1 files changed, 10 insertions, 13 deletions

diff --git a/src/bindings.rs b/src/bindings.rs
index 4233528..ea35f57 100644
--- a/src/bindings.rs
+++ b/src/bindings.rs
@@ -294,20 +294,17 @@ impl Bindings {
 
     /// Find the binding matching a given scenario step, if there is
     /// exactly one.
-    pub fn find(&self, step: &ScenarioStep) -> Option<MatchedStep> {
+    pub fn find(&self, step: &ScenarioStep) -> Result<MatchedStep> {
         let mut matches = self
             .bindings()
             .iter()
-            .map(|b| b.match_with_step(step))
-            .filter(|o| o.is_some());
-        if let Some(m) = matches.next() {
-            if matches.count() == 0 {
-                m
-            } else {
-                None
-            }
-        } else {
-            None
+            .filter_map(|b| b.match_with_step(step));
+        match matches.next() {
+            None => Err(SubplotError::BindingUnknown(step.to_string())),
+            Some(matched) => match matches.next() {
+                None => Ok(matched),
+                Some(_) => Err(SubplotError::BindingNotUnique(step.to_string())),
+            },
         }
     }
 
@@ -441,7 +438,7 @@ mod test_bindings {
         let binding = Binding::new(StepKind::When, r"I am Tomjon", "set_foo", None).unwrap();
         let mut bindings = Bindings::new();
         bindings.add(&binding);
-        assert!(bindings.find(&step).is_none());
+        assert!(bindings.find(&step).is_err());
     }
 
     #[test]
@@ -451,7 +448,7 @@ mod test_bindings {
             Binding::new(StepKind::Given, r"I am Tomjon of Lancre", "set_foo", None).unwrap();
         let mut bindings = Bindings::new();
         bindings.add(&binding);
-        assert!(bindings.find(&step).is_none());
+        assert!(bindings.find(&step).is_err());
     }
 
     #[test]