Introduce a glorious new cli arg splitter

Allow &str and &[&str] as input for `command`

Fixes #25

src/lib.rs

@@ -119,6 +119,9 @@ pub use macros::flatten_escaped_string;
 mod output;
 use output::{OutputAssertion, StdErr, StdOut};
 
+mod parse_cmd;
+use parse_cmd::ToCmd;
+
 mod diff;
 
 /// Assertions for a specific command.
@@ -178,9 +181,16 @@ impl Assert {
     /// assert_cli::Assert::command(&["echo", "1337"])
     ///     .unwrap();
     /// ```
-    pub fn command(cmd: &[&str]) -> Self {
+    ///
+    /// ```rust
+    /// extern crate assert_cli;
+    ///
+    /// assert_cli::Assert::command("echo 1337")
+    ///     .unwrap();
+    /// ```
+    pub fn command<'a, T: ToCmd<'a> + ?Sized>(cmd: &'a T) -> Self {
         Assert {
-            cmd: cmd.into_iter().cloned().map(String::from).collect(),
+            cmd: cmd.to_cmd(),
             ..Self::default()
         }
     }

src/parse_cmd.rs

@@ -0,0 +1,98 @@
+pub trait ToCmd<'a> {
+    fn to_cmd(&'a self) -> Vec<String>;
+}
+
+impl<'a> ToCmd<'a> for str {
+    fn to_cmd(&'a self) -> Vec<String> {
+        let mut args = Vec::new();
+        let mut current_arg = String::new();
+        let mut in_quote = Vec::new();
+
+        for c in self.chars() {
+            if in_quote.is_empty() && c.is_whitespace() {
+                args.push(current_arg);
+                current_arg = String::new();
+                continue;
+            }
+
+            current_arg.push(c);
+
+            if c == '"' || c == '\'' {
+                if in_quote.last() == Some(&c) {
+                    in_quote.pop();
+                } else {
+                    in_quote.push(c);
+                }
+            }
+        }
+
+        if !current_arg.is_empty() {
+            args.push(current_arg);
+        }
+
+        args
+    }
+}
+
+impl<'a, 'b, T> ToCmd<'a> for T where
+    &'a T: AsRef<[&'b str]>,
+    T: 'a,
+{
+    fn to_cmd(&'a self) -> Vec<String> {
+        self.as_ref().into_iter().map(|x| x.to_string()).collect()
+    }
+}
+
+#[cfg(test)]
+mod test {
+    use super::ToCmd;
+
+    #[test]
+    fn slices() {
+        assert_eq!(
+            ToCmd::to_cmd(&["echo", "42"]),
+            vec!["echo", "42"]
+        );
+    }
+
+    #[test]
+    fn simple() {
+        assert_eq!(
+            "echo 42".to_cmd(),
+            vec!["echo", "42"]
+        );
+        assert_eq!(
+            r#"echo "42""#.to_cmd(),
+            vec!["echo", "\"42\""]
+        );
+        assert_eq!(
+            r#"echo '42'"#.to_cmd(),
+            vec!["echo", "\'42\'"]
+        );
+        assert_eq!(
+            r#"echo '42 is the answer'"#.to_cmd(),
+            vec!["echo", "\'42 is the answer\'"]
+        );
+    }
+
+    #[test]
+    fn real_world() {
+        assert_eq!(
+            r#"cargo run --bin whatever -- --input="Lorem ipsum" -f"#.to_cmd(),
+            vec!["cargo", "run", "--bin", "whatever",  "--", "--input=\"Lorem ipsum\"", "-f"]
+        );
+    }
+
+    #[test]
+    fn nested_quotes() {
+        assert_eq!(
+            r#"echo "lorem ipsum 'dolor' sit amet""#.to_cmd(),
+            vec!["echo", "\"lorem ipsum 'dolor' sit amet\""]
+        );
+
+        assert_eq!(
+            r#"echo "lorem ipsum ('dolor "doloris" septetur') sit amet""#.to_cmd(),
+            vec!["echo", "\"lorem ipsum ('dolor \"doloris\" septetur') sit amet\""]
+        );
+    }
+}