Camel keep beginning and doubled underscores

src/segment.rs

@@ -208,6 +208,8 @@ pub(crate) fn paste(segments: &[Segment]) -> Result<String> {
                                 } else {
                                     acc.push(ch);
                                 }
+                            } else if prev == '_' {
+                                acc.push(ch);
                             }
                             prev = ch;
                         }

tests/test_item.rs

@@ -153,14 +153,23 @@ mod test_to_camel {
         };
     }
 
-    m!(this_is_but_a_test);
-
     #[test]
     fn test_to_camel() {
+        m!(this_is_but_a_test);
+
         assert_eq!(DEFAULT_CAMEL, "ThisIsButATest");
         assert_eq!(LOWER_CAMEL, "thisisbutatest");
         assert_eq!(UPPER_CAMEL, "THISISBUTATEST");
     }
+
+    #[test]
+    fn test_to_camel_with_underscores() {
+        m!(__this_is_but__a_test);
+
+        assert_eq!(DEFAULT_CAMEL, "__ThisIsBut_ATest");
+        assert_eq!(LOWER_CAMEL, "__thisisbut_atest");
+        assert_eq!(UPPER_CAMEL, "__THISISBUT_ATEST");
+    }
 }
 
 mod test_doc_expr {