readme: describe how to run tests

Describe how to run connector tests (with submodules) and
test requirements.

Closes #106

Author: DifferentialOrange

README.md

@@ -27,6 +27,7 @@ faster than other packages according to public benchmarks.
 * [Custom (un)packing and typed selects and function calls](#custom-unpacking-and-typed-selects-and-function-calls)
 * [Options](#options)
 * [Working with queue](#working-with-queue)
+* [Tests](#tests)
 * [Alternative connectors](#alternative-connectors)
 
 ## Installation
@@ -673,6 +674,34 @@ Additional options (configurable via `ConnectWithOpts`):
 * `ClusterDiscoveryTime` - time interval to ask server for updated address list (works on with `NodesGetFunctionName` set)
 * `NodesGetFunctionName` - server lua function name to call for getting address list
 
+## Tests
+
+You need to [install Tarantool](https://www.tarantool.io/en/download/) to run tests.
+See (Installation)[(#installation)] section for other requirements and version restrictions.
+
+To run tests, call
+```bash
+go clean -testcache && go test -v
+```
+Tests configure all required environment (`tarantool` processes to connect or `.rocks` installed) before run.
+
+To run subpackage tests, go to a subpackage folder and run the same command.
+```bash
+cd multi
+go clean -testcache && go test -v
+```
+
+```bash
+cd queue
+go clean -testcache && go test -v
+```
+
+UUID tests require [Tarantool 2.4.1 or newer](https://github.com/tarantool/tarantool/commit/d68fc29246714eee505bc9bbcd84a02de17972c5).
+```bash
+cd UUID
+go clean -testcache && go test -v
+```
+
 ## Alternative connectors
 
 - https://github.com/viciious/go-tarantool