it: use single-pixel buffer instead of shm

src/it/test_ifs/test_viewport.rs

@@ -0,0 +1,52 @@
+use {
+    crate::{
+        fixed::Fixed,
+        it::{test_error::TestError, test_object::TestObject, test_transport::TestTransport},
+        wire::{wp_viewport::*, WpViewportId},
+    },
+    std::rc::Rc,
+};
+
+pub struct TestViewport {
+    pub id: WpViewportId,
+    pub tran: Rc<TestTransport>,
+}
+
+impl TestViewport {
+    pub fn destroy(&self) -> Result<(), TestError> {
+        self.tran.send(Destroy { self_id: self.id })?;
+        Ok(())
+    }
+
+    pub fn set_source(&self, x: i32, y: i32, width: i32, height: i32) -> Result<(), TestError> {
+        self.tran.send(SetSource {
+            self_id: self.id,
+            x: Fixed::from_int(x),
+            y: Fixed::from_int(y),
+            width: Fixed::from_int(width),
+            height: Fixed::from_int(height),
+        })?;
+        Ok(())
+    }
+
+    pub fn set_destination(&self, width: i32, height: i32) -> Result<(), TestError> {
+        self.tran.send(SetDestination {
+            self_id: self.id,
+            width: width.max(1),
+            height: height.max(1),
+        })?;
+        Ok(())
+    }
+}
+
+impl Drop for TestViewport {
+    fn drop(&mut self) {
+        let _ = self.destroy();
+    }
+}
+
+test_object! {
+    TestViewport, WpViewport;
+}
+
+impl TestObject for TestViewport {}