This post dives into Plang, an intent-based programming language that interprets natural language. For more, visit plang.is or get started here.

In Plang, you can bind events to goals and steps, which opens up a fascinating possibility for automatic testing. Let's walk through an example, starting with something simple: adding two numbers.

A Simple Example: Adding Two Numbers

Here’s a basic code snippet in Plang:

AddTwoNumbers
- %num1% + %num2%, write to %sum%
- write out %sum%

To build automatic unit tests, let's first think about the usual process of testing logic manually. Without automation, you’d run something like this:

plang num1=1 num2=2

This would output:

3

Automating the Process

Because Plang lets us bind events to steps, we can automate this process. For example:

Events
- before each step, call PrepareUnitTest
- after each step, call MakeUnitTest

Here’s how it works:

• The PrepareUnitTest goal stores the variables in the current step.
• The MakeUnitTest goal captures the output, like the value of %sum%.

Once that’s in place, we can even ask the LLM to generate unit tests for us. This results in a JSON file with the relevant test values.

A Developer’s Interface

At this point, a developer would likely need a simple interface—a GUI—to tweak those values, add new tests, or remove unnecessary ones. Each module would define its own rules for unit testing, especially for handling I/O operations like HTTP requests, which would require special considerations.

With this setup, automatic testing becomes a streamlined part of the development process, enhancing efficiency and reliability in Plang projects.

In Theory

This post is titled In Theory because, at this point, automatic unit testing with Plang is just that—a theory. It hasn’t been implemented or tested yet, but there’s no reason it couldn’t be. The concept is sound; it’s just a matter of engineering time.

More Information

Interested in learning more about Plang? Here are some useful resources to get started:

• Basic Concepts and Lessons
• Todo Example to build a simple web service
• Explore the GitHub repo for source code
• Join our Discord Community for discussions and support
• Or chat with the Plang Assistant to get help with code generation