add googletest

CMakeLists.txt

@@ -102,6 +102,7 @@ option (BUILD_TEST_APPS "Build test applications" OFF)
 option (DIST_INSTALLER "Generate installer for distributing vapor binaries. Will generate standard make install if off" OFF)
 option (USE_OMP "Use OpenMP on some calculations" OFF)
 option (CONDA_BUILD "Use Conda to build" OFF)
+option( BUILD_GOOGLE_TEST "Build unit tests using GoogleTest" OFF )
 if (UNIX AND NOT APPLE)
     include (CMakeDependentOption)
     cmake_dependent_option (DIST_APPIMAGE "Generate an AppImage for VAPOR's installation across multiple Linux platforms" OFF "DIST_INSTALLER" ON)
@@ -116,6 +117,34 @@ if( USE_OMP )
     endif()
 endif()
 
+#
+# Build Google Test
+#
+if( BUILD_GOOGLE_TEST )
+  # Control internal options of GoogleTest
+  #
+  set( INSTALL_GTEST OFF CACHE INTERNAL "Not install GoogleTest")
+  set( BUILD_GMOCK ON CACHE INTERNAL "Build gmock")
+
+  # Let's use the new mechanism to incorporate GoogleTest
+  #
+  include(FetchContent)
+  if(${CMAKE_VERSION} VERSION_GREATER_EQUAL "3.24")
+    FetchContent_Declare( googletest
+      URL https://github.com/google/googletest/archive/refs/heads/main.zip
+      DOWNLOAD_EXTRACT_TIMESTAMP NEW )
+  endif()
+
+  # Prevent overriding the parent project's compiler/linker settings on Windows
+  #
+  set(gtest_force_shared_crt ON CACHE BOOL "" FORCE)
+  FetchContent_MakeAvailable(googletest)
+
+  enable_testing() # calling this function before adding subdirectory to enable 
+                   # invoking ctest from the top-level build directory.
+  add_subdirectory( googletest_scripts )
+endif()
+
 set (GENERATE_FULL_INSTALLER ON)
 if (BUILD_GUI)
 	set (BUILD_VDC ON)

googletest_scripts/CMakeLists.txt

@@ -0,0 +1,10 @@
+# Add an executable that tests a specific part of VAPOR.
+add_executable( ptr_cache_test ptr_cache_test.cpp )
+target_include_directories( ptr_cache_test PRIVATE ${PROJECT_SOURCE_DIR}/include/vapor/ )
+target_link_libraries( ptr_cache_test PUBLIC GTest::gtest_main )
+
+
+include(GoogleTest)
+
+# Enable this executable to be tested using `ctest .`
+gtest_discover_tests( ptr_cache_test )

googletest_scripts/ptr_cache_test.cpp

@@ -0,0 +1,112 @@
+#include "gtest/gtest.h"
+
+#include "ptr_cache.hpp" // Only include the module that's tested
+
+namespace {
+
+struct MyObj {
+  int i = 0, j = 1; 
+};
+
+// Besides correct insertion/query/eviction behaviors the `ptr_cache` has to be
+// deleting objects correctly upon eviction. However, memory errors are not 
+// something GoogleTest can detect. As a result, one needs to run this
+// executable in valgrind to make sure that there are no memory errors:
+// valgrind ./googletest_scripts/ptr_cache_test
+
+// Test the cache when queries don't count as a use.
+// It needs to insert and evict correctly.
+TEST(ptr_cache_query_false, insert_eviction)
+{
+  VAPoR::ptr_cache<int, MyObj, 3, false> cache;
+  const auto* p = cache.query(1);
+  EXPECT_EQ(p, nullptr); // nothing in the cache yet, should get nullptr
+
+  cache.insert(1, new MyObj{1, 100});
+  cache.insert(2, new MyObj{2, 200});
+  cache.insert(3, new MyObj{3, 300});
+
+  // Make sure that we have all 3 objects
+  p = cache.query(1);
+  EXPECT_NE(p, nullptr); // not nullptr
+  EXPECT_EQ(p->j, 100);
+  p = cache.query(2);
+  EXPECT_NE(p, nullptr);
+  EXPECT_EQ(p->j, 200);
+  p = cache.query(3);
+  EXPECT_NE(p, nullptr);
+  EXPECT_EQ(p->j, 300);
+  p = cache.query(4);
+  EXPECT_EQ(p, nullptr);
+
+  // Insert a new object; make sure that "1" is evicted.
+  cache.insert(4, new MyObj{4, 400});
+  p = cache.query(4);
+  EXPECT_NE(p, nullptr);
+  EXPECT_EQ(p->j, 400);
+  p = cache.query(1);
+  EXPECT_EQ(p, nullptr);
+
+  // Do a query on "2", but queries don't count as a use.
+  p = cache.query(2);
+
+  // Insert another object; make sure that "2" is evicted.
+  cache.insert(5, new MyObj{5, 500});
+  p = cache.query(5);
+  EXPECT_NE(p, nullptr);
+  EXPECT_EQ(p->j, 500);
+  p = cache.query(2);
+  EXPECT_EQ(p, nullptr);
+}
+
+
+// Test the cache when queries count as a use.
+TEST(ptr_cache_query_true, insert_eviction)
+{
+  VAPoR::ptr_cache<int, MyObj, 3, true> cache;
+
+  cache.insert(1, new MyObj{1, 100});
+  cache.insert(2, new MyObj{2, 200});
+  cache.insert(3, new MyObj{3, 300});
+
+  // Make sure that we have all 3 objects
+  const auto* p = cache.query(1);
+  EXPECT_NE(p, nullptr); // not nullptr
+  EXPECT_EQ(p->j, 100);
+  p = cache.query(2);
+  EXPECT_NE(p, nullptr);
+  EXPECT_EQ(p->j, 200);
+  p = cache.query(3);
+  EXPECT_NE(p, nullptr);
+  EXPECT_EQ(p->j, 300);
+  p = cache.query(4);
+  EXPECT_EQ(p, nullptr);
+
+  // Insert a new object; make sure that "1" is evicted.
+  cache.insert(4, new MyObj{4, 400});
+  p = cache.query(4);
+  EXPECT_NE(p, nullptr);
+  EXPECT_EQ(p->j, 400);
+  p = cache.query(1);
+  EXPECT_EQ(p, nullptr);
+
+  // Do a query on "2", then insert, it should be "3" that's evicted.
+  p = cache.query(2);
+  cache.insert(5, new MyObj{5, 500});
+  p = cache.query(5);
+  EXPECT_NE(p, nullptr);
+  EXPECT_EQ(p->j, 500);
+  p = cache.query(3);
+  EXPECT_EQ(p, nullptr);
+
+  // Do another query on "2", then insert, it should be "4" that's evicted.
+  p = cache.query(2);
+  cache.insert(6, new MyObj{6, 600});
+  p = cache.query(6);
+  EXPECT_NE(p, nullptr);
+  EXPECT_EQ(p->j, 600);
+  p = cache.query(4);
+  EXPECT_EQ(p, nullptr);
+}
+
+} // End of namespace