tests: Add tests related to #706

Try and stress the combinations of DeriveDisplayOrder and UnifiedHelpMessage
along with propagating them to subcommands and explicitly setting a display
order.

The new tests

  derive_order_subcommand_propagate
  unified_help_and_derive_order_subcommand_propagate
  unified_help_and_derive_order_subcommand_propagate_with_explicit_display_order

are currently failing because of bug #706.

tests/derive_order.rs

@@ -0,0 +1,249 @@
+extern crate clap;
+
+use std::str;
+
+use clap::{App, Arg, SubCommand, AppSettings};
+
+fn condense_whitespace(s: &str) -> String {
+    s.split_whitespace().collect::<Vec<_>>().join(" ")
+}
+
+fn normalize(s: &str) -> Vec<String> {
+    s.lines().map(|l| l.trim()).filter(|l| !l.is_empty()).map(condense_whitespace).collect()
+}
+
+fn get_help(app: App, args: &[&'static str]) -> Vec<String> {
+    let res = app.get_matches_from_safe(args.iter().chain(["--help"].iter()));
+    normalize(&*res.unwrap_err().message)
+}
+
+#[test]
+fn no_derive_order() {
+    let app = App::new("test")
+        .args(&[
+            Arg::with_name("flag_b").long("flag_b").help("first flag"),
+            Arg::with_name("option_b").long("option_b").takes_value(true).help("first option"),
+            Arg::with_name("flag_a").long("flag_a").help("second flag"),
+            Arg::with_name("option_a").long("option_a").takes_value(true).help("second option"),
+        ]);
+
+    assert_eq!(get_help(app, &["test"]), normalize("
+        test
+
+        USAGE:
+            test [FLAGS] [OPTIONS]
+
+        FLAGS:
+                --flag_a     second flag
+                --flag_b     first flag
+            -h, --help       Prints help information
+            -V, --version    Prints version information
+
+        OPTIONS:
+                --option_a <option_a>    second option
+                --option_b <option_b>    first option
+    "));
+}
+
+#[test]
+fn derive_order() {
+    let app = App::new("test")
+        .setting(AppSettings::DeriveDisplayOrder)
+        .args(&[
+            Arg::with_name("flag_b").long("flag_b").help("first flag"),
+            Arg::with_name("option_b").long("option_b").takes_value(true).help("first option"),
+            Arg::with_name("flag_a").long("flag_a").help("second flag"),
+            Arg::with_name("option_a").long("option_a").takes_value(true).help("second option"),
+        ]);
+
+    assert_eq!(get_help(app, &["test"]), normalize("
+        test
+
+        USAGE:
+            test [FLAGS] [OPTIONS]
+
+        FLAGS:
+                --flag_b     first flag
+                --flag_a     second flag
+            -h, --help       Prints help information
+            -V, --version    Prints version information
+
+        OPTIONS:
+                --option_b <option_b>    first option
+                --option_a <option_a>    second option
+    "));
+}
+
+#[test]
+fn unified_help() {
+    let app = App::new("test")
+        .setting(AppSettings::UnifiedHelpMessage)
+        .args(&[
+            Arg::with_name("flag_b").long("flag_b").help("first flag"),
+            Arg::with_name("option_b").long("option_b").takes_value(true).help("first option"),
+            Arg::with_name("flag_a").long("flag_a").help("second flag"),
+            Arg::with_name("option_a").long("option_a").takes_value(true).help("second option"),
+        ]);
+
+    assert_eq!(get_help(app, &["test"]), normalize("
+        test
+
+        USAGE:
+            test [OPTIONS]
+
+        OPTIONS:
+                --flag_a     second flag
+                --flag_b     first flag
+            -h, --help       Prints help information
+                --option_a <option_a>    second option
+                --option_b <option_b>    first option
+            -V, --version    Prints version information
+    "));
+}
+
+#[test]
+fn unified_help_and_derive_order() {
+    let app = App::new("test")
+        .setting(AppSettings::DeriveDisplayOrder)
+        .setting(AppSettings::UnifiedHelpMessage)
+        .args(&[
+            Arg::with_name("flag_b").long("flag_b").help("first flag"),
+            Arg::with_name("option_b").long("option_b").takes_value(true).help("first option"),
+            Arg::with_name("flag_a").long("flag_a").help("second flag"),
+            Arg::with_name("option_a").long("option_a").takes_value(true).help("second option"),
+        ]);
+
+    assert_eq!(get_help(app, &["test"]), normalize("
+        test
+
+        USAGE:
+            test [OPTIONS]
+
+        OPTIONS:
+                --flag_b     first flag
+                --option_b <option_b>    first option
+                --flag_a     second flag
