Add a clean test (#20)

Author: matth2k

src/netlist.rs

@@ -1450,12 +1450,17 @@ where
     }
 
     /// Greedly removes unused nodes from the netlist, until it stops changing.
-    pub fn clean(&self) -> Result<(), String> {
-        let mut changed = true;
-        while changed {
-            changed = self.clean_once()?;
+    /// Returns true if the netlist was changed.
+    pub fn clean(&self) -> Result<bool, String> {
+        if !self.clean_once()? {
+            Ok(false)
+        } else {
+            let mut changed = true;
+            while changed {
+                changed = self.clean_once()?;
+            }
+            Ok(true)
         }
-        Ok(())
     }
 
     /// Returns `true` if all the nets are uniquely named

tests/edits.rs

@@ -0,0 +1,40 @@
+use safety_net::netlist::Gate;
+use safety_net::netlist::GateNetlist;
+use safety_net::netlist::Netlist;
+use std::rc::Rc;
+
+fn and_gate() -> Gate {
+    Gate::new_logical("AND".into(), vec!["A".into(), "B".into()], "Y".into())
+}
+
+fn get_simple_example() -> Rc<GateNetlist> {
+    let netlist = Netlist::new("example".to_string());
+
+    let a = netlist.insert_input("a".into());
+    let b = netlist.insert_input("b".into());
+
+    let instance = netlist
+        .insert_gate(and_gate(), "inst_0".into(), &[a, b])
+        .unwrap();
+
+    instance.expose_with_name("y".into());
+
+    netlist
+}
+
+#[test]
+fn test_clean() {
+    let netlist = get_simple_example();
+    assert!(netlist.verify().is_ok());
+    assert!(!netlist.clean().unwrap());
+    let inputs: Vec<_> = netlist.inputs().collect();
+    assert_eq!(inputs.len(), 2);
+    let _new_cell = netlist
+        .insert_gate(and_gate(), "inst_1".into(), &inputs)
+        .unwrap();
+    assert!(netlist.verify().is_ok());
+    assert_eq!(netlist.objects().count(), 4);
+    assert!(netlist.clean().unwrap());
+    assert_eq!(netlist.objects().count(), 3);
+    assert!(!netlist.clean().unwrap());
+}