Factor EXPECT_SAME_FILE into separate module

I want to use EXPECT_SAME_FILE from multiple test files. Move this macro
into its own file.

Author: strager

test/CMakeLists.txt

@@ -14,6 +14,7 @@ quick_lint_js_add_executable(
   quick-lint-js/array.h
   quick-lint-js/characters.h
   quick-lint-js/error-matcher.h
+  quick-lint-js/file-matcher.h
   quick-lint-js/gtest.h
   quick-lint-js/parse-json.h
   quick-lint-js/parse-support.h

test/quick-lint-js/file-matcher.h

@@ -0,0 +1,42 @@
+// Copyright (C) 2020  Matthew Glazar
+// See end of file for extended copyright information.
+
+#ifndef QUICK_LINT_JS_FILE_MATCHER_H
+#define QUICK_LINT_JS_FILE_MATCHER_H
+
+#include <gtest/gtest.h>
+#include <quick-lint-js/file.h>
+
+#define EXPECT_SAME_FILE(path_a, path_b)                           \
+  do {                                                             \
+    ::quick_lint_js::canonical_path_result path_a_canonical_ =     \
+        ::quick_lint_js::canonicalize_path((path_a));              \
+    ASSERT_TRUE(path_a_canonical_.ok())                            \
+        << std::move(path_a_canonical_).error();                   \
+    ::quick_lint_js::canonical_path_result path_b_canonical_ =     \
+        ::quick_lint_js::canonicalize_path((path_b));              \
+    ASSERT_TRUE(path_b_canonical_.ok())                            \
+        << std::move(path_b_canonical_).error();                   \
+    EXPECT_EQ(path_a_canonical_.path(), path_b_canonical_.path())  \
+        << (path_a) << " should be the same file as " << (path_b); \
+  } while (false)
+
+#endif
+
+// quick-lint-js finds bugs in JavaScript programs.
+// Copyright (C) 2020  Matthew Glazar
+//
+// This file is part of quick-lint-js.
+//
+// quick-lint-js is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// quick-lint-js is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with quick-lint-js.  If not, see <https://www.gnu.org/licenses/>.

test/test-configuration-loader.cpp

@@ -8,6 +8,7 @@
 #include <gtest/gtest.h>
 #include <quick-lint-js/configuration-loader.h>
 #include <quick-lint-js/configuration.h>
+#include <quick-lint-js/file-matcher.h>
 #include <quick-lint-js/file.h>
 #include <quick-lint-js/options.h>
 #include <quick-lint-js/temporary-directory.h>
@@ -30,18 +31,6 @@ QLJS_WARNING_IGNORE_GCC("-Wmissing-field-initializers")
     EXPECT_FALSE((config).globals().find(u8"variableDoesNotExist"sv)); \
   } while (false)
 
-#define EXPECT_SAME_FILE(path_a, path_b)                                   \
-  do {                                                                     \
-    canonical_path_result path_a_canonical_ = canonicalize_path((path_a)); \
-    ASSERT_TRUE(path_a_canonical_.ok())                                    \
-        << std::move(path_a_canonical_).error();                           \
-    canonical_path_result path_b_canonical_ = canonicalize_path((path_b)); \
-    ASSERT_TRUE(path_b_canonical_.ok())                                    \
-        << std::move(path_b_canonical_).error();                           \
-    EXPECT_EQ(path_a_canonical_.path(), path_b_canonical_.path())          \
-        << (path_a) << " should be the same file as " << (path_b);         \
-  } while (false)
-
 using ::testing::AnyOf;
 using ::testing::HasSubstr;
 using namespace std::literals::string_view_literals;