import test infrastructure for c, c++ and python library usage

unittest/c-library/library-properties.cpp

@@ -0,0 +1,45 @@
+// unit tests for checking and changing simulation properties through the library interface
+
+#include "library.h"
+#include "lammps.h"
+#include <string>
+
+#include "gtest/gtest.h"
+
+const char *demo_input[] = {
+      "region       box block 0 $x 0 2 0 2",
+      "create_box 1 box",
+      "create_atoms 1 single 1.0 1.0 ${zpos}" };
+const char *cont_input[] = {
+    "create_atoms 1 single &",
+    "0.2 0.1 0.1" };
+
+class LAMMPS_properties : public ::testing::Test
+{
+protected:
+    void *lmp;
+    LAMMPS_properties() {};
+    ~LAMMPS_properties() override {};
+
+    void SetUp() override {
+        const char *args[] = {"LAMMPS_test", "-log", "none",
+                              "-echo", "screen", "-nocite" };
+        char **argv = (char **)args;
+        int argc = sizeof(args)/sizeof(char *);
+
+        ::testing::internal::CaptureStdout();
+        lmp = lammps_open_no_mpi(argc, argv, NULL);
+        std::string output = ::testing::internal::GetCapturedStdout();
+        EXPECT_STREQ(output.substr(0,8).c_str(), "LAMMPS (");
+    }
+    void TearDown() override {
+        ::testing::internal::CaptureStdout();
+        lammps_close(lmp);
+        std::string output = ::testing::internal::GetCapturedStdout();
+        EXPECT_STREQ(output.substr(0,16).c_str(), "Total wall time:");
+        lmp = nullptr;
+    }
+};
+
+TEST_F(LAMMPS_properties, box) {
+};