1 files changed, 16 insertions, 8 deletions

diff --git a/subplotlib/src/step.rs b/subplotlib/src/step.rs
index bbea249..76b9193 100644
--- a/subplotlib/src/step.rs
+++ b/subplotlib/src/step.rs
@@ -10,6 +10,8 @@ use std::panic::{catch_unwind, AssertUnwindSafe};
 use crate::scenario::{Scenario, ScenarioContext};
 use crate::types::StepResult;
 
+type StepFunc = dyn Fn(&ScenarioContext, bool) -> StepResult;
+
 /// A ScenarioStep is one step in a scenario.
 ///
 /// In essence, a scenario step is a named closure.  Its name can be used when
@@ -23,12 +25,13 @@ use crate::types::StepResult;
 /// # use subplotlib::prelude::*;
 ///
 /// let step = ScenarioStep::new(
-///     "when everything works".to_string(), |ctx, ok| Ok(()), |scen| ()
+///     "when everything works".to_string(), |ctx, ok| Ok(()), |scen| (), "unknown"
 /// );
 /// ```
 pub struct ScenarioStep {
     step_text: String,
-    func: Box<dyn Fn(&ScenarioContext, bool) -> StepResult>,
+    location: &'static str,
+    func: Box<StepFunc>,
     reg: Box<dyn Fn(&Scenario)>,
 }
 
@@ -38,13 +41,14 @@ impl ScenarioStep {
     /// This is used to construct a scenario step from a function which
     /// takes the scenario context container.  This will generally be
     /// called from the generated build method for the step.
-    pub fn new<F, R>(step_text: String, func: F, reg: R) -> Self
+    pub fn new<F, R>(step_text: String, func: F, reg: R, location: &'static str) -> Self
     where
         F: Fn(&ScenarioContext, bool) -> StepResult + 'static,
         R: Fn(&Scenario) + 'static,
     {
         Self {
             step_text,
+            location,
             func: Box::new(func),
             reg: Box::new(reg),
         }
@@ -53,13 +57,13 @@ impl ScenarioStep {
     /// Attempt to render a message.
     /// If something panics with a type other than a static string or
     /// a formatted string then we won't be able to render it sadly.
-    fn render_panic(name: &str, err: Box<dyn Any + Send>) -> String {
+    fn render_panic(location: &str, name: &str, err: Box<dyn Any + Send>) -> String {
         if let Some(msg) = err.downcast_ref::<&str>() {
-            format!("step {} panic'd: {}", name, msg)
+            format!("{location}: step {name} panic'd: {msg}")
         } else if let Some(msg) = err.downcast_ref::<String>() {
-            format!("step {} panic'd: {}", name, msg)
+            format!("{location}: step {name} panic'd: {msg}")
         } else {
-            format!("step {} panic'd", name)
+            format!("{location}: step {name} panic'd")
         }
     }
 
@@ -71,7 +75,7 @@ impl ScenarioStep {
         // subsequent step calls may not be sound.  There's not a lot we can
         // do to ensure things are good except try.
         let func = AssertUnwindSafe(|| (*self.func)(context, defuse_poison));
-        catch_unwind(func).map_err(|e| Self::render_panic(self.step_text(), e))?
+        catch_unwind(func).map_err(|e| Self::render_panic(self.location(), self.step_text(), e))?
     }
 
     /// Return the full text of this step
@@ -83,4 +87,8 @@ impl ScenarioStep {
     pub(crate) fn register_contexts(&self, scenario: &Scenario) {
         (*self.reg)(scenario);
     }
+
+    pub(crate) fn location(&self) -> &'static str {
+        self.location
+    }
 }