test: arg groups from enum

Author: ysndr

tests/derive/groups.rs

@@ -239,3 +239,70 @@ For more information, try '--help'.
 ";
     assert_output::<Opt>("test", OUTPUT, true);
 }
+
+#[test]
+fn enum_groups_1() {
+    #[derive(Parser, Debug, PartialEq, Eq)]
+    struct Opt {
+        #[command(flatten)]
+        source: Source,
+    }
+
+    #[derive(clap::Args, Clone, Debug, PartialEq, Eq)]
+    enum Source {
+        A {
+            #[arg(short)]
+            a: bool,
+            #[arg(long)]
+            aa: bool,
+            #[arg(long)]
+            aaa: bool,
+        },
+        B {
+            #[arg(short)]
+            b: bool,
+            #[arg(long)]
+            bb: bool,
+            #[arg(long)]
+            bbb: bool,
+        },
+    }
+
+    assert_eq!(
+        Opt {
+            source: Source::A {
+                a: true,
+                aa: false,
+                aaa: false
+            }
+        },
+        Opt::try_parse_from(["test", "-a"]).unwrap()
+    );
+    assert_eq!(
+        Opt {
+            source: Source::A {
+                a: true,
+                aa: false,
+                aaa: true
+            }
+        },
+        Opt::try_parse_from(["test", "-a", "--aaa"]).unwrap()
+    );
+    assert_eq!(
+        Opt {
+            source: Source::B {
+                b: true,
+                bb: false,
+                bbb: false
+            }
+        },
+        Opt::try_parse_from(["test", "-b"]).unwrap()
+    );
+
+    assert_eq!(
+        clap::error::ErrorKind::ArgumentConflict,
+        Opt::try_parse_from(["test", "-b", "-a"]).unwrap_err().kind(),
+    );
+
+    // assert_eq!(       )
+}