From 03abd47f4945a8fdb9ffd0af76288493cd59afe1 Mon Sep 17 00:00:00 2001
From: AbdealiJK <abdealikothari@gmail.com>
Date: Sun, 4 Dec 2016 13:15:09 +0530
Subject: [PATCH] tests/cpp: Add tests for Metric RMSE

---
 tests/cpp/helpers.cc                        | 11 +++++++++++
 tests/cpp/helpers.h                         |  7 +++++++
 tests/cpp/metric/test_elementwise_metric.cc | 14 ++++++++++++++
 3 files changed, 32 insertions(+)
 create mode 100644 tests/cpp/metric/test_elementwise_metric.cc

diff --git a/tests/cpp/helpers.cc b/tests/cpp/helpers.cc
index 31349b3ab..a6dee1133 100644
--- a/tests/cpp/helpers.cc
+++ b/tests/cpp/helpers.cc
@@ -49,3 +49,14 @@ void CheckObjFunction(xgboost::ObjFunction * obj,
       << " weight=" << weights[i];
   }
 }
+
+xgboost::bst_float GetMetricEval(xgboost::Metric * metric,
+                                 std::vector<xgboost::bst_float> preds,
+                                 std::vector<xgboost::bst_float> labels,
+                                 std::vector<xgboost::bst_float> weights) {
+  xgboost::MetaInfo info;
+  info.num_row = labels.size();
+  info.labels = labels;
+  info.weights = weights;
+  return metric->Eval(preds, info, false);
+}
diff --git a/tests/cpp/helpers.h b/tests/cpp/helpers.h
index 41945e3aa..94bef0771 100644
--- a/tests/cpp/helpers.h
+++ b/tests/cpp/helpers.h
@@ -13,6 +13,7 @@
 
 #include <xgboost/base.h>
 #include <xgboost/objective.h>
+#include <xgboost/metric.h>
 
 std::string TempFileName();
 
@@ -29,4 +30,10 @@ void CheckObjFunction(xgboost::ObjFunction * obj,
                       std::vector<xgboost::bst_float> out_grad,
                       std::vector<xgboost::bst_float> out_hess);
 
+xgboost::bst_float GetMetricEval(
+  xgboost::Metric * metric,
+  std::vector<xgboost::bst_float> preds,
+  std::vector<xgboost::bst_float> labels,
+  std::vector<xgboost::bst_float> weights = std::vector<xgboost::bst_float> ());
+
 #endif
diff --git a/tests/cpp/metric/test_elementwise_metric.cc b/tests/cpp/metric/test_elementwise_metric.cc
new file mode 100644
index 000000000..8aba13e6a
--- /dev/null
+++ b/tests/cpp/metric/test_elementwise_metric.cc
@@ -0,0 +1,14 @@
+// Copyright by Contributors
+#include <xgboost/metric.h>
+
+#include "../helpers.h"
+
+TEST(Metric, RMSE) {
+  xgboost::Metric * metric = xgboost::Metric::Create("rmse");
+  ASSERT_STREQ(metric->Name(), "rmse");
+  EXPECT_NEAR(GetMetricEval(metric, {0, 1}, {0, 1}), 0, 1e-10);
+  EXPECT_NEAR(GetMetricEval(metric,
+                            {0.1, 0.9, 0.1, 0.9},
+                            {  0,   0,   1,   1}),
+              0.6403, 0.001);
+}