ENH: store model name in tree.params, fixes #354

Author: YapengLang

src/piqtree/iqtree/_tree.py

@@ -77,6 +77,7 @@ def _process_tree_yaml(
     _rename_iq_tree(tree, names)
 
     tree.name_unnamed_nodes()
+    tree.params["model"] = str(model)
 
     return tree
 

tests/test_iqtree/test_build_tree.py

@@ -34,6 +34,7 @@ def check_build_tree_model(
     assert expected.same_topology(got.unrooted())
     # Check if branch lengths exist
     assert all(v.length is not None for v in got.get_edge_vector(include_root=False))
+    assert got.params["model"] == str(model)
 
 
 def check_build_tree(

tests/test_iqtree/test_fit_tree.py

@@ -11,6 +11,11 @@
 from piqtree.model import Model, StandardDnaModel
 
 
+def check_model_name(got: PhyloNode, expected: str) -> None:
+    got_model = cast("str", got.params.get("model"))
+    assert got_model == expected
+
+
 def check_likelihood(got: PhyloNode, expected: model_result) -> None:
     assert got.params["lnL"] == pytest.approx(expected.lnL)
 
@@ -95,6 +100,7 @@ def test_fit_tree(
     check_motif_probs(got, expected.tree)
     check_rate_parameters(got, expected.tree)
     check_branch_lengths(got, expected.tree)
+    check_model_name(got, str(model))
 
 
 @pytest.mark.parametrize(