Update README.md for unit testing and submodules

1 files changed, 23 insertions, 0 deletions

diff --git a/README.md b/README.md
index 15a444b..76b77f7 100644
--- a/README.md
+++ b/README.md
@@ -2,6 +2,20 @@
 
 ## Getting Started
 
+### Submoule checkout
+
+This repo uses the [Unity](http://www.throwtheswitch.org/unity) unit testing
+library, as well as Bosch's BMP3 Sensor API, which are included as submodules.
+You must therefore do a recursive clone when cloning this repo initially, e.g.:
+
+	git clone --recursive https://git.nah.nz/altimeter/
+
+or later come along and check out the submodules if you didn't perform a
+recursive clone initially:
+
+	git submodule init && git submodule update
+
+
 ### Dependencies
 
 Bare minimum, you will need:
@@ -19,6 +33,15 @@ before flashing, you will need:
 
 * qemu-avr
 
+### Test
+
+In order to build and run the unit tests without building ELFs or HEXs:
+
+	$ make test
+
+Otherwise, unit tests are always run as the final part of the `make all` recipe
+below and will fail the build if they do not pass.
+
 ### Build
 
 	$ make all