From e94d1c5537bb868f49d6d9f33eb51d754788c737 Mon Sep 17 00:00:00 2001
From: Axel Kohlmeyer <akohlmey@gmail.com>
Date: Sun, 9 Aug 2020 01:01:35 -0400
Subject: [PATCH] add function to query whether ErrorStats class has data

---
 unittest/force-styles/error_stats.h        | 1 +
 unittest/force-styles/test_error_stats.cpp | 2 ++
 2 files changed, 3 insertions(+)

diff --git a/unittest/force-styles/error_stats.h b/unittest/force-styles/error_stats.h
index 664a987907..b9c44e4027 100644
--- a/unittest/force-styles/error_stats.h
+++ b/unittest/force-styles/error_stats.h
@@ -29,6 +29,7 @@ public:
     double dev() const;
     double max() const { return maxerr; }
     double idx() const { return maxidx; }
+    bool has_data() const { return num > 0; }
 
 private:
     double sum, sumsq, maxerr;
diff --git a/unittest/force-styles/test_error_stats.cpp b/unittest/force-styles/test_error_stats.cpp
index 42c185db83..0873757acd 100644
--- a/unittest/force-styles/test_error_stats.cpp
+++ b/unittest/force-styles/test_error_stats.cpp
@@ -29,12 +29,14 @@ TEST(ErrorStats, test)
     ASSERT_EQ(out.str(), "Average:  5.800e-01 StdDev:  7.305e-01 MaxErr:  2.000e+00 @ item: 3.0");
 
     stats.reset();
+    ASSERT_EQ(stats.has_data(), false);
     ASSERT_DOUBLE_EQ(stats.avg(), 0.0);
     ASSERT_DOUBLE_EQ(stats.dev(), 0.0);
     ASSERT_DOUBLE_EQ(stats.max(), 0.0);
     ASSERT_EQ(stats.idx(), -1);
 
     stats.add(1.0);
+    ASSERT_EQ(stats.has_data(), true);
     ASSERT_DOUBLE_EQ(stats.avg(), 1.0);
     ASSERT_DOUBLE_EQ(stats.dev(), 0.0);
     ASSERT_DOUBLE_EQ(stats.max(), 1.0);