test(gpio): assert that the GPIO types are zero cost memory-wise (ari…

…el-os#482)

.github/workflows/main.yml

@@ -116,7 +116,7 @@ jobs:
       # TODO: we'll eventually want to enable relevant features
       - name: Run crate tests
         run: |
-            cargo test --no-default-features --features i2c,no-boards -p riot-rs -p riot-rs-embassy -p riot-rs-embassy-common -p riot-rs-runqueue -p riot-rs-threads -p riot-rs-macros
+            cargo test --no-default-features --features external-interrupts,i2c,no-boards -p riot-rs -p riot-rs-embassy -p riot-rs-embassy-common -p riot-rs-runqueue -p riot-rs-threads -p riot-rs-macros
             cargo test -p rbi -p ringbuffer -p coapcore
 
       # We need to set `RUSTDOCFLAGS` as well in the following jobs, because it

src/riot-rs-embassy/src/gpio.rs

@@ -477,3 +477,16 @@ macro_rules! impl_embedded_hal_output_traits {
 }
 
 impl_embedded_hal_output_traits!(Output, ArchOutput);
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn check_gpio_type_sizes() {
+        // Assert that the GPIO types are zero cost memory-wise.
+        assert_eq!(size_of::<Input>(), size_of::<()>());
+        assert_eq!(size_of::<IntEnabledInput>(), size_of::<()>());
+        assert_eq!(size_of::<Output>(), size_of::<()>());
+    }
+}