add unittest for ErrorStats class

unittest/force-styles/CMakeLists.txt

@@ -15,6 +15,11 @@ else()
   target_link_libraries(style_tests PUBLIC mpi_stubs)
 endif()
 
+# unit test for error stats class
+add_executable(test_error_stats test_error_stats.cpp)
+target_link_libraries(test_error_stats PRIVATE GTest::GTestMain GTest::GTest)
+add_test(NAME ErrorStats COMMAND test_error_stats)
+
 # pair style tester
 add_executable(pair_style pair_style.cpp)
 target_link_libraries(pair_style PRIVATE lammps style_tests)

unittest/force-styles/test_error_stats.cpp

@@ -0,0 +1,41 @@
+
+#include "gtest/gtest.h"
+#include <sstream>
+#include <string>
+
+// include the implementation since ErrorStats is a standalone class
+// this way we don't have to link against the style_tests and lammps libs
+
+#include "error_stats.cpp"
+
+TEST(ErrorStats, test)
+{
+    ErrorStats stats;
+
+    stats.add(0.5);
+    stats.add(0.1);
+    stats.add(2.0);
+    stats.add(0.3);
+    stats.add(0);
+
+    ASSERT_DOUBLE_EQ(stats.avg(), 0.58);
+    ASSERT_DOUBLE_EQ(stats.dev(), 0.73047929470998685);
+    ASSERT_DOUBLE_EQ(stats.max(), 2.0);
+    ASSERT_EQ(stats.idx(), 3);
+
+    std::stringstream out;
+    out << stats;
+    ASSERT_EQ(out.str(), " Average: 5.800e-01 StdDev: 7.305e-01 MaxErr: 2.000e+00 @ item: 3");
+
+    stats.reset();
+    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_DOUBLE_EQ(stats.avg(), 1.0);
+    ASSERT_DOUBLE_EQ(stats.dev(), 0.0);
+    ASSERT_DOUBLE_EQ(stats.max(), 1.0);
+    ASSERT_EQ(stats.idx(), 1);
+}