[lite] Add unit test for stderr_reporter.

PiperOrigin-RevId: 337112639
Change-Id: I0cc00cd9ead8a4ca81f32a0153398aad3506eb30

tensorflow/lite/BUILD

@@ -628,6 +628,15 @@ cc_test(
     ],
 )
 
+cc_test(
+    name = "stderr_reporter_test",
+    srcs = ["stderr_reporter_test.cc"],
+    deps = [
+        ":stderr_reporter",
+        "@com_google_googletest//:gtest_main",
+    ],
+)
+
 cc_library(
     name = "util",
     srcs = ["util.cc"],

tensorflow/lite/stderr_reporter_test.cc

@@ -0,0 +1,49 @@
+/* Copyright 2020 The TensorFlow Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+==============================================================================*/
+#include "tensorflow/lite/stderr_reporter.h"
+
+#include <cstdio>
+
+#include <gtest/gtest.h>
+
+namespace tflite {
+
+namespace {
+
+void CheckWritesToStderr(ErrorReporter *error_reporter) {
+#ifndef TF_LITE_STRIP_ERROR_STRINGS
+  testing::internal::CaptureStderr();
+#endif
+
+  // Run the code under test.
+  TF_LITE_REPORT_ERROR(error_reporter, "Test: %d", 42);
+
+#ifndef TF_LITE_STRIP_ERROR_STRINGS
+  EXPECT_EQ("ERROR: Test: 42\n", testing::internal::GetCapturedStderr());
+#endif
+}
+
+TEST(StderrReporterTest, DefaultErrorReporter_WritesToStderr) {
+  CheckWritesToStderr(DefaultErrorReporter());
+}
+
+TEST(StderrReporterTest, StderrReporter_WritesToStderr) {
+  StderrReporter stderr_reporter;
+  CheckWritesToStderr(&stderr_reporter);
+}
+
+}  // namespace
+
+}  // namespace tflite