diff --git a/src/manager/user.rs b/src/manager/user.rs
index 65b8ca4..fe5c667 100644
--- a/src/manager/user.rs
+++ b/src/manager/user.rs
@@ -395,14 +395,10 @@ mod test {
     use crate::daemon::user::UserContext;
     use crate::testing;
 
-    use std::collections::{HashMap, HashSet};
-    use std::iter::zip;
     use std::time::Duration;
-    use tokio::fs::read;
     use tokio::sync::mpsc::unbounded_channel;
     use tokio::time::sleep;
-    use zbus::{Connection, Interface};
-    use zbus_xml::{Method, Node, Property};
+    use zbus::Connection;
 
     struct TestHandle {
         _handle: testing::TestHandle,
@@ -429,96 +425,22 @@ mod test {
         })
     }
 
-    fn collect_methods<'a>(methods: &'a [Method<'a>]) -> HashMap<String, &'a Method<'a>> {
-        let mut map = HashMap::new();
-        for method in methods.iter() {
-            map.insert(method.name().to_string(), method);
-        }
-        map
-    }
-
-    fn collect_properties<'a>(props: &'a [Property<'a>]) -> HashMap<String, &'a Property<'a>> {
-        let mut map = HashMap::new();
-        for prop in props.iter() {
-            map.insert(prop.name().to_string(), prop);
-        }
-        map
-    }
-
     #[tokio::test]
     async fn interface_matches() {
         let test = start().await.expect("start");
 
-        let manager_ref = test
-            .connection
-            .object_server()
-            .interface::<_, SteamOSManager>("/com/steampowered/SteamOSManager1")
-            .await
-            .expect("interface");
-        let manager = manager_ref.get().await;
-        let mut remote_interface_string = String::from(
-            "<node name=\"/\" xmlns:doc=\"http://www.freedesktop.org/dbus/1.0/doc.dtd\">",
-        );
-        manager.introspect_to_writer(&mut remote_interface_string, 0);
-        remote_interface_string.push_str("</node>");
-        let remote_interfaces =
-            Node::from_reader::<&[u8]>(remote_interface_string.as_bytes()).expect("from_reader");
-        let remote_interface: Vec<_> = remote_interfaces
-            .interfaces()
-            .iter()
-            .filter(|iface| iface.name() == "com.steampowered.SteamOSManager1.Manager")
-            .collect();
-        assert_eq!(remote_interface.len(), 1);
-        let remote_interface = remote_interface[0];
-        let remote_methods = collect_methods(remote_interface.methods());
-        let remote_method_names: HashSet<&String> = remote_methods.keys().collect();
-        let remote_properties = collect_properties(remote_interface.properties());
-        let remote_property_names: HashSet<&String> = remote_properties.keys().collect();
-
-        let local_interface_string = read("com.steampowered.SteamOSManager1.Manager.xml")
-            .await
-            .expect("read");
-        let local_interfaces =
-            Node::from_reader::<&[u8]>(local_interface_string.as_ref()).expect("from_reader");
-        let local_interface: Vec<_> = local_interfaces
-            .interfaces()
-            .iter()
-            .filter(|iface| iface.name() == "com.steampowered.SteamOSManager1.Manager")
