[EasyTest] Created InvalidDataMaker

[skrut]

Introducing a new util class helpful in functional tests of ApiResource validation.

Q	A
Bug fix?	no
New feature?	yes
BC breaks?	no
Deprecations?	no
Tests pass?	yes
Fixed tickets	...

InvalidDataMaker can be extended in an application to add new yield methods.

When custom validation messages are used in an application, a translation file path should be added either by overriding the InvalidDataMaker::$translations property or by calling the InvalidDataMaker::addTranslations() method from a setUp method.

All the yield methods generate an array with the following items: data (an array containing invalid data that can be passed to an API endpoint), message, and propertyPath (a translated message and a property path that can be used to assert the violation details in the error response).

Usage examples:

// The syntax used in most cases
yield from InvalidDataMaker::make('propertyName')->yieldBlankString();

// In case a path differs from a property name
yield from InvalidDataMaker::make('propertyName')
    ->propertyPath('some.specific.path.different.from.propertyName')
    ->yieldIntegerGreaterThanGiven(100);

// Useful when we apply a constraint with a custom validation message
yield from InvalidDataMaker::make('propertyName')
    ->message('Some custom message used instead of the one from the Symfony validator.')
    ->yieldBlankString();

// This is the only method for now, which generates a fixture for a custom constraint/validation
// (e.g. when a regex is used). So, we have to pass a custom message
yield from InvalidDataMaker::make('propertyName')
    ->message('Here we use a custom regex validator, so have to set a message.')
    ->yieldInvalidFloat();

// Generating an "object" with a nested property
yield from InvalidDataMaker::make('propertyName')
    ->wrapWith('nestedObjectName')
    ->message('Just to demonstrate chaining.')
    ->yieldBlankString();

// Generating an integer casted to a string. Can be useful for amounts stored as strings
yield from InvalidDataMaker::make('propertyName')
    ->asString()
    ->yieldIntegerGreaterThanGiven(1);

// Generating an array with a blank string inside
yield from InvalidDataMaker::make('propertyName')
    ->asArrayElement()
    ->yieldBlankString();