-Utilized Option instead of Vector to store IRQ lines for MMIO devices.

-Add test to test this.
-Update existing tests

Signed-off-by: Andrew Yao <[email protected]>
Co-authored-by: Himanshu Reddy <[email protected]>
Co-authored-by: Goldin Vo <[email protected]>

src/vmm/src/device_manager/mmio.rs

@@ -741,7 +741,6 @@ mod tests {
         assert_eq!(dummy.queues().len(), QUEUE_SIZES.len());
     }
 
-    // NOTE: we are also failing this test now 
     #[test]
     fn test_device_info() {
         let start_addr1 = GuestAddress(0x0);
@@ -820,30 +819,31 @@ mod tests {
     }
 
     #[test]
-    fn test_slot_irq_allocation() {
+    fn test_no_irq_allocation() {
         let mut device_manager = MMIODeviceManager::new();
         let mut resource_allocator = ResourceAllocator::new().unwrap();
+
         let device_info = device_manager
             .allocate_mmio_resources(&mut resource_allocator, 0)
             .unwrap();
         assert!(device_info.irq.is_none());
+    }
+
+    #[test]
+    fn test_irq_allocation() {
+        let mut device_manager = MMIODeviceManager::new();
+        let mut resource_allocator = ResourceAllocator::new().unwrap();
+
         let device_info = device_manager
             .allocate_mmio_resources(&mut resource_allocator, 1)
             .unwrap();
         assert_eq!(device_info.irq.unwrap().get(), crate::arch::IRQ_BASE);
-        assert_eq!(
-            format!(
-                "{}",
-                device_manager
-                    .allocate_mmio_resources(
-                        &mut resource_allocator,
-                        crate::arch::IRQ_MAX - crate::arch::IRQ_BASE + 1
-                    )
-                    .unwrap_err()
-            ),
-            "Invalid MMIO IRQ configuration."
-                .to_string()
-        );
+    }
+
+    #[test]
+    fn test_allocation_failure() {
+        let mut device_manager = MMIODeviceManager::new();
+        let mut resource_allocator = ResourceAllocator::new().unwrap();        
         assert_eq!(
             format!(
                 "{}",
@@ -854,8 +854,5 @@ mod tests {
             "Invalid MMIO IRQ configuration."
                 .to_string()
         );
-        device_manager
-            .allocate_mmio_resources(&mut resource_allocator, 0)
-            .unwrap();
     }
 }