added group tests

tests/group/test.typ

@@ -0,0 +1,51 @@
+#set page(width: auto, height: auto)
+#import "/src/lib.typ": *
+
+#diagram({
+  _seq("Alice", "Bob", comment: "Authentication Request")
+
+  _alt(
+    "successful case", {
+      _seq("Bob", "Alice", comment: "Authentication Accepted")
+    },
+    "some kind of failure", {
+      _seq("Bob", "Alice", comment: "Authentication Failure")
+
+      _grp("My own label", desc: "My own label2", {
+        _seq("Alice", "Log", comment: "Log attack start")
+        _loop("1000 times", {
+          _seq("Alice", "Bob", comment: "DNS Attack")
+        })
+        _seq("Alice", "Log", comment: "Log attack end")
+      })
+    },
+    "Another type of failure", {
+      _seq("Bob", "Alice", comment: "Please repeat")
+    }
+  )
+})
+
+#pagebreak()
+
+#diagram({
+  _par("a", display-name: box(width: 1.5em, height: .5em), show-bottom: false)
+  _par("b", display-name: box(width: 1.5em, height: .5em), show-bottom: false)
+  _col("a", "b", width: 2cm)
+  _loop("a<1", min: 1, {
+    _seq("a", "b", end-tip: ">>")
+    _seq("b", "a", end-tip: ">>")
+  })
+  _seq("a", "b", end-tip: ">>")
+})
+
+#pagebreak()
+
+#diagram({
+  _par("A")
+  _par("B")
+  _col("A", "B", width: 3cm)
+  _seq("A", "B", enable-dst: true)
+  _alt([desc], {
+    _ret()
+  })
+})