Fix using --help, --verbose, etc. (rust-lang#3620)

Author: ehuss

src/cargo-fmt/main.rs

@@ -85,7 +85,14 @@ fn execute() -> i32 {
     };
 
     if opts.version {
-        return handle_command_status(get_version());
+        return handle_command_status(get_rustfmt_info(&[String::from("--version")]));
+    }
+    if opts.rustfmt_options.iter().any(|s| {
+        ["--print-config", "-h", "--help", "-V", "--version"].contains(&s.as_str())
+            || s.starts_with("--help=")
+            || s.starts_with("--print-config=")
+    }) {
+        return handle_command_status(get_rustfmt_info(&opts.rustfmt_options));
     }
 
     let strategy = CargoFmtStrategy::from_opts(&opts);
@@ -118,10 +125,10 @@ fn handle_command_status(status: Result<i32, io::Error>) -> i32 {
     }
 }
 
-fn get_version() -> Result<i32, io::Error> {
+fn get_rustfmt_info(args: &[String]) -> Result<i32, io::Error> {
     let mut command = Command::new("rustfmt")
         .stdout(std::process::Stdio::inherit())
-        .args(&[String::from("--version")])
+        .args(args)
         .spawn()
         .map_err(|e| match e.kind() {
             io::ErrorKind::NotFound => io::Error::new(
@@ -143,14 +150,7 @@ fn format_crate(
     strategy: &CargoFmtStrategy,
     rustfmt_args: Vec<String>,
 ) -> Result<i32, io::Error> {
-    let targets = if rustfmt_args
-        .iter()
-        .any(|s| ["--print-config", "-h", "--help", "-V", "--version"].contains(&s.as_str()))
-    {
-        BTreeSet::new()
-    } else {
-        get_targets(strategy)?
-    };
+    let targets = get_targets(strategy)?;
 
     // Currently only bin and lib files get formatted.
     run_rustfmt(&targets, &rustfmt_args, verbosity)

tests/cargo-fmt/main.rs

@@ -0,0 +1,70 @@
+// Integration tests for cargo-fmt.
+
+use std::env;
+use std::process::Command;
+
+/// Run the cargo-fmt executable and return its output.
+fn cargo_fmt(args: &[&str]) -> (String, String) {
+    let mut bin_dir = env::current_exe().unwrap();
+    bin_dir.pop(); // chop off test exe name
+    if bin_dir.ends_with("deps") {
+        bin_dir.pop();
+    }
+    let cmd = bin_dir.join(format!("cargo-fmt{}", env::consts::EXE_SUFFIX));
+
+    // Ensure cargo-fmt runs the rustfmt binary from the local target dir.
+    let path = env::var_os("PATH").unwrap_or_default();
+    let mut paths = env::split_paths(&path).collect::<Vec<_>>();
+    paths.insert(0, bin_dir);
+    let new_path = env::join_paths(paths).unwrap();
+
+    match Command::new(&cmd).args(args).env("PATH", new_path).output() {
+        Ok(output) => (
+            String::from_utf8(output.stdout).expect("utf-8"),
+            String::from_utf8(output.stderr).expect("utf-8"),
+        ),
+        Err(e) => panic!("failed to run `{:?} {:?}`: {}", cmd, args, e),
+    }
+}
+
+macro_rules! assert_that {
+    ($args:expr, $check:ident $check_args:tt) => {
+        let (stdout, stderr) = cargo_fmt($args);
+        if !stdout.$check$check_args {
+            panic!(
+                "Output not expected for cargo-fmt {:?}\n\
+                 expected: {}{}\n\
+                 actual stdout:\n{}\n\
+                 actual stderr:\n{}",
+                $args,
+                stringify!($check),
+                stringify!($check_args),
+                stdout,
+                stderr
+            );
+        }
+    };
+}
+
+#[test]
+fn version() {
+    assert_that!(&["--version"], starts_with("rustfmt "));
+    assert_that!(&["--version"], starts_with("rustfmt "));
+    assert_that!(&["--", "-V"], starts_with("rustfmt "));
+    assert_that!(&["--", "--version"], starts_with("rustfmt "));
+}
+
+#[test]
+fn print_config() {
+    assert_that!(
+        &["--", "--print-config", "current", "."],
+        contains("max_width = ")
+    );
+}
+
+#[test]
+fn rustfmt_help() {
+    assert_that!(&["--", "--help"], contains("Format Rust code"));
+    assert_that!(&["--", "-h"], contains("Format Rust code"));
+    assert_that!(&["--", "--help=config"], contains("Configuration Options:"));
+}