check branch name is not empty (fix #26)

src/argv.rs

@@ -240,6 +240,9 @@ impl Parsed {
         let cwd = get_cwd(matches.opt_str("d"))?;
         let git = Git::new(&cwd, &env.git_command);
         let branch = if let Some(b) = matches.opt_str("b") {
+            if b.is_empty() {
+                return Error::err(ErrorKind::BranchNameEmpty);
+            }
             Some(b)
         } else if matches.opt_present("c") {
             Some(git.current_branch()?)

src/error.rs

@@ -166,6 +166,7 @@ pub enum ErrorKind {
     SpecifiedDirNotExist {
         dir: String,
     },
+    BranchNameEmpty,
 }
 
 impl fmt::Display for ErrorKind {
@@ -223,6 +224,7 @@ impl fmt::Display for ErrorKind {
             CannotBlameDirectory{dir} => write!(f, "Cannot blame directory '{}'. Please specify file path", dir),
             UserBrowseCommandFailed{cmd, url, msg} => write!(f, "Command '{}' failed to open URL {}. Please check $GIT_BRWS_BROWSE_COMMAND. stderr: {}", cmd, url, msg),
             SpecifiedDirNotExist{dir} => write!(f, "Specified directory '{}' with -d option does not exist", dir),
+            BranchNameEmpty => write!(f, "Branch name cannot be empty"),
         }
     }
 }

src/test/argv.rs

@@ -260,3 +260,11 @@ fn current_branch_flag() {
         p => panic!("{:?}", p),
     }
 }
+
+// #26
+#[test]
+fn branch_name_is_empty() {
+    let e = Parsed::parse_iter(&["git-brws", "-b", ""]).unwrap_err();
+    let k = e.kind();
+    assert!(matches!(k, ErrorKind::BranchNameEmpty), "{:?}", k);
+}