exclude test module when not running tests

Author: tisonkun

src/lib.rs

@@ -121,6 +121,7 @@ use std::str::FromStr;
 
 use unicode_width::UnicodeWidthStr;
 
+#[cfg(test)]
 mod tests;
 
 /// A description of the options that a program can handle.
@@ -977,4 +978,4 @@ fn each_split_within(desc: &str, lim: usize) -> Vec<String> {
         }
     }
     rows
-}
+}