-            .collect();
-        assert_eq!(local_interface.len(), 1);
-        let local_interface = local_interface[0];
-        let local_methods = collect_methods(local_interface.methods());
-        let local_method_names: HashSet<&String> = local_methods.keys().collect();
-        let local_properties = collect_properties(local_interface.properties());
-        let local_property_names: HashSet<&String> = local_properties.keys().collect();
-
-        for key in local_method_names.union(&remote_method_names) {
-            let local_method = local_methods.get(*key).expect(key);
-            let remote_method = remote_methods.get(*key).expect(key);
-
-            assert_eq!(local_method.name(), remote_method.name());
-            assert_eq!(
-                local_method.args().len(),
-                remote_method.args().len(),
-                "Testing {:?} against {:?}",
-                local_method,
-                remote_method
-            );
-            for (local_arg, remote_arg) in
-                zip(local_method.args().iter(), remote_method.args().iter())
-            {
-                assert_eq!(local_arg.direction(), remote_arg.direction());
-                assert_eq!(local_arg.ty(), remote_arg.ty());
-            }
-        }
-
-        for key in local_property_names.union(&remote_property_names) {
-            let local_property = local_properties.get(*key).expect(key);
-            let remote_property = remote_properties.get(*key).expect(key);
-
-            assert_eq!(local_property.name(), remote_property.name());
-            assert_eq!(local_property.ty(), remote_property.ty());
-            assert_eq!(local_property.access(), remote_property.access());
-        }
+        let remote = testing::InterfaceIntrospection::from_remote::<SteamOSManager, _>(
+            &test.connection,
+            "/com/steampowered/SteamOSManager1",
+        )
+        .await
+        .expect("remote");
+        let local = testing::InterfaceIntrospection::from_local(
+            "com.steampowered.SteamOSManager1.Manager.xml",
+            "com.steampowered.SteamOSManager1.Manager",
+        )
+        .await
+        .expect("local");
+        assert!(remote.compare(&local));
     }
 }
diff --git a/src/testing.rs b/src/testing.rs
index cc1fe8e..cc5399c 100644
--- a/src/testing.rs
+++ b/src/testing.rs
@@ -4,17 +4,23 @@ use nix::sys::signal;
 use nix::sys::signal::Signal;
 use nix::unistd::Pid;
 use std::cell::{Cell, RefCell};
+use std::collections::{HashMap, HashSet};
 use std::ffi::OsStr;
+use std::iter::zip;
 use std::path::Path;
 use std::process::Stdio;
 use std::rc::Rc;
 use std::str::FromStr;
 use std::time::Duration;
 use tempfile::{tempdir, TempDir};
+use tokio::fs::read;
 use tokio::io::{AsyncBufReadExt, BufReader};
 use tokio::process::{Child, Command};
 use tokio::sync::Mutex;
-use zbus::{Address, Connection, ConnectionBuilder};
+use tracing::error;
+use zbus::zvariant::ObjectPath;
+use zbus::{Address, Connection, ConnectionBuilder, Interface};
+use zbus_xml::{Method, Node, Property};
 
