Update README.md with Google Testframework configuration

Add a description in how to install the Google testframe manually

README.md

@@ -12,9 +12,18 @@ License|Linux & macOS Build
 This is a Cmake project and can be run in any C++ IDE (Integrated Development Environment) that is on the market and supports CMake. You have to define a certain set of parameters dependent on your system and what you wish to run in general. The following will help you with the initial setup and links to the frameworks that can be linked in addition.
 
 <h3>Required Preinstallations</h3>
+
 Qt (for now)
 clang or gcc
 
+If the tests are enabled `"EGOA_TEST_FRAMEWORK": "OfflineGoogleTestFramework"` the `"EGOA_TEST_FRAMEWORK_LOCATION"`, e.g., `"EGOA_TEST_FRAMEWORK_LOCATION": "external/googletest"`, needs a valid path to the test framework. If you prefer to manualy set the path, the <a href="https://github.com/google/googletest/tree/main">google test framework</a> can be cloned from https://github.com/google/googletest/tree/main, which is the easiest way to have a up-to-date version of the repository. Using the above example configuration run:
+
+```
+> cd egoa
+> cd external
+> git clone https://github.com/google/googletest.git
+```
+
 <h3>CMake Parameter Overrides</h3>
 
 The repository provides an intial set of parameters in the sublimetext project file that can be found under `egoa.sublime-project`.