--- a/rust/Cargo.toml	Thu Mar 23 00:20:22 2017 +0800
+++ b/rust/Cargo.toml	Sat Apr 15 23:39:23 2017 +0800
@@ -24,4 +24,5 @@
 base64 = "0.4"
 
 # linux only
+[target.linux.dependencies]
 sysfs_gpio = "0.5"

--- a/rust/src/fridge.rs	Thu Mar 23 00:20:22 2017 +0800
+++ b/rust/src/fridge.rs	Sat Apr 15 23:39:23 2017 +0800
@@ -1,5 +1,6 @@
 extern crate futures;
 extern crate tokio_core;
+#[cfg(linux)]
 extern crate sysfs_gpio;
 
 use std;
@@ -11,6 +12,8 @@
 use futures::{Future,future,Sink,Stream};
 use tokio_core::reactor::{Timeout,Handle};
 use futures::sync::{mpsc};
+
+#[cfg(target_os = "linux")]
 use sysfs_gpio::{Direction, Pin};
 
 use config::Config;
@@ -34,7 +37,7 @@
     last_off_time: Instant,
     wort_valid_time: Instant,
     integrator: StepIntegrator,
-    gpio: Pin,
+    control: FridgeControl,
 
     // Timeouts to wake ourselves up again
     handle: Handle,
@@ -59,10 +62,18 @@
     }
 }
 
+enum FridgeControl {
+#[cfg(target_os = "linux")]
+    Gpio(Pin),
+    Fake,
+}
+
+struct TestControl {}
+
 impl Drop for Fridge {
     fn drop(&mut self) {
         // safety fridge off 
-        self.gpio.set_state(0);
+        self.turn(false);
     }
 }
 
@@ -77,8 +88,8 @@
             temp_fridge: None,
             last_off_time: Instant::now(),
             wort_valid_time: Instant::now() - Duration::new(config.FRIDGE_WORT_INVALID_TIME, 100),
-            integrator: StepIntegrator::new(p.overshoot_delay),
-            gpio: Pin::new(config.FRIDGE_GPIO_PIN),
+            integrator: StepIntegrator::new(Duration::new(p.overshoot_delay, 0)),
+            control: Self::make_control(config),
 
             handle: handle.clone(),
             timeout_s: s,
@@ -90,15 +101,27 @@
             f.last_off_time -= Duration::new(config.FRIDGE_DELAY, 1);
         }
 
-        // XXX better error handling?
-        f.gpio.export().expect("Exporting fridge gpio failed");
-        f.gpio.set_direction(Direction::Low).expect("Fridge gpio direction failed");
-
         f.tick();
 
         f
     }
 
+#[cfg(target_os = "linux")]
+    fn make_control(config: &Config) -> FridgeControl {
+        let mut pin = Pin(config.FRIDGE_GPIO_PIN);
+        // XXX better error handling?
+        pin.export().expect("Exporting fridge gpio failed");
+        pin.set_direction(Direction::Low).expect("Fridge gpio direction failed");
+        FridgeControl::Gpio(pin)
+    }
+
+#[cfg(not(target_os = "linux"))]
+    fn make_control(config: &Config) -> FridgeControl {
+            FridgeControl::Fake
+    }
+
+
+
     fn next_wakeup(&self) -> Duration {
         let millis = 400;
         let dur = Duration::from_millis(millis);
@@ -123,18 +146,22 @@
     }
 
     fn turn_off(&mut self) {
-        log!("Turning fridge off");
+        info!("Turning fridge off");
         self.turn(false);
     }
 
     fn turn_on(&mut self) {
-        log!("Turning fridge on");
+        info!("Turning fridge on");
         self.turn(true);
     }
 
     fn turn(&mut self, on: bool) {
+        match self.control {
+#[cfg(target_os = "linux")]
+            Gpio(pin) => pin.set_value(on as u8),
+            FridgeControl::Fake => debug!("fridge turns {}", if on {"on"} else {"off"}),
+        }
         self.on = on;
-        self.gpio.set_value(on as u8)
     }
 
     /// Turns the fridge off and on
@@ -145,18 +172,18 @@
         let off_time = Instant::now() - self.last_off_time;
 
         // Or elsewhere?
-        self.integrator.set_limit(self.params.overshoot_delay);
+        self.integrator.set_limit(Duration::new(self.params.overshoot_delay, 0));
 
