diff --git a/crates/domain/src/irq.rs b/crates/domain/src/irq.rs
deleted file mode 100644
index 4839573..0000000
--- a/crates/domain/src/irq.rs
+++ /dev/null
@@ -1,87 +0,0 @@
-use types::id::{IrqId, ThreadId};
-
-use crate::error::KernelError;
-
-const MAX_IRQS: usize = 256;
-
-pub struct IrqRoutingTable {
-    owners: [Option<ThreadId>; MAX_IRQS],
-}
-
-impl IrqRoutingTable {
-    pub fn new() -> Self {
-        Self {
-            owners: [None; MAX_IRQS],
-        }
-    }
-
-    pub fn register(&mut self, irq: IrqId, thread: ThreadId) -> Result<(), KernelError> {
-        let idx = irq.raw() as usize;
-        if self.owners[idx].is_some() {
-            return Err(KernelError::IrqAlreadyOwned(irq));
-        }
-        self.owners[idx] = Some(thread);
-        Ok(())
-    }
-
-    pub fn unregister(&mut self, irq: IrqId) {
-        self.owners[irq.raw() as usize] = None;
-    }
-
-    pub fn owner(&self, irq: IrqId) -> Option<ThreadId> {
-        self.owners[irq.raw() as usize]
-    }
-}
-
-#[cfg(test)]
-mod tests {
-    use super::*;
-
-    fn irq(id: u16) -> IrqId {
-        IrqId::from_raw(id)
-    }
-
-    fn thread(id: u16) -> ThreadId {
-        ThreadId::from_raw(id)
-    }
-
-    #[test]
-    fn new_table_has_no_owners() {
-        let table = IrqRoutingTable::new();
-        assert!(table.owner(irq(0)).is_none());
-        assert!(table.owner(irq(10)).is_none());
-    }
-
-    #[test]
-    fn register_and_lookup() {
-        let mut table = IrqRoutingTable::new();
-        table.register(irq(5), thread(1)).unwrap();
-        assert_eq!(table.owner(irq(5)), Some(thread(1)));
-    }
-
-    #[test]
-    fn register_already_owned_fails() {
-        let mut table = IrqRoutingTable::new();
-        table.register(irq(5), thread(1)).unwrap();
-        assert!(table.register(irq(5), thread(2)).is_err());
-    }
-
-    #[test]
-    fn unregister_then_reregister() {
-        let mut table = IrqRoutingTable::new();
-        table.register(irq(5), thread(1)).unwrap();
-        table.unregister(irq(5));
-        assert!(table.owner(irq(5)).is_none());
-        table.register(irq(5), thread(2)).unwrap();
-        assert_eq!(table.owner(irq(5)), Some(thread(2)));
-    }
-
-    #[test]
-    fn different_irqs_independent() {
-        let mut table = IrqRoutingTable::new();
-        table.register(irq(0), thread(10)).unwrap();
-        table.register(irq(1), thread(20)).unwrap();
-        assert_eq!(table.owner(irq(0)), Some(thread(10)));
-        assert_eq!(table.owner(irq(1)), Some(thread(20)));
-    }
-}
diff --git a/crates/domain/src/irq/mod.rs b/crates/domain/src/irq/mod.rs
new file mode 100644
index 0000000..335d4c4
--- /dev/null
+++ b/crates/domain/src/irq/mod.rs
@@ -0,0 +1,38 @@
+use types::id::{IrqId, ThreadId};
+
+use crate::error::KernelError;
+
+#[cfg(test)]
+#[path = "tests.rs"]
+mod tests;
+
+const MAX_IRQS: usize = 256;
+
+pub struct IrqRoutingTable {
+    owners: [Option<ThreadId>; MAX_IRQS],
+}
+
+impl IrqRoutingTable {
+    pub fn new() -> Self {
+        Self {
+            owners: [None; MAX_IRQS],
+        }
+    }
+
+    pub fn register(&mut self, irq: IrqId, thread: ThreadId) -> Result<(), KernelError> {
+        let idx = irq.raw() as usize;
+        if self.owners[idx].is_some() {
+            return Err(KernelError::IrqAlreadyOwned(irq));
+        }
+        self.owners[idx] = Some(thread);
+        Ok(())
+    }
+
+    pub fn unregister(&mut self, irq: IrqId) {
+        self.owners[irq.raw() as usize] = None;
+    }
+
+    pub fn owner(&self, irq: IrqId) -> Option<ThreadId> {
+        self.owners[irq.raw() as usize]
+    }
+}
diff --git a/crates/domain/src/irq/tests.rs b/crates/domain/src/irq/tests.rs
new file mode 100644
index 0000000..2954b97
--- /dev/null
+++ b/crates/domain/src/irq/tests.rs
@@ -0,0 +1,50 @@
+use super::*;
+use types::id::{IrqId, ThreadId};
+
+fn irq(id: u16) -> IrqId {
+    IrqId::from_raw(id)
+}
+
+fn thread(id: u16) -> ThreadId {
+    ThreadId::from_raw(id)
+}
+
+#[test]
+fn new_table_has_no_owners() {
+    let table = IrqRoutingTable::new();
+    assert!(table.owner(irq(0)).is_none());
+    assert!(table.owner(irq(10)).is_none());
+}
+
+#[test]
+fn register_and_lookup() {
+    let mut table = IrqRoutingTable::new();
+    table.register(irq(5), thread(1)).unwrap();
+    assert_eq!(table.owner(irq(5)), Some(thread(1)));
+}
+
+#[test]
+fn register_already_owned_fails() {
+    let mut table = IrqRoutingTable::new();
+    table.register(irq(5), thread(1)).unwrap();
+    assert!(table.register(irq(5), thread(2)).is_err());
+}
+
+#[test]
+fn unregister_then_reregister() {
+    let mut table = IrqRoutingTable::new();
+    table.register(irq(5), thread(1)).unwrap();
+    table.unregister(irq(5));
+    assert!(table.owner(irq(5)).is_none());
+    table.register(irq(5), thread(2)).unwrap();
+    assert_eq!(table.owner(irq(5)), Some(thread(2)));
+}
+
+#[test]
+fn different_irqs_independent() {
+    let mut table = IrqRoutingTable::new();
+    table.register(irq(0), thread(10)).unwrap();
+    table.register(irq(1), thread(20)).unwrap();
+    assert_eq!(table.owner(irq(0)), Some(thread(10)));
+    assert_eq!(table.owner(irq(1)), Some(thread(20)));
+}
diff --git a/crates/platform/src/lib.rs b/crates/platform/src/lib.rs
index 78e7dd5..61f0091 100644
--- a/crates/platform/src/lib.rs
+++ b/crates/platform/src/lib.rs
@@ -1,6 +1,6 @@
 #![no_std]
 
-use domain::{resource::MemoryRegion, thread::SavedContext};
+use domain::{memory::MemoryRegion, thread::SavedContext};
 use types::{
     address::{EntryPoint, StackPointer},
     id::{CoreId, IrqId, ProcessId},