Introduction

You are working on a utility that is responsible for secure text encoding. All encoders implement App\EncodingAlgorithm interface with a single encode($text) method that returns text or can throw an exception in case of failure.

Task definition

Your task is to implement encoders to pass all tests. As you can see encoders are empty and contain only @todo annotation. Behavior of each encoder is described in a docblock of encode method. Additional examples are prepared for you as tests.

To complete this task you should:

• implement App\OffsetEncodingAlgorithm
• implement App\SubstitutionEncodingAlgorithm
• implement App\CompositeEncodingAlgorithm

Hint

Think about how to prevent invalid inputs from being passed to the algorithms.

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