         // Safety to avoid bad things happening to the fridge motor (?)
         // When it turns off don't start up again for at least FRIDGE_DELAY
-        if !self.on && off_time < self.config.FRIDGE_DELAY {
-            log!("fridge skipping, too early");
+        if !self.on && off_time < Duration::new(self.config.FRIDGE_DELAY, 0) {
+            info!("fridge skipping, too early");
             return;
         }
 
         if self.params.disabled {
             if self.on {
-                log!("Disabled, turning fridge off");
+                info!("Disabled, turning fridge off");
                 self.turn_off();
             }
             return;
@@ -166,7 +193,7 @@
         if self.temp_wort.is_none() {
             let invalid_time = Instant::now() - self.wort_valid_time;
             warn!("Invalid wort sensor for {:?} secs", invalid_time);
-            if invalid_time < self.config.FRIDGE_WORT_INVALID_TIME {
+            if invalid_time < Duration::new(self.config.FRIDGE_WORT_INVALID_TIME, 0) {
                 warn!("Has only been invalid for {:?}, waiting", invalid_time);
                 return;
             }
@@ -179,27 +206,28 @@
         if self.on {
             debug!("fridge is on");
             let on_time = self.integrator.integrate().as_secs() as f32;
-            let on_ratio = on_time / params.overshoot_delay as f32;
+            let on_ratio = on_time / self.params.overshoot_delay as f32;
 
-            overshoot = params.overshoot_factor as f32 * on_ratio;
-            debug!("on_time {}, overshoot {}", on_percent, overshoot);
+            let overshoot = self.params.overshoot_factor as f32 * on_ratio;
+            debug!("on_percent {}, overshoot {}", on_ratio * 100.0, overshoot);
 
             let mut turn_off = false;
-            if let Some(t) = self.temp_wort && !params.nowort {
+            if self.temp_wort.is_some() && !self.params.nowort {
+                let t = self.temp_wort.unwrap();
                 // use the wort temperature
-                if t - overshoot < params.fridge_setpoint {
-                    log!("wort has cooled enough, {temp}º (overshoot {overshoot}º = {factor} × {percent}%)",
+                if t - overshoot < self.params.fridge_setpoint {
+                    info!("wort has cooled enough, {temp}º (overshoot {overshoot}º = {factor} × {percent}%)",
                          temp = t, overshoot = overshoot,
-                         factor = params.overshoot_factor,
-                         percent = on_ratio*100);
+                         factor = self.params.overshoot_factor,
+                         percent = on_ratio*100.0);
                     turn_off = true;
                 }
-            } else let if Some(t) = self.temp_fridge {
+            } else if let Some(t) = self.temp_fridge {
                 // use the fridge temperature
                 if t < fridge_min {
                     warn!("fridge off fallback, fridge {}, min {}", t, fridge_min);
                     if self.temp_wort.is_none() {
-                        W("wort has been invalid for {:?}", Instant::now() - self.wort_valid_time);
+                        warn!("wort has been invalid for {:?}", Instant::now() - self.wort_valid_time);
                     }
                     turn_off = true;
                 }
@@ -211,17 +239,18 @@
             debug!("fridge is off. fridge {:?} max {:?}. wort {:?} max {:?}",
                 self.temp_fridge, fridge_max, self.temp_wort, wort_max);
             let mut turn_on = false;
-            if let Some(t) = self.temp_wort && !params.nowort {
+            if self.temp_wort.is_some() && !self.params.nowort {
                 // use the wort temperature
+                let t = self.temp_wort.unwrap();
                 if t >= wort_max {
-                    log!("Wort is too hot {}°, max {}°", t, wort_max);
+                    info!("Wort is too hot {}°, max {}°", t, wort_max);
                     turn_on = true;
                 }
             } 
 
             if let Some(t) = self.temp_fridge {
                 if t >= fridge_max {
-                    warn!("fridge too hot fallback, fridge {}°, max {}°", t, fridge_max)
+                    warn!("fridge too hot fallback, fridge {}°, max {}°", t, fridge_max);
                     turn_on = true;
                 }
             }
@@ -237,7 +266,7 @@
     fn tick(&mut self) {
         debug!("tick");
 
-        self.compare_temperatures()
+        self.compare_temperatures();
         self.send_next_timeout();
     }
 

--- a/rust/src/params.rs	Thu Mar 23 00:20:22 2017 +0800
+++ b/rust/src/params.rs	Sat Apr 15 23:39:23 2017 +0800
@@ -27,7 +27,7 @@
 pub struct Params {
     pub fridge_setpoint: f32,
     pub fridge_difference: f32,
-    pub overshoot_delay: u32,
+    pub overshoot_delay: u64,
     pub overshoot_factor: f32,
     pub disabled: bool,
     pub nowort: bool,

--- a/rust/src/types.rs	Thu Mar 23 00:20:22 2017 +0800
+++ b/rust/src/types.rs	Sat Apr 15 23:39:23 2017 +0800
@@ -238,7 +238,7 @@
         self.trim();
     }
 
-    fn integrate(&self) -> Duration {
+    pub fn integrate(&self) -> Duration {
         let durs = self.on_periods.iter().map(|p| {
             let end = p.end.unwrap_or_else(|| Instant::now());
             end - p.start