Added a new unit test TestMetrics.cpp

Signed-off-by: Jaehyun Kim <jhkim@precisioninno.com>

Author: jhkim-pii

src/utl/test/cpp/CMakeLists.txt

@@ -18,3 +18,16 @@ gtest_discover_tests(TestCFileUtils
 add_dependencies(build_and_test
   TestCFileUtils
 )
+
+
+add_executable(TestMetrics TestMetrics.cpp)
+
+target_link_libraries(TestMetrics ${TEST_LIBS})
+
+gtest_discover_tests(TestMetrics
+  WORKING_DIRECTORY ${CMAKE_CURRENT_SOURCE_DIR}
+)
+
+add_dependencies(build_and_test
+  TestMetrics
+)

src/utl/test/cpp/TestMetrics.cpp

@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: BSD-3-Clause
+// Copyright (c) 2024, The OpenROAD Authors
+
+#include <cstdio>
+#include <fstream>
+#include <iterator>
+#include <string>
+
+#include "gtest/gtest.h"
+#include "utl/Logger.h"
+
+namespace utl {
+
+TEST(Utl, WarningMetrics)
+{
+  // ARRANGE
+  std::string metrics_filename = "test_metrics_warning_metrics.rpt";
+  // The logger must be scoped to trigger the destructor which writes the
+  // metrics
+  {
+    utl::Logger logger;
+    logger.addMetricsSink(metrics_filename.c_str());
+
+    // ACTION
+    for (int i = 0; i < 10; i++) {
+      logger.warn(utl::UTL, 20, "Test warning UTL-20.");
+    }
+    logger.warn(utl::UTL, 21, "Another test warning UTL-21.");
+  }
+
+  // ASSERT
+  std::ifstream metrics_file(metrics_filename);
+  ASSERT_TRUE(metrics_file.good());
+  std::string content((std::istreambuf_iterator<char>(metrics_file)),
+                      (std::istreambuf_iterator<char>()));
+
+  // The output is a JSON string, which may be multi-line.
+  // For simplicity, we'll just check for substrings.
+  EXPECT_NE(content.find("\"flow__warnings__count\": 11"), std::string::npos);
+  EXPECT_NE(content.find("\"flow__errors__count\": 0"), std::string::npos);
+  EXPECT_NE(content.find("\"flow__warnings__count:UTL-20\": 10"),
+            std::string::npos);
+  EXPECT_NE(content.find("\"flow__warnings__count:UTL-21\": 1"),
+            std::string::npos);
+  EXPECT_NE(content.find("\"flow__warnings__type_count\": 2"),
+            std::string::npos);
+
+  // Clean up
+  std::remove(metrics_filename.c_str());
+}
+
+}  // namespace utl