From 12cd2132ff428e81c5c5d18b3ac76cfd39149f74 Mon Sep 17 00:00:00 2001
From: Max Brunsfeld <maxbrunsfeld@gmail.com>
Date: Wed, 4 Jan 2017 21:23:04 -0800
Subject: [PATCH] Add test for retrieving last external token state in a Tree

---
 spec/runtime/tree_spec.cc | 35 +++++++++++++++++++++++++++++++++++
 src/runtime/tree.c        |  2 ++
 2 files changed, 37 insertions(+)

diff --git a/spec/runtime/tree_spec.cc b/spec/runtime/tree_spec.cc
index b67cd0a8..bdc8145f 100644
--- a/spec/runtime/tree_spec.cc
+++ b/spec/runtime/tree_spec.cc
@@ -30,6 +30,9 @@ describe("Tree", []() {
     symbol4,
     symbol5,
     symbol6,
+    symbol7,
+    symbol8,
+    symbol9,
   };
 
   TSSymbolMetadata visible = {true, true, false, true};
@@ -399,6 +402,38 @@ describe("Tree", []() {
       ts_tree_release(different_parent);
     });
   });
+
+  describe("last_external_token_state", [&]() {
+    Length padding = {1, 1, {0, 1}};
+    Length size = {2, 2, {0, 2}};
+
+    auto make_external = [](Tree *tree) {
+      tree->has_external_tokens = true;
+      tree->has_external_token_state = true;
+      return tree;
+    };
+
+    it("returns the last serialized external token state in the given tree", [&]() {
+      Tree *tree1, *tree2, *tree3, *tree4, *tree5, *tree6, *tree7, *tree8, *tree9;
+
+      tree1 = ts_tree_make_node(symbol1, 2, tree_array({
+        (tree2 = ts_tree_make_node(symbol2, 3, tree_array({
+          (tree3 = make_external(ts_tree_make_leaf(symbol3, padding, size, visible))),
+          (tree4 = ts_tree_make_leaf(symbol4, padding, size, visible)),
+          (tree5 = ts_tree_make_leaf(symbol5, padding, size, visible)),
+        }), visible)),
+        (tree6 = ts_tree_make_node(symbol6, 2, tree_array({
+          (tree7 = ts_tree_make_node(symbol7, 1, tree_array({
+            (tree8 = ts_tree_make_leaf(symbol8, padding, size, visible)),
+          }), visible)),
+          (tree9 = ts_tree_make_leaf(symbol9, padding, size, visible)),
+        }), visible)),
+      }), visible);
+
+      auto state = ts_tree_last_external_token_state(tree1);
+      AssertThat(state, Equals(&tree3->external_token_state));
+    });
+  });
 });
 
 END_TEST
diff --git a/src/runtime/tree.c b/src/runtime/tree.c
index ebcca441..858ad90e 100644
--- a/src/runtime/tree.c
+++ b/src/runtime/tree.c
@@ -386,6 +386,8 @@ const TSExternalTokenState *ts_tree_last_external_token_state(const Tree *tree)
       if (child->has_external_token_state) {
         tree = child;
         break;
+      } else if (child->has_external_tokens) {
+        return NULL;
       }
     }
   }