cl/427812386 Create a cc_binary to update output files (#37638)

validator/cpp/engine/BUILD

@@ -322,6 +322,16 @@ cc_library(
     ],
 )
 
+cc_binary(
+    name = "update-tests",
+    srcs = ["update-tests.cc"],
+    copts = ["-std=c++17"],
+    deps = [
+        ":testing-utils",
+        ":validator",
+    ],
+)
+
 cc_test(
     name = "validator_test",
     srcs = ["validator_test.cc"],

validator/cpp/engine/update-tests.cc

@@ -0,0 +1,43 @@
+// A binary which runs the validator over golden test input files and overwrites
+// all output files. It is useful to update a bunch of test and then inspect
+// the diff.
+
+#include <fstream>
+
+#include "absl/strings/str_replace.h"
+#include "cpp/engine/testing-utils.h"
+#include "cpp/engine/validator.h"
+
+namespace amp::validator {
+namespace {
+
+void UpdateTests() {
+  for (const auto& entry : testing::TestCases()) {
+    const testing::TestCase& test_case = entry.second;
+    ValidationResult result =
+        Validate(test_case.input_content, test_case.html_format);
+    std::string output_content = testing::RenderInlineResult(
+        test_case.name, test_case.input_content, result);
+    const std::string output_filename = absl::StrReplaceAll(
+        test_case.output_file,
+        {{"external/validator/testdata/", "validator/testdata/"},
+         {"external/amphtml-extensions/", "extensions/"}});
+    if (output_content == test_case.output_content) {
+      std::cout << "Unchanged validation: " << output_filename << std::endl;
+    } else {
+      std::cout << "Updating validation: " << output_filename << std::endl;
+      std::ofstream output_stream;
+      output_stream.open(output_filename);
+      output_stream << output_content;
+      output_stream.close();
+    }
+  }
+}
+
+}  // namespace
+}  // namespace amp::validator
+
+int main(int argc, char* argv[]) {
+  amp::validator::UpdateTests();
+  return 0;
+}