🐘PHP

Overview

An AutoTest V2 configuration for a PHP assignment has two stages:

• The Setup stage: this is where you setup the auto grading environment. You can install packages and upload files. This builds into an image on which all tests are executed. All the configuration here only runs once for all submissions;

• The Tests stage: this is what students will see and where you can configure all your tests that you want to run on every student’s code. Everything that you specify here is executed in the working directory of the student.

Steps are created in a “Scratch-like” block layout and can be dragged and dropped, reordered and nested to create an AutoTest program. We are continuously adding new blocks to AutoTest V2 to make it more powerful and easier.

AutoTest V2 is still available next to our original AutoTest, to start setting up an AutoTest V2 select AutoTest V2 when creating a new AutoTest. Already have an original AutoTest? You can switch to AutoTest V2 by deleting it and pressing "Select another version of AutoTest" to finally select AutoTest V2. Please note that your original AutoTest will be deleted when pressing the "Delete" button!

Developing, snapshots and publishing to students

When developing your AutoTest V2 configuration, you can continuously test your configuration on the "Test Submission".

After configuring something, you press the “Build Snapshot” button in the bottom right corner of the screen. This will Build your AutoTest into a Snapshot (a history of your snapshots are available via the Snapshots tab).

After pressing "Build Snapshot", you can:

• Test the configuration by seeing the results in seconds.

• If you are ready to publish your AutoTest to your students press the big green Publish button.

• If you make any changes, you build again and if you are satisfied, you can republish them to your students.

• If you want to unpublish your snapshot, you can simply go to it in the green bar and press the red “Unpublish” button.

Step 1: Setup

CodeGrade AutoTest V2 runs on Ubuntu (20.04 LTS) machines which you can configure in any way that you want. Common software is pre-installed, but you can manually install software.

In the setup section of your AutoTest, you can install software or packages and upload any files you might need for testing. The setup section will build an image and is only run once for all submissions.

You can upload files using the "Upload Files" block. This is where you would upload all the fixtures needed to run your tests. These files will be placed in the $UPLOADED_FILES directory on the Virtual Server.

You can install software and packages (or configure the build image in any other way) using the "Script" block. You may use a command like python3 -m pip install semgrep if you are planning to use code structure tests using semgrep in your tests.

Installing PHP

In the setup you can install php8.2 by running the following bash script within a script block:# Write your bash script here.

sudo apt update && sudo apt upgrade
sudo apt install software-properties-common ca-certificates lsb-release apt-transport-https 
LC_ALL=C.UTF-8 sudo add-apt-repository ppa:ondrej/php 
sudo apt update 
sudo apt install php8.2

Setup for a simple PHP assignment: PHP is installed and a fixture is uploaded.

Step 2: Tests

Now that you have created the setup, it's time to create the actual tests. This is done on the Tests tab. Select one of the many test-blocks to configure a AutoTest V2 procedure in a "scratch"-like format. Some tests can be nested and you can chose to connect tests to rubric categories with a certain weight, you can also hide aspects of tests and enable internet access for specific tests.

Set up an IO Test

IO Tests are great for console based programs and allow you to give an input to it and specify an expected output. The following will guide you to set up an IO Test:

Basic IO Test to autograde a PHP assignment with user input (connected to a rubric).

1. Drag the "IO Test" block to your Test Procedure. In the code section, write the command to execute, for PHP this could be something like php fibonacci.php.

2. Drag one or more "Full Match" or "Substring Match" block(s) inside your "IO Test" block. Specify an Input (given via stdin / standard input) and an Expected Output.

3. Give clear names to the numerous blocks you have created to make clear to the students what is being tested.

4. Optionally: drag in a "Connect Rubric" block and drag your "IO Test" block in this, to connect it to a rubric category and use it to grade your students.

Set up a Code Structure test

CodeGrade integrates a tool called Semgrep to make it easy to perform more complex code analysis by allowing you to write rules in a human readable format. You can provide generic or language specific patterns, which are then found in the code. With its pattern syntax, you can find:

• Equivalences: Matching code that means the same thing even though it looks different.

• Wildcards / ellipsis (...): Matching any statement, expression or variable.

• Metavariables ($X): Matching unknown expressions that you do not yet know what they will exactly look like, but want to be the same variable in multiple parts of your pattern.

Writing the tests

Semgrep can be installed in the Setup step using pip, use: pip3 install semgrep. The easiest way to use Semgrep in AutoTest V2 is via our structure.py script (this will be built-in in a later version, but at the moment needs to be uploaded during the setup phase). With this script, you will write your Semgrep patterns directly in the Input field in an IO Test. Try out Semgrep patterns using their online editor here:

Semgrep

For instance, this is a pattern to detect a for-loop in the student code:

pattern: for ( ... ) { ... }

Creating the test in CodeGrade

2KB

structure.py

1. Under the Setup tab, upload the structure.py file you can download above. Also, in a "Script" block, install Semgrep via pip3 install semgrep.

2. Continue in the Tests tab: first drag the "IO Test" block to your Test Procedure. Execute the script in the code field, follow: python3 $UPLOADED_FILES/structure.py <STUDENTFILE>. For a fibonacci assignment, this could be: python3 $UPLOADED_FILES/structure.py fibonacci.php.

3. Create and drag one or more "Simple Test" block(s) inside your "IO Test" block. Each block is one Semgrep structure to check. As Input write the Semgrep pattern (including pattern: or similar like pattern-either:). If you want to check if the student uses an echo statement, use: pattern: echo $VAR;.

4. As Expected Output write "Found!" if the student code should match or "Not found!" if the student code should not contain the pattern (e.g. students are not allowed to use echo).

5. Optionally: Use a "Connect Rubric" block to connect your structure check to a rubric category.

6. Optionally: Use a "Hide" block to hide the "config" (i.e. input / pattern) of your tests so that students cannot see the pattern you are checking for.

A Semgrep structure check in an IO Test in AutoTest V2 (with optional Hide block to hide the pattern).