+++ title = "15. Unit Testing Framework" weight = 15 +++

15. Unit Testing Framework {#15-unit-testing-framework}

Zen C features a built-in testing framework that allows you to write unit tests directly in your source files using the test keyword.

Syntax

A test block contains a descriptive name and a body of code to execute. Tests do not require a main function to run.

test "unittest1" {
    "This is an unittest";

    let a = 3;
    assert(a > 0, "a should be a positive integer");

    "unittest1 passed.";
}

Running Tests

To run all tests in a file, use the run command. The compiler will automatically detect and execute all top-level test blocks.

zc run my_file.zc

Assertions

Use the built-in assert(condition, message) function to verify expectations. If the condition is false, the test will fail and print the provided message.

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Tooling

Zen C provides a built-in Language Server and REPL to enhance the development experience. It is also debuggable with LLDB.

Language Server (LSP)

The Zen C Language Server (LSP) supports standard LSP features for editor integration, providing:

• Go to Definition
• Find References
• Hover Information (including custom DSL plugins)
• Completion (Function/Struct names, Dot-completion for methods/fields)
• Document Symbols (Outline)
• Signature Help
• Diagnostics (Syntax/Semantic errors)

To start the language server (typically configured in your editor's LSP settings):

zc lsp

It communicates via standard I/O (JSON-RPC 2.0).

REPL

The Read-Eval-Print Loop allows you to experiment with Zen C code interactively.

zc repl

Features

• Interactive Coding: Type expressions or statements for immediate evaluation.
• Persistent History: Commands are saved to ~/.zprep_history.
• Startup Script: Auto-loads commands from ~/.zprep_init.zc.

Commands

Command	Description
:help	Show available commands.
:reset	Clear current session history (variables/functions).
:vars	Show active variables.
:funcs	Show user-defined functions.
:structs	Show user-defined structs.
:imports	Show active imports.
:history	Show session input history.
:type <expr>	Show the type of an expression.
:c <stmt>	Show the generated C code for a statement.
:time <expr>	Benchmark an expression (runs 1000 iterations).
:edit [n]	Edit command n (default: last) in $EDITOR.
:save <file>	Save the current session to a .zc file.
:load <file>	Load and execute a .zc file into the session.
:watch <expr>	Watch an expression (re-evaluated after every entry).
:unwatch <n>	Remove a watch.
:undo	Remove the last command from the session.
:delete <n>	Remove command at index n.
:clear	Clear the screen.
:quit	Exit the REPL.
! <cmd>	Run a shell command (e.g. !ls).

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Language Server Protocol (LSP)

Zen C includes a built-in Language Server for editor integration.

• Installation & Setup Guide
• Supported Editors: VS Code, Neovim, Vim (zenc.vim), Zed, and any LSP-capable editor.

Use zc lsp to start the server.

Debugging Zen C

Zen C programs can be debugged using standard C debuggers like LLDB or GDB.

Visual Studio Code

For the best experience in VS Code, install the official Zen C extension. For debugging, you can use the C/C++ (by Microsoft) or CodeLLDB extension.

Add these configurations to your .vscode directory to enable one-click debugging:

tasks.json (Build Task):

{
    "label": "Zen C: Build Debug",
    "type": "shell",
    "command": "zc",
    "args": [ "${file}", "-g", "-o", "${fileDirname}/app", "-O0" ],
    "group": { "kind": "build", "isDefault": true }
}

launch.json (Debugger):

{
    "name": "Zen C: Debug (LLDB)",
    "type": "lldb",
    "request": "launch",
    "program": "${fileDirname}/app",
    "preLaunchTask": "Zen C: Build Debug"
}