+                --option_a <option_a>    second option
+            -h, --help       Prints help information
+            -V, --version    Prints version information
+    "));
+}
+
+#[test]
+fn derive_order_subcommand_propagate() {
+    let app = App::new("test")
+        .global_setting(AppSettings::DeriveDisplayOrder)
+        .subcommand(SubCommand::with_name("sub")
+            .args(&[
+                Arg::with_name("flag_b").long("flag_b").help("first flag"),
+                Arg::with_name("option_b").long("option_b").takes_value(true).help("first option"),
+                Arg::with_name("flag_a").long("flag_a").help("second flag"),
+                Arg::with_name("option_a").long("option_a").takes_value(true).help("second option"),
+            ]));
+
+    assert_eq!(get_help(app, &["test", "sub"]), normalize("
+        test-sub
+
+        USAGE:
+            test sub [FLAGS] [OPTIONS]
+
+        FLAGS:
+                --flag_b     first flag
+                --flag_a     second flag
+            -h, --help       Prints help information
+            -V, --version    Prints version information
+
+        OPTIONS:
+                --option_b <option_b>    first option
+                --option_a <option_a>    second option
+    "));
+}
+
+#[test]
+fn unified_help_subcommand_propagate() {
+    let app = App::new("test")
+        .global_setting(AppSettings::UnifiedHelpMessage)
+        .subcommand(SubCommand::with_name("sub")
+            .args(&[
+                Arg::with_name("flag_b").long("flag_b").help("first flag"),
+                Arg::with_name("option_b").long("option_b").takes_value(true).help("first option"),
+                Arg::with_name("flag_a").long("flag_a").help("second flag"),
+                Arg::with_name("option_a").long("option_a").takes_value(true).help("second option"),
+            ]));
+
+    assert_eq!(get_help(app, &["test", "sub"]), normalize("
+        test-sub
+
+        USAGE:
+            test sub [OPTIONS]
+
+        OPTIONS:
+                --flag_a     second flag
+                --flag_b     first flag
+            -h, --help       Prints help information
+                --option_a <option_a>    second option
+                --option_b <option_b>    first option
+            -V, --version    Prints version information
+
+    "));
+}
+
+#[test]
+fn unified_help_and_derive_order_subcommand_propagate() {
+    let app = App::new("test")
+        .global_setting(AppSettings::DeriveDisplayOrder)
+        .global_setting(AppSettings::UnifiedHelpMessage)
+        .subcommand(SubCommand::with_name("sub")
+            .args(&[
+                Arg::with_name("flag_b").long("flag_b").help("first flag"),
+                Arg::with_name("option_b").long("option_b").takes_value(true).help("first option"),
+                Arg::with_name("flag_a").long("flag_a").help("second flag"),
+                Arg::with_name("option_a").long("option_a").takes_value(true).help("second option"),
+            ]));
+
+    assert_eq!(get_help(app, &["test", "sub"]), normalize("
+        test-sub
+
+        USAGE:
+            test sub [OPTIONS]
+
+        OPTIONS:
+                --flag_b     first flag
+                --option_b <option_b>    first option
+                --flag_a     second flag
+                --option_a <option_a>    second option
+            -h, --help       Prints help information
+            -V, --version    Prints version information
+
+    "));
+}
+
+#[test]
+fn unified_help_and_derive_order_subcommand_propagate_with_explicit_display_order() {
+    let app = App::new("test")
+        .global_setting(AppSettings::DeriveDisplayOrder)
+        .global_setting(AppSettings::UnifiedHelpMessage)
+        .subcommand(SubCommand::with_name("sub")
+            .args(&[
+                Arg::with_name("flag_b").long("flag_b").help("first flag"),
+                Arg::with_name("option_b").long("option_b").takes_value(true).help("first option"),
+                Arg::with_name("flag_a").long("flag_a").help("second flag").display_order(0),
+                Arg::with_name("option_a").long("option_a").takes_value(true).help("second option"),
+            ]));
+
+    assert_eq!(get_help(app, &["test", "sub"]), normalize("
+        test-sub
+
+        USAGE:
+            test sub [OPTIONS]
+
+        OPTIONS:
+                --flag_a     second flag
+                --flag_b     first flag
+                --option_b <option_b>    first option
+                --option_a <option_a>    second option
+            -h, --help       Prints help information
+            -V, --version    Prints version information
+
+    "));
+}