Move the led_ring module to a local crate

The library will allow for the tests to be actually run.
If we try to run the tests through the main binary this fails
due to missing a eh_personality language item.

Cargo.toml

@@ -24,6 +24,10 @@ package = "stm32f4xx-hal"
 version = "0.3.0"
 features = ["rt", "stm32f407"]
 
+[lib]
+name = "stm32f4disc_demo"
+path = "src/lib.rs"
+
 [[bin]]
 name = "stm32f4disc-demo"
 test = false

src/lib.rs

@@ -0,0 +1,2 @@
+#![cfg_attr(not(test), no_std)]
+pub mod led_ring;

src/main.rs

@@ -8,10 +8,8 @@
 #![no_main]
 #![no_std]
 
-mod led_ring;
-
-use crate::led_ring::LedRing;
 use core::fmt::Write;
+
 use cortex_m_semihosting::hprintln;
 use hal::{
     block,
@@ -25,6 +23,7 @@ use heapless::{consts::U8, Vec};
 #[cfg(not(test))]
 use panic_semihosting as _;
 use rtfm::app;
+use stm32f4disc_demo::led_ring::LedRing;
 
 type Accelerometer = hal::spi::Spi<SPI1, (Spi1Sck, Spi1Miso, Spi1Mosi)>;
 type AccelerometerCs = hal::gpio::gpioe::PE3<Output<PushPull>>;