fix(completion): fix the generation of completion for shells

src/app.rs

@@ -2,10 +2,10 @@ use std::ffi::OsString;
 use std::io;
 use std::str::FromStr;
 
-use clap_complete::{generate, Shell};
 use log::LevelFilter;
 
 use crate::cli::build_cli;
+use crate::cmd::execute_completion;
 use crate::cmd::execute_diagram_generate;
 use crate::cmd::execute_library_generate;
 
@@ -80,17 +80,13 @@ where
             }
         },
         Some(("completion", m)) => {
-            let shell = m
-                .get_one::<String>("SHELL")
-                .map(|v| Shell::from_str(v).unwrap())
-                .unwrap();
-            generate(
-                shell,
-                &mut build_cli(),
-                "plantuml-generator",
-                &mut io::stdout(),
-            );
-            return 1;
+            return match execute_completion(m) {
+                Ok(_) => 0,
+                Err(e) => {
+                    log::error!("the command failed: {}", e);
+                    2
+                }
+            };
         }
         _ => {
             log::warn!("the SUBCOMMAND is missing");

src/cmd/completion/mod.rs

@@ -0,0 +1,30 @@
+use std::io;
+
+use clap::ArgMatches;
+use clap_complete::{generate, Shell};
+
+use crate::cli::build_cli;
+use crate::result::Result;
+
+pub fn execute_completion(arg_matches: &ArgMatches) -> Result<()> {
+    let shell = arg_matches.get_one::<Shell>("SHELL").unwrap();
+    generate(
+        *shell,
+        &mut build_cli(),
+        "plantuml-generator",
+        &mut io::stdout(),
+    );
+    Ok(())
+}
+
+#[cfg(test)]
+mod test {
+    use super::*;
+
+    #[test]
+    fn test_completion() {
+        let arg_matches =
+            build_cli().get_matches_from(["plantuml-generator", "-l=Debug", "completion", "bash"]);
+        execute_completion(arg_matches.subcommand_matches("completion").unwrap()).unwrap();
+    }
+}

src/cmd/mod.rs

@@ -1,5 +1,7 @@
+pub use self::completion::execute_completion;
 pub use self::diagram::execute_diagram_generate;
 pub use self::library::execute_library_generate;
 
+mod completion;
 mod diagram;
 mod library;