From b9dc92c36bffe26496b80ba7d7e8f2638345e6f5 Mon Sep 17 00:00:00 2001
From: Max Brunsfeld <maxbrunsfeld@gmail.com>
Date: Mon, 25 May 2015 20:44:23 -0700
Subject: [PATCH] Add EqualsTree matcher

---
 spec/runtime/helpers/tree_helpers.cc | 12 ++++++++++++
 spec/runtime/helpers/tree_helpers.h  | 10 ++++++++++
 spec/runtime/parse_stack_spec.cc     | 26 +++++++++-----------------
 3 files changed, 31 insertions(+), 17 deletions(-)

diff --git a/spec/runtime/helpers/tree_helpers.cc b/spec/runtime/helpers/tree_helpers.cc
index 80d51ab6..2e4c7f98 100644
--- a/spec/runtime/helpers/tree_helpers.cc
+++ b/spec/runtime/helpers/tree_helpers.cc
@@ -6,3 +6,15 @@ TSTree ** tree_array(std::vector<TSTree *> trees) {
       result[i] = trees[i];
   return result;
 }
+
+EqualsTree::EqualsTree(const TSTree *expected, const char **symbol_names)
+  : expected(expected), symbol_names(symbol_names) {}
+
+bool EqualsTree::Matches(const TSTree *actual) const {
+  return ts_tree_eq(actual, expected);
+}
+
+std::ostream &operator<<(std::ostream &stream, const EqualsTree &matcher) {
+  stream << std::string("equals tree: ") << std::string(ts_tree_string(matcher.expected, matcher.symbol_names));
+  return stream;
+}
diff --git a/spec/runtime/helpers/tree_helpers.h b/spec/runtime/helpers/tree_helpers.h
index fc0e5773..e024c666 100644
--- a/spec/runtime/helpers/tree_helpers.h
+++ b/spec/runtime/helpers/tree_helpers.h
@@ -3,7 +3,17 @@
 
 #include "runtime/tree.h"
 #include <vector>
+#include <string>
 
 TSTree ** tree_array(std::vector<TSTree *> trees);
 
+struct EqualsTree {
+  EqualsTree(const TSTree *expected, const char **symbol_names);
+  bool Matches(const TSTree *actual) const;
+  const TSTree *expected;
+  const char **symbol_names;
+};
+
+std::ostream &operator<<(std::ostream &stream, const EqualsTree &matcher);
+
 #endif  // HELPERS_TREE_HELPERS_H_
diff --git a/spec/runtime/parse_stack_spec.cc b/spec/runtime/parse_stack_spec.cc
index 834a6030..dad6e61d 100644
--- a/spec/runtime/parse_stack_spec.cc
+++ b/spec/runtime/parse_stack_spec.cc
@@ -70,12 +70,9 @@ describe("ParseStack", [&]() {
 
       ParseStackNode *head = ts_parse_stack_head(stack, 0);
       AssertThat(head->state, Equals(103));
-      AssertThat(
-        ts_tree_eq(
-          head->tree,
-          ts_tree_make_node(symbol4, 2, tree_array({ trees[1], trees[2] }), false)
-        ),
-        IsTrue());
+      AssertThat(head->tree, Fulfills(EqualsTree(
+        ts_tree_make_node(symbol4, 2, tree_array({ trees[1], trees[2] }), false),
+        names)));
       AssertThat(head->successor_count, Equals(1));
 
       head = head->successors[0];
@@ -94,12 +91,9 @@ describe("ParseStack", [&]() {
 
         ParseStackNode *head = ts_parse_stack_head(stack, 0);
         AssertThat(head->state, Equals(103));
-        AssertThat(
-          ts_tree_eq(
-            head->tree,
-            ts_tree_make_node(symbol4, 3, tree_array({ trees[0], trees[1], trees[2] }), false)
-          ),
-          IsTrue());
+        AssertThat(head->tree, Fulfills(EqualsTree(
+          ts_tree_make_node(symbol4, 3, tree_array({ trees[0], trees[1], trees[2] }), false),
+          names)));
         AssertThat(head->successor_count, Equals(1));
 
         head = head->successors[0];
@@ -198,11 +192,9 @@ describe("ParseStack", [&]() {
       AssertThat(ts_parse_stack_head_count(stack), Equals(1));
       ParseStackNode *head = ts_parse_stack_head(stack, 0);
       AssertThat(head->state, Equals(stateG));
-      AssertThat(
-        ts_tree_eq(
-          head->tree,
-          ts_tree_make_node(symbol5, 1, tree_array({ trees[4] }), false)),
-        IsTrue());
+      AssertThat(head->tree, Fulfills(EqualsTree(
+        ts_tree_make_node(symbol5, 1, tree_array({ trees[4] }), false),
+        names)));
       AssertThat(head->successor_count, Equals(2));
     });
   });