Add Rust tests and less code

src/geom.rs

@@ -1,29 +1,19 @@
 use std::os::raw::*;
 
 #[repr(C)]
+#[derive(Default)]
 pub struct Position {
     x: c_int,
     y: c_int,
 }
 
 #[repr(C)]
+#[derive(Default)]
 pub struct Sizes {
     width: c_int,
     height: c_int,
 }
 
-impl Default for Position {
-    fn default() -> Self {
-        Self::new(0, 0)
-    }
-}
-
-impl Default for Sizes {
-    fn default() -> Self {
-        Self::new(0, 0)
-    }
-}
-
 impl Position {
     pub fn new(x: c_int, y: c_int) -> Self {
         Self { x, y }
@@ -51,3 +41,20 @@ impl Sizes {
         self.height
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn position_default() {
+        assert_eq!(Position::default().x(), 0);
+        assert_eq!(Position::default().y(), 0);
+    }
+
+    #[test]
+    fn sizes_default() {
+        assert_eq!(Sizes::default().width(), 0);
+        assert_eq!(Sizes::default().height(), 0);
+    }
+}