Add a test for footnote definition.

src/parser/footnote_definition.rs

@@ -84,3 +84,43 @@ fn footnote_definition_end<'r, 's>(
         ))),
     ))(input)
 }
+
+#[cfg(test)]
+mod tests {
+    use crate::parser::parser_context::ContextElement;
+    use crate::parser::parser_context::ContextTree;
+    use crate::parser::parser_with_context::parser_with_context;
+
+    use super::*;
+
+    #[test]
+    fn two_paragraphs() {
+        let input = "[fn:1] A footnote.
+
+[fn:2] A multi-
+
+line footnote.";
+        let initial_context: ContextTree<'_, '_> = ContextTree::new();
+        let document_context =
+            initial_context.with_additional_node(ContextElement::DocumentRoot(input));
+        let footnote_definition_matcher =
+            parser_with_context!(footnote_definition)(&document_context);
+        let (remaining, first_footnote_definition) =
+            footnote_definition_matcher(input).expect("Parse first footnote_definition");
+        let (remaining, second_footnote_definition) =
+            footnote_definition_matcher(remaining).expect("Parse second footnote_definition.");
+        assert_eq!(remaining, "");
+        assert_eq!(
+            first_footnote_definition.source,
+            "[fn:1] A footnote.
+
+"
+        );
+        assert_eq!(
+            second_footnote_definition.source,
+            "[fn:2] A multi-
+
+line footnote."
+        );
+    }
+}