Improve error message when run_command_async fails to find a command

test-helpers/src/lib.rs

@@ -6,7 +6,7 @@ pub mod mock_cassandra;
 pub mod shotover_process;
 mod test_tracing;
 
-use anyhow::{anyhow, Result};
+use anyhow::{anyhow, Error, Result};
 use std::path::Path;
 use subprocess::{Exec, Redirection};
 
@@ -38,16 +38,76 @@ pub fn run_command(command: &str, args: &[&str]) -> Result<String> {
     }
 }
 
+fn command_not_found_error(command: &str, args: &[&str]) -> Error {
+    // Maps a command to its associated dependency; however, if the name of the command and dependency is the same, we just use the command name.
+    // Currently, the only use case is mapping `npm` to its dependency `nodejs`.
+    let dependency = match command {
+        "npm" => "nodejs",
+        _ => command,
+    };
+
+    let args_part = if !args.is_empty() {
+        format!(" {}", args.join(" "))
+    } else {
+        String::new()
+    };
+
+    anyhow!(
+        "Attempted to run the command `{}{}` but {} does not exist. Have you installed {}?",
+        command,
+        args_part,
+        command,
+        dependency
+    )
+}
+
 pub async fn run_command_async(current_dir: &Path, command: &str, args: &[&str]) {
     let output = tokio::process::Command::new(command)
         .args(args)
         .current_dir(current_dir)
         .kill_on_drop(true)
         .status()
         .await
+        .map_err(|e| {
+            if e.kind() == std::io::ErrorKind::NotFound {
+                return command_not_found_error(command, args);
+            }
+
+            anyhow!(e)
+        })
         .unwrap();
 
     if !output.success() {
         panic!("command {command} {args:?} failed. See above output.")
     }
 }
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use futures_util::FutureExt;
+
+    #[tokio::test]
+    async fn test_run_command_async_not_found_message() {
+        let dir = Path::new(env!("CARGO_MANIFEST_DIR"));
+        let command = "shotover_non_existent_command";
+        let args = &["arg1", "arg2"];
+        let result = std::panic::AssertUnwindSafe(run_command_async(dir, command, args))
+            .catch_unwind()
+            .await;
+
+        assert!(result.is_err(), "Expected a panic but none occurred");
+
+        if let Err(panic_info) = result {
+            if let Some(error_message) = panic_info.downcast_ref::<String>() {
+                assert!(
+                    error_message.contains("Attempted to run the command `shotover_non_existent_command arg1 arg2` but shotover_non_existent_command does not exist. Have you installed shotover_non_existent_command?"),
+                    "Error message did not contain the expected NotFound error got: {}",
+                    error_message
+                );
+            } else {
+                panic!("Panic payload was not a string: {:?}", panic_info);
+            }
+        }
+    }
+}