Update README.md

Author: rybakit

README.md

@@ -2,7 +2,19 @@
 
 ![Continuous Integration](https://github.com/tarantool-php/phpunit-extras/workflows/Continuous%20Integration/badge.svg)
 
-A collection of helpers for [PHPUnit](https://phpunit.de/) to ease testing [Tarantool](https://www.tarantool.io/en/developers/) libraries. 
+A collection of helpers for [PHPUnit](https://phpunit.de/) to ease testing [Tarantool](https://www.tarantool.io/en/developers/) libraries.
+
+
+## Table of contents
+
+ * [Installation](#installation)
+ * [Annotations](#annotations)
+   * [Processors](#processors)
+   * [Requirements](#requirements)
+ * [Expectations](#expectations)
+ * [Mocking](#mocking)
+ * [Testing](#testing)
+ * [License](#license)
 
 
 ## Installation
@@ -85,6 +97,116 @@ public function testPrepareCreatesPreparedStatement() : void
 
 ## Expectations
 
+*RequestExpectations*
+
+```php
+public function testGetSpaceIsCached() : void
+{
+    $this->client->flushSpaces();
+
+    $this->expectSelectRequestToBeCalledOnce();
+    $this->client->getSpace('test_space')->delete(42);
+    $this->client->getSpace('test_space')->delete(42);
+}
+```
+
+
+## Mocking
+
+This library provides several helper classes to mock the [Tarantool Client](https://github.com/tarantool-php/client)
+without having to send real requests to the Tarantool server. For convenient creation of mocks in your tests, 
+add a `ClientMocking` trait to your test case:
+
+```php
+use Tarantool\PhpUnit\Client\ClientMocking;
+
+final class MyTest extends TestCase
+{
+    use ClientMocking;
+
+    // ...
+}
+```
+
+> *Note*
+>
+> If your test cases extend the `Tarantool\PhpUnit\TestCase` class, this step is not needed
+> because the trait is already included in that class.
+
+The most basic version of the mock object can be created as follows:
+
+```php
+public function testFoo() : void
+{
+    $mockClient = $this->createMockClient();
+
+    // ...
+}
+```
+
+To simulate specific scenarios, such as establishing a connection to a server
+or returning specific responses in a specific order from a server, use the facilities
+of the `MockClientBuilder` class. For example, to simulate the ping request/response:
+
+```php
+use Tarantool\Client\Request\PingRequest;
+use Tarantool\PhpUnit\Client\DummyFactory;
+
+public function testFoo() : void
+{
+    $mockClient = $this->getMockClientBuilder()
+        ->shouldHandle(
+            new PingRequest(),
+            DummyFactory::createEmptyResponse()
+        )->build();
+
+    // ...
+}
+```
+
+Another example, sending two `EVALUATE` requests and returning a different response for each:
+
+```php
+use Tarantool\Client\RequestTypes;
+use Tarantool\PhpUnit\Client\DummyFactory;
+
+public function testFoo() : void
+{
+    $mockClient = $this->getMockClientBuilder()
+        ->shouldHandle(
+            RequestTypes::EVALUATE,
+            DummyFactory::createResponseFromData([2]),
+            DummyFactory::createResponseFromData([3])
+        )->build();
+
+    // ...
+}
+```
+
+Besides, the builder allows setting custom `Connection` and `Packer` instances:
+
+```php
+$mockClient = $this->getMockClientBuilder()
+    ->willUseConnection($myConnection)
+    ->willUsePacker($myPacker)
+    ->build();
+```
+
+## Testing
+
+Before running tests, the development dependencies must be installed:
+
+```bash
+composer install
+```
+
+Then, to run all the tests:
+
+```bash
+vendor/bin/phpunit
+vendor/bin/phpunit -c phpunit-extension.xml
+```
+
 
 ## License