Add tests for detect_plain_list.

src/parser/plain_list.rs

@@ -419,4 +419,40 @@ dolar"#,
 "#
         );
     }
+
+    #[test]
+    fn detect_line_break() {
+        let input = OrgSource::new(
+            r#"+
+"#,
+        );
+        let initial_context: ContextTree<'_, '_> = ContextTree::new();
+        let result = detect_plain_list(&initial_context, input);
+        assert!(result.is_ok());
+    }
+
+    #[test]
+    fn detect_eof() {
+        let input = OrgSource::new(r#"+"#);
+        let initial_context: ContextTree<'_, '_> = ContextTree::new();
+        let result = detect_plain_list(&initial_context, input);
+        assert!(result.is_ok());
+    }
+
+    #[test]
+    fn detect_no_gap() {
+        let input = OrgSource::new(r#"+foo"#);
+        let initial_context: ContextTree<'_, '_> = ContextTree::new();
+        let result = detect_plain_list(&initial_context, input);
+        // Since there is no whitespace after the '+' this is a paragraph, not a plain list.
+        assert!(result.is_err());
+    }
+
+    #[test]
+    fn detect_with_gap() {
+        let input = OrgSource::new(r#"+ foo"#);
+        let initial_context: ContextTree<'_, '_> = ContextTree::new();
+        let result = detect_plain_list(&initial_context, input);
+        assert!(result.is_ok());
+    }
 }