you can probably just re-use the same one as for PA2, but we provide this for reference. (Also, if you just check out this repository and run npm install then npm test, you can see what test output looks like).