# Asserts
Special module for using asserts in your tests.
## Actions
### assertArrayHasKey
* `param` $key
* `param` $actual
* `param` $description
### assertArrayNotHasKey
* `param` $key
* `param` $actual
* `param` $description
### assertArraySubset
Checks that array contains subset.
* `param array` $subset
* `param array` $array
* `param bool` $strict
* `param string` $message
### assertContains
Checks that haystack contains needle
* `param` $needle
* `param` $haystack
* `param string` $message
### assertCount
* `param` $expectedCount
* `param` $actual
* `param` $description
### assertEmpty
Checks that variable is empty.
* `param` $actual
* `param string` $message
### assertEquals
Checks that two variables are equal. If you're comparing floating-point values,
you can specify the optional "delta" parameter which dictates how great of a precision
error are you willing to tolerate in order to consider the two values equal.
Regular example:
```php
<?php
$I->assertEquals(5, $element->getChildrenCount());
```
Floating-point example:
```php
<?php
$I->assertEquals(0.3, $calculator->add(0.1, 0.2), 'Calculator should add the two numbers correctly.', 0.01);
```
* `param` $expected
* `param` $actual
* `param string` $message
* `param float` $delta
### assertFalse
Checks that condition is negative.
* `param` $condition
* `param string` $message
### assertFileExists
Checks if file exists
* `param string` $filename
* `param string` $message
### assertFileNotExists
Checks if file doesn't exist
* `param string` $filename
* `param string` $message
### assertGreaterOrEquals
* `param` $expected
* `param` $actual
* `param` $description
### assertGreaterThan
Checks that actual is greater than expected
* `param` $expected
* `param` $actual
* `param string` $message
### assertGreaterThanOrEqual
Checks that actual is greater or equal than expected
* `param` $expected
* `param` $actual
* `param string` $message
### assertInstanceOf
* `param` $class
* `param` $actual
* `param` $description
### assertInternalType
* `param` $type
* `param` $actual
* `param` $description
### assertIsEmpty
* `param` $actual
* `param` $description
### assertLessOrEquals
* `param` $expected
* `param` $actual
* `param` $description
### assertLessThan
Checks that actual is less than expected
* `param` $expected
* `param` $actual
* `param string` $message
### assertLessThanOrEqual
Checks that actual is less or equal than expected
* `param` $expected
* `param` $actual
* `param string` $message
### assertNotContains
Checks that haystack doesn't contain needle.
* `param` $needle
* `param` $haystack
* `param string` $message
### assertNotEmpty
Checks that variable is not empty.
* `param` $actual
* `param string` $message
### assertNotEquals
Checks that two variables are not equal. If you're comparing floating-point values,
you can specify the optional "delta" parameter which dictates how great of a precision
error are you willing to tolerate in order to consider the two values not equal.
Regular example:
```php
<?php
$I->assertNotEquals(0, $element->getChildrenCount());
```
Floating-point example:
```php
<?php
$I->assertNotEquals(0.4, $calculator->add(0.1, 0.2), 'Calculator should add the two numbers correctly.', 0.01);
```
* `param` $expected
* `param` $actual
* `param string` $message
* `param float` $delta
### assertNotFalse
Checks that the condition is NOT false (everything but false)
* `param` $condition
* `param string` $message
### assertNotInstanceOf
* `param` $class
* `param` $actual
* `param` $description
### assertNotNull
Checks that variable is not NULL
* `param` $actual
* `param string` $message
### assertNotRegExp
Checks that string not match with pattern
* `param string` $pattern
* `param string` $string
* `param string` $message
### assertNotSame
Checks that two variables are not same
* `param` $expected
* `param` $actual
* `param string` $message
### assertNotTrue
Checks that the condition is NOT true (everything but true)
* `param` $condition
* `param string` $message
### assertNull
Checks that variable is NULL
* `param` $actual
* `param string` $message
### assertRegExp
Checks that string match with pattern
* `param string` $pattern
* `param string` $string
* `param string` $message
### assertSame
Checks that two variables are same
* `param` $expected
* `param` $actual
* `param string` $message
### assertStringStartsNotWith
Checks that a string doesn't start with the given prefix.
* `param string` $prefix
* `param string` $string
* `param string` $message
### assertStringStartsWith
Checks that a string starts with the given prefix.
* `param string` $prefix
* `param string` $string
* `param string` $message
### assertTrue
Checks that condition is positive.
* `param` $condition
* `param string` $message
### expectException
Handles and checks exception called inside callback function.
Either exception class name or exception instance should be provided.
```php
<?php
$I->expectException(MyException::class, function() {
$this->doSomethingBad();
});
$I->expectException(new MyException(), function() {
$this->doSomethingBad();
});
```
If you want to check message or exception code, you can pass them with exception instance:
```php
<?php
// will check that exception MyException is thrown with "Don't do bad things" message
$I->expectException(new MyException("Don't do bad things"), function() {
$this->doSomethingBad();
});
```
* `param` $exception string or \Exception
* `param` $callback
@deprecated Use expectThrowable instead
### expectThrowable
Handles and checks throwables (Exceptions/Errors) called inside the callback function.
Either throwable class name or throwable instance should be provided.
```php
<?php
$I->expectThrowable(MyThrowable::class, function() {
$this->doSomethingBad();
});
$I->expectThrowable(new MyException(), function() {
$this->doSomethingBad();
});
```
If you want to check message or throwable code, you can pass them with throwable instance:
```php
<?php
// will check that throwable MyError is thrown with "Don't do bad things" message
$I->expectThrowable(new MyError("Don't do bad things"), function() {
$this->doSomethingBad();
});
```
* `param` $throwable string or \Throwable
* `param` $callback
### fail
Fails the test with message.
* `param` $message
<p> </p><div class="alert alert-warning">Module reference is taken from the source code. <a href="https://github.com/Codeception/Codeception/tree/2.5/src/Codeception/Module/Asserts.php">Help us to improve documentation. Edit module reference</a></div>