1 files changed, 13 insertions, 0 deletions
diff --git a/src/doc.rs b/src/doc.rs
index 640968c..f08f795 100644
--- a/src/doc.rs
+++ b/src/doc.rs
@@ -265,12 +265,25 @@ impl Document {
     pub fn lint(&self) -> Result<(), SubplotError> {
         trace!("Linting document");
         self.check_doc_has_title()?;
+        self.check_scenarios_are_unique()?;
         self.check_filenames_are_unique()?;
         self.check_block_classes()?;
         trace!("No linting problems found");
         Ok(())
     }
 
+    // Check that all titles for scenarios are unique.
+    fn check_scenarios_are_unique(&self) -> Result<(), SubplotError> {
+        let mut known = HashSet::new();
+        for title in self.scenarios()?.iter().map(|s| s.title().to_lowercase()) {
+            if known.contains(&title) {
+                return Err(SubplotError::DuplicateScenario(title));
+            }
+            known.insert(title);
+        }
+        Ok(())
+    }
+
     // Check that all filenames for embedded files are unique.
     fn check_filenames_are_unique(&self) -> Result<(), SubplotError> {
         let mut known = HashSet::new();