Add a test

tests/groups.rs

@@ -18,9 +18,27 @@ USAGE:
 
 For more information try --help";
 
+#[allow(unused)]
+static REQ_GROUP_CONFLICT_REV: &str = "error: The argument '--delete' cannot be used with '<base>'
+
+USAGE:
+    clap-test <base|--delete>
+
+For more information try --help";
+
+static REQ_GROUP_CONFLICT_ONLY_OPTIONS: &str =
+    "error: Found argument '--all' which wasn't expected, or isn't valid in this context
+
+If you tried to supply `--all` as a PATTERN use `-- --all`
+
+USAGE:
+    clap-test <-a|--delete>
+
+For more information try --help";
+
 // FIXME: This message has regressed after https://github.com/clap-rs/clap/pull/1856
 //        Need to roll back somehow.
-static REQ_GROUP_CONFLICT_REV: &str =
+static REQ_GROUP_CONFLICT_REV_DEGRADED: &str =
     "error: Found argument 'base' which wasn't expected, or isn't valid in this context
 
 If you tried to supply `base` as a PATTERN use `-- base`
@@ -213,7 +231,28 @@ fn req_group_with_conflict_usage_string() {
     assert!(utils::compare_output2(
         app,
         "clap-test --delete base",
-        REQ_GROUP_CONFLICT_REV,
+        REQ_GROUP_CONFLICT_REV_DEGRADED,
+        REQ_GROUP_CONFLICT_USAGE,
+        true
+    ));
+}
+
+#[test]
+fn req_group_with_conflict_usage_string_only_options() {
+    let app = App::new("req_group")
+        .arg(Arg::from("<all> -a, -all 'All'").conflicts_with("delete"))
+        .arg(Arg::from(
+            "<delete> -d, --delete 'Remove the base commit information'",
+        ))
+        .group(
+            ArgGroup::with_name("all_or_delete")
+                .args(&["all", "delete"])
+                .required(true),
+        );
+    assert!(utils::compare_output2(
+        app,
+        "clap-test --delete --all",
+        REQ_GROUP_CONFLICT_ONLY_OPTIONS,
         REQ_GROUP_CONFLICT_USAGE,
         true
     ));