[T/MPL] Test the ExponentialProperty.

Tests/MaterialLib/TestMPLExponentialProperty.cpp

+/**
+ * \file
+ *
+ * \copyright
+ * Copyright (c) 2012-2019, OpenGeoSys Community (http://www.opengeosys.org)
+ *            Distributed under a Modified BSD License.
+ *              See accompanying file LICENSE.txt or
+ *              http://www.opengeosys.org/project/license
+ *
+ */
+#include <cmath>
+
+#include <gtest/gtest.h>
+
+#include "MaterialLib/MPL/Properties/ExponentialProperty.h"
+
+TEST(MaterialPropertyLib, ExponentialProperty)
+{
+    double const y_ref = 1e-3;
+    double const reference_condition = 20.0;
+    double const factor = 1 / 75.0;
+    MaterialPropertyLib::ExponentData const exp_data{
+        MaterialPropertyLib::Variable::temperature, reference_condition, factor};
+    MaterialPropertyLib::ExponentialProperty exp_property{y_ref, exp_data};
+
+    MaterialPropertyLib::VariableArray variable_array;
+    variable_array[static_cast<int>(
+        MaterialPropertyLib::Variable::temperature)] = 20;
+    ASSERT_NEAR(
+        boost::get<double>(exp_property.value(variable_array)),
+        y_ref * (std::exp(-factor *
+                          (boost::get<double>(variable_array[static_cast<int>(
+                               MaterialPropertyLib::Variable::temperature)]) -
+                           reference_condition))),
+        1.e-10);
+    ASSERT_EQ(
+        boost::get<double>(exp_property.dValue(
+            variable_array, MaterialPropertyLib::Variable::phase_pressure)),
+        0.0);
+    ASSERT_NEAR(
+        boost::get<double>(exp_property.dValue(
+            variable_array, MaterialPropertyLib::Variable::temperature)),
+        -y_ref * factor *
+            std::exp(-factor *
+                     (boost::get<double>(variable_array[static_cast<int>(
+                          MaterialPropertyLib::Variable::temperature)]) -
+                      reference_condition)),
+        1.e-16);
+    ASSERT_NEAR(
+        boost::get<double>(
+            exp_property.d2Value(variable_array,
+                                 MaterialPropertyLib::Variable::temperature,
+                                 MaterialPropertyLib::Variable::temperature)),
+        y_ref * std::pow(factor, 2) *
+            std::exp(-factor *
+                     (boost::get<double>(variable_array[static_cast<int>(
+                          MaterialPropertyLib::Variable::temperature)]) -
+                      reference_condition)),
+        1.e-16);
+}
+