Update README.md

Author: dpellow

README.md

@@ -6,6 +6,7 @@ SCAPP assembles plasmids from metagenomic assembly graphs.
   * [With Conda](#with-conda)
   * [From sources](#from-sources)
       - [Configuring paths to required executables](#configuring-paths-to-required-executables)
+      - [Testing your SCAPP installation](#testing-your-scapp-installation)
 - [Basic Usage](#basic-usage)
 - [Main output files](#main-output-files)
 - [Advanced usage](#advanced-usage)
@@ -68,6 +69,11 @@ The BWA, samtools, and BLAST+ executables must be available to SCAPP. They can e
 
 For example, if the BWA executable is in `/usr/bin/bwa/` then the line `"BWA_PATH" : "/usr/bin/bwa",` should be completed in the `config.json` file if that location is not in your `PATH`.
 
+##### Testing your SCAPP installation
+Once you have completed the above you can run `./run_test.sh` from the outermost SCAPP directory to test your installation.
+
+(If the test fails please ensure you have set up the environment, installed, and configured SCAPP as described. Open an issue on this GitHub page with any problems you run into.)
+
 ## Basic Usage
 To run the SCAPP pipeline: 
 ```