add tests for lammps configuration introspection via library interface

unittest/c-library/test_library_config.cpp

@@ -0,0 +1,61 @@
+// unit tests for checking LAMMPS configuration settings  through the library interface
+
+#include "library.h"
+#include "lammps.h"
+#include <string>
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+
+#include "test_main.h"
+
+#define STRINGIFY(val) XSTR(val)
+#define XSTR(val) #val
+
+using ::testing::HasSubstr;
+using ::testing::StartsWith;
+
+class LAMMPS_config : public ::testing::Test {
+protected:
+    void *lmp;
+    std::string INPUT_DIR = STRINGIFY(TEST_INPUT_FOLDER);
+
+    LAMMPS_config(){};
+    ~LAMMPS_config() override{};
+
+    void SetUp() override
+    {
+        const char *args[] = {"LAMMPS_test", "-log",      "none",
+                              "-echo",       "screen",    "-nocite",
+                              "-var",        "input_dir", STRINGIFY(TEST_INPUT_FOLDER)};
+
+        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();
+        if (verbose) std::cout << output;
+        EXPECT_THAT(output, StartsWith("LAMMPS ("));
+    }
+    void TearDown() override
+    {
+        ::testing::internal::CaptureStdout();
+        lammps_close(lmp);
+        std::string output = ::testing::internal::GetCapturedStdout();
+        EXPECT_THAT(output, HasSubstr("Total wall time:"));
+        if (verbose) std::cout << output;
+        lmp = nullptr;
+    }
+};
+
+TEST(LAMMPS_config, package_count)
+{
+    EXPECT_EQ(lammps_config_package_count(), NUM_LAMMPS_PACKAGES);
+};
+
+TEST(LAMMPS_config, has_package)
+{
+    EXPECT_EQ(lammps_config_has_package("MANYBODY"), LAMMPS_HAS_MANYBODY);
+};
+