Added --output_file option

- added #cfg[test] block for main.rs

Cargo.toml

@@ -28,6 +28,9 @@ chrono = "*"
 inferno = "*"
 primal = "0.3"
 
+[dev-dependencies]
+assert_cmd = { version = "2" }
+expect-test = { version = "1.4" }
 
 [build-dependencies]
 bindgen = "*"

src/main.rs

@@ -72,6 +72,9 @@ struct Cli {
       value_parser = sample_freq_in_range,
     )]
     sample_freq: u16,
+    /// Output file for Flame Graph in SVG format
+    #[arg(short, long, default_value = "flame.svg")]
+    output_file: PathBuf,
 }
 
 fn main() -> Result<(), Box<dyn Error>> {
@@ -128,15 +131,25 @@ fn main() -> Result<(), Box<dyn Error>> {
 
     let mut options: flamegraph::Options<'_> = flamegraph::Options::default();
     let data = folded.as_bytes();
-    let flame_path = "flame.svg";
+    let flame_path = args.output_file;
     let f = File::create(flame_path).unwrap();
     flamegraph::from_reader(&mut options, data, f).unwrap();
 
     Ok(())
 }
 
-#[test]
-fn verify_cli() {
-    use clap::CommandFactory;
-    Cli::command().debug_assert()
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use assert_cmd::Command;
+    use expect_test::expect;
+
+    #[test]
+    fn verify_cli() {
+        use clap::CommandFactory;
+        Cli::command().debug_assert()
+    }
+
+    #[test]
+    fn duration_arg() {}
 }