Enable Database OSS Tests (Desktop)

Moved files into tests/ folder and added CMakeLists.txt folder.  Updated some includes, etc to make the tests run on the OSS build.

PiperOrigin-RevId: 259786183

Author: ryanmeier

cmake/test_rules.cmake

@@ -23,7 +23,7 @@ include(CMakeParseArguments)
 # Defines a new test executable target with the given target name, sources, and
 # dependencies.  Implicitly adds DEPENDS on gtest and gtest_main.
 function(cc_test name)
-  set(multi DEPENDS SOURCES)
+  set(multi DEPENDS SOURCES INCLUDES DEFINES)
   # Parse the arguments into cc_test_SOURCES and cc_test_DEPENDS.
   cmake_parse_arguments(cc_test "" "" "${multi}" ${ARGN})
 
@@ -34,10 +34,12 @@ function(cc_test name)
   target_include_directories(${name}
     PRIVATE
       ${FIREBASE_SOURCE_DIR}
+      ${cc_test_INCLUDES}
   )
   target_link_libraries(${name} PRIVATE ${cc_test_DEPENDS})
   target_compile_definitions(${name}
     PRIVATE
       -DINTERNAL_EXPERIMENTAL=1
+      ${cc_test_DEFINES}
   )
 endfunction()

database/CMakeLists.txt

@@ -219,3 +219,8 @@ if(IOS)
   # Add a dependency to downloading the headers onto database.
   add_dependencies(firebase_database ${pod_target_name})
 endif()
+
+if(FIREBASE_CPP_BUILD_TESTS)
+  # Add the tests subdirectory
+  add_subdirectory(tests)
+endif()