Add tests & README.md

.gitignore

@@ -2,3 +2,5 @@
 /.idea
 /.php_cs.cache
 /vendor/
+.phpunit.result.cache
+infection.log

README.md

@@ -0,0 +1,27 @@
+# Infection - Include Interceptor Stream Wrapper
+
+It's a [Stream Wrapper](https://www.php.net/manual/en/book.stream.php) that wraps a [`file://`](https://www.php.net/manual/en/wrappers.file.php) protocol and allows overriding content of any (auto) loaded file, including files autoloaded by Composer package manager.
+
+## How it works
+
+If you want to replace the content of the file whenever it's loaded (by executing `include '/path/to/file.php`, by calling `file_get_contents('/path/to/file.php')`, etc.), you need to register `IncludeInterceptor` _before_ loading original file:
+
+```php
+use Infection\StreamWrapper\IncludeInterceptor;
+
+IncludeInterceptor::intercept('/path/to/original_file.php', '/path/to/replacement_file.php');
+IncludeInterceptor::enable();
+```
+
+After enabling `IncludeInterceptor`, content of the `replacement_file.php` will be loaded instead of content of the `original_file.php`.  
+
+## Use cases
+
+* This Stream Wrapper is used to replace the original file with the Mutant in [Infection](http://infection.github.io) Mutation Testing Framework
+* The same approach is used in the [`dg/bypass-finals`](https://github.com/dg/bypass-finals/) package that allows to mock `final` classes, by overriding original content and removing `final` keyword in runtime
+
+## Infection - Mutation Testing Framework
+
+Please read documentation here: [infection.github.io](http://infection.github.io)
+
+Twitter: [@infection_php](http://twitter.com/infection_php)

composer.json

@@ -14,11 +14,19 @@
             "Infection\\StreamWrapper\\": "src/"
         }
     },
+    "autoload-dev": {
+        "psr-4": {
+            "Infection\\Tests\\StreamWrapper\\": "tests/"
+        }
+    },
     "config": {
         "platform": {
             "php": "7.2.9"
         },
         "sort-packages": true
     },
-    "require": {}
+    "require": {},
+    "require-dev": {
+        "phpunit/phpunit": "^8.5"
+    }
 }