1 files changed, 107 insertions, 2 deletions
diff --git a/var/shell-complete.rs b/var/shell-complete.rs
index 0a525d8..c69a426 100644
--- a/var/shell-complete.rs
+++ b/var/shell-complete.rs
@@ -52,8 +52,113 @@ pub struct Args {
   pub command: String,
 }
 
+fn generate_bash<W>(command: &str, output: &mut W)
+where
+  W: io::Write,
+{
+  let mut app = nitrocli::Args::clap();
+  app.gen_completions_to(command, clap::Shell::Bash, output);
+}
+
 fn main() {
   let args = Args::from_args();
-  let mut app = nitrocli::Args::clap();
-  app.gen_completions_to(&args.command, clap::Shell::Bash, &mut io::stdout());
+  generate_bash(&args.command, &mut io::stdout())
+}
+
+#[cfg(test)]
+mod tests {
+  use super::*;
+
+  use std::io;
+  use std::ops::Add as _;
+  use std::process;
+
+  /// Separate the given words by newlines.
+  fn lines<'w, W>(mut words: W) -> String
+  where
+    W: Iterator<Item = &'w str>,
+  {
+    let first = words.next().unwrap_or("");
+    words
+      .fold(first.to_string(), |words, word| {
+        format!("{}\n{}", words, word)
+      })
+      .add("\n")
+  }
+
+  /// Check if `bash` is present on the system.
+  fn has_bash() -> bool {
+    match process::Command::new("bash").arg("-c").arg("exit").spawn() {
+      // We deliberately only indicate that bash does not exist if we
+      // get a file-not-found error. We don't expect any other error but
+      // should there be one things will blow up later.
+      Err(ref err) if err.kind() == io::ErrorKind::NotFound => false,
+      _ => true,
+    }
+  }
+
+  /// Perform a bash completion of the given arguments to nitrocli.
+  fn complete_bash<'w, W>(words: W) -> Vec<u8>
+  where
+    W: ExactSizeIterator<Item = &'w str>,
+  {
+    let mut buffer = Vec::new();
+    generate_bash("nitrocli", &mut buffer);
+
+    let script = String::from_utf8(buffer).unwrap();
+    let command = format!(
+      "
+set -e;
+eval '{script}';
+export COMP_WORDS=({words});
+export COMP_CWORD={index};
+_nitrocli;
+echo -n ${{COMPREPLY}}
+      ",
+      index = words.len(),
+      words = lines(Some("nitrocli").into_iter().chain(words)),
+      script = script
+    );
+
+    let output = process::Command::new("bash")
+      .arg("-c")
+      .arg(command)
+      .output()
+      .unwrap();
+
+    output.stdout
+  }
+
+  #[test]
+  fn array_lines() {
+    assert_eq!(&lines(vec![].into_iter()), "\n");
+    assert_eq!(&lines(vec!["first"].into_iter()), "first\n");
+    assert_eq!(
+      &lines(vec!["first", "second"].into_iter()),
+      "first\nsecond\n"
+    );
+    assert_eq!(
+      &lines(vec!["first", "second", "third"].into_iter()),
+      "first\nsecond\nthird\n"
+    );
+  }
+
+  #[test]
+  fn complete_all_the_things() {
+    if !has_bash() {
+      return;
+    }
+
+    assert_eq!(complete_bash(vec!["stat"].into_iter()), b"status");
+    assert_eq!(
+      complete_bash(vec!["status", "--ver"].into_iter()),
+      b"--version"
+    );
+    assert_eq!(complete_bash(vec!["--version"].into_iter()), b"--version");
+    assert_eq!(complete_bash(vec!["--model", "s"].into_iter()), b"storage");
+    assert_eq!(
+      complete_bash(vec!["otp", "get", "--model", "p"].into_iter()),
+      b"pro"
+    );
+  }
 }