 thread_local! {
     static TEST: RefCell<Option<Rc<Test>>> = RefCell::new(None);
@@ -174,3 +180,170 @@ impl Drop for TestHandle {
         stop();
     }
 }
+
+pub struct InterfaceIntrospection<'a> {
+    interface: zbus_xml::Interface<'a>,
+}
+
+impl<'a> InterfaceIntrospection<'a> {
+    pub async fn from_remote<'p, I, P>(connection: &Connection, path: P) -> Result<Self>
+    where
+        I: Interface,
+        P: TryInto<ObjectPath<'p>>,
+        P::Error: Into<zbus::Error>,
+    {
+        let iface_ref = connection.object_server().interface::<_, I>(path).await?;
+        let iface = iface_ref.get().await;
+        let mut remote_interface_string = String::from(
+            "<node name=\"/\" xmlns:doc=\"http://www.freedesktop.org/dbus/1.0/doc.dtd\">",
+        );
+        iface.introspect_to_writer(&mut remote_interface_string, 0);
+        remote_interface_string.push_str("</node>");
+        Self::from_xml(remote_interface_string.as_bytes(), I::name().to_string())
+    }
+
+    pub async fn from_local<'p, P: AsRef<Path>, S: AsRef<str>>(
+        path: P,
+        interface: S,
+    ) -> Result<Self> {
+        let local_interface_string = read(path.as_ref()).await?;
+        Self::from_xml(local_interface_string.as_ref(), interface)
+    }
+
+    fn from_xml<S: AsRef<str>>(xml: &[u8], iface_name: S) -> Result<Self> {
+        let node = Node::from_reader(xml)?;
+        let interfaces = node.interfaces();
+        let mut interface = None;
+        for iface in interfaces {
+            if iface.name() == iface_name.as_ref() {
+                interface = Some(iface.clone());
+                break;
+            }
+        }
+        Ok(if let Some(interface) = interface {
+            InterfaceIntrospection { interface }
+        } else {
+            bail!("No interface found");
+        })
+    }
+
+    fn collect_methods(&self) -> HashMap<String, &Method<'_>> {
+        let mut map = HashMap::new();
+        for method in self.interface.methods().iter() {
+            map.insert(method.name().to_string(), method);
+        }
+        map
+    }
+
+    fn collect_properties(&self) -> HashMap<String, &Property<'_>> {
+        let mut map = HashMap::new();
+        for prop in self.interface.properties().iter() {
+            map.insert(prop.name().to_string(), prop);
+        }
+        map
+    }
+
+    fn compare_methods(&self, other: &InterfaceIntrospection<'_>) -> u32 {
+        let local_methods = self.collect_methods();
+        let local_method_names: HashSet<&String> = local_methods.keys().collect();
+        let other_methods = other.collect_methods();
+        let other_method_names: HashSet<&String> = other_methods.keys().collect();
+
+        let mut issues = 0;
+
+        for key in local_method_names.union(&other_method_names) {
+            let local_method = match local_methods.get(*key) {
+                None => {
+                    error!("Method {key} missing on self");
+                    issues += 1;
+                    continue;
+                }
+                Some(method) => method,
+            };
+
+            let other_method = match other_methods.get(*key) {
+                None => {
+                    error!("Method {key} missing on other");
+                    issues += 1;
+                    continue;
+                }
+                Some(method) => method,
+            };
+
+            if local_method.args().len() != other_method.args().len() {
+                error!("Different arguments between {local_method:?} and {other_method:?}");
+                issues += 1;
+                continue;
+            }
+
+            for (local_arg, other_arg) in
+                zip(local_method.args().iter(), other_method.args().iter())
+            {
+                if local_arg.direction() != other_arg.direction() {
+                    error!("Arguments {local_arg:?} and {other_arg:?} differ in direction");
+                    issues += 1;
+                    continue;
+                }
+                if local_arg.ty() != other_arg.ty() {
+                    error!("Arguments {local_arg:?} and {other_arg:?} differ in type");
+                    issues += 1;
+                    continue;
+                }
+            }
+        }
+
+        issues
+    }
+
+    fn compare_properties(&self, other: &InterfaceIntrospection<'_>) -> u32 {
+        let local_properties = self.collect_properties();
+        let local_property_names: HashSet<&String> = local_properties.keys().collect();
+
+        let other_properties = other.collect_properties();
+        let other_property_names: HashSet<&String> = other_properties.keys().collect();
+
+        let mut issues = 0;
+
+        for key in local_property_names.union(&other_property_names) {
+            let local_property = match local_properties.get(*key) {
+                None => {
+                    error!("Property {key} missing on self");
+                    issues += 1;
+                    continue;
+                }
+                Some(prop) => prop,
+            };
+
+            let other_property = match other_properties.get(*key) {
+                None => {
+                    error!("Property {key} missing on other");
+                    issues += 1;
+                    continue;
+                }
+                Some(prop) => prop,
+            };
+
+            if local_property.ty() != other_property.ty() {
+                error!("Properties {local_property:?} and {other_property:?} differ in type");
+                issues += 1;
+                continue;
+            }
+
+            if local_property.access() != other_property.access() {
+                error!("Properties {local_property:?} and {other_property:?} differ in access");
+                issues += 1;
+                continue;
+            }
+        }
+
+        issues
+    }
+
+    pub fn compare(&self, other: &InterfaceIntrospection<'_>) -> bool {
+        let mut issues = 0;
+        issues += self.compare_methods(other);
+        issues += self.compare_properties(other);
+
+        issues == 0
+    }
+}