Expect Assertion

The Expect assertion evaluates a PHP expression that must be truthy.

Syntax

```php
$result = array_sum([1, 2, 3, 4, 5]);
```
<!-- doctest-expect: $result === 15 -->

How It Works

1. The code block executes
2. After the code runs, the expression is evaluated with (bool)(expression)
3. If the expression evaluates to true, the assertion passes
4. If it evaluates to false, the assertion fails with the expression shown in the error

Expression Scope

The expression has access to all variables defined in the code block:

$items = [1, 2, 3];
$count = count($items);
$sum = array_sum($items);

Multiple Expects

You can have multiple Expect assertions on the same block:

$name = 'DocTest';
$version = 1;

When to Use

• When you need to verify a computed value without printing it
• When the assertion involves a comparison or function call
• When documenting APIs where return values matter more than printed output

Tips

• The expression must be a valid PHP expression
• Use strict comparisons (===) when possible
• You can call functions in the expression: <!-- doctest-expect: is_array($result) -->