diff --git a/CMakeLists.txt b/CMakeLists.txt
index 508a4462..41da32f8 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -4,10 +4,8 @@ project(xlnt_all)
 # This indicates to CMakeLists in subdirectories that they are part of a larger project
 set(COMBINED_PROJECT TRUE)
 
-option(BUILD_DEPS "Set to ON to build zlib and cryptopp from source otherwise system libraries will be used for these" OFF)
-
 # Library type
-option(STATIC "Set to ON to build ${PROJECT_NAME} as a static library instead of a shared library" OFF)
+option(STATIC "Set to ON to build xlnt as a static library instead of a shared library" OFF)
 
 # Optional components
 option(SAMPLES "Set to ON to build executable code samples (in ./samples)" OFF)
@@ -28,11 +26,14 @@ if(BENCHMARKS)
 endif()
 
 find_package(PythonInterp)
+find_package(CxxTest)
 
-if(PYTHONINTERP_FOUND)
+if(PYTHONINTERP_FOUND AND CXXTEST_FOUND)
     add_subdirectory(tests)
-else()
+elseif(NOT PYTHONINTERP_FOUND)
     message("Python couldn't be found in the current PATH but is required for building tests. Tests will be skipped for now.")
+else()
+    message("CxxTest couldn't be found in the current PATH but is required for building tests. Tests will be skipped for now.")
 endif()
 
 add_subdirectory(source)
diff --git a/source/CMakeLists.txt b/source/CMakeLists.txt
index 450d35b1..99136e8e 100644
--- a/source/CMakeLists.txt
+++ b/source/CMakeLists.txt
@@ -11,9 +11,6 @@ set(PROJECT_DESCRIPTION "cross-platform user-friendly xlsx library for C++14")
 
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_CURRENT_SOURCE_DIR}/../third-party")
 
-find_package(ZLIB REQUIRED)
-find_package(CryptoPP REQUIRED)
-
 if(APPLE)
     option(FRAMEWORK "Set to ON to package dylib and headers into a .framework, OSX only" OFF)
 endif()
@@ -127,16 +124,25 @@ else()
     endif()
 endif()
 
-target_link_libraries(xlnt
-    PRIVATE ${CRYPTOPP_LIBRARY}
-    PRIVATE ${ZLIB_LIBRARY_RELEASE}
-    PRIVATE libstudxml)
+add_dependencies(xlnt xlnt.third-party)
 
-target_include_directories(xlnt
-    PUBLIC ${XLNT_INCLUDE_DIR}
-    PRIVATE ${XLNT_SOURCE_DIR}
-    PRIVATE ${ZLIB_INCLUDE_DIR}
-    PRIVATE ${CRYPTOPP_INCLUDE_DIR})
+target_link_libraries(xlnt PRIVATE libstudxml)
+target_include_directories(xlnt PUBLIC ${XLNT_INCLUDE_DIR})
+target_include_directories(xlnt PRIVATE ${XLNT_SOURCE_DIR})
+
+if(LOCAL_ZLIB OR LOCAL_DEPENDENCIES)
+    target_link_libraries(xlnt PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third-party/zlib/zlib-download-prefix/src/zlib-download-build/libz.a)
+else()
+    target_link_libraries(xlnt PRIVATE ${ZLIB_LIBRARY_RELEASE})
+    target_include_directories(xlnt PRIVATE ${ZLIB_INCLUDE_DIR})
+endif()
+
+if(LOCAL_CRYPTOPP OR LOCAL_DEPENDENCIES)
+    target_link_libraries(xlnt PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third-party/cryptopp/cryptopp-download-prefix/src/cryptopp-download-build/libcryptopp.a)
+else()
+    target_link_libraries(xlnt PRIVATE ${CRYPTOPP_LIBRARY_RELEASE})
+    target_include_directories(xlnt PRIVATE ${CRYPTOPP_INCLUDE_DIR})
+endif()
 
 if(MSVC)
     set_target_properties(xlnt PROPERTIES COMPILE_FLAGS "/wd\"4251\" /wd\"4275\" /wd\"4068\" /MP")
diff --git a/source/detail/zstream.hpp b/source/detail/zstream.hpp
index 938b83b8..b1ae6473 100644
--- a/source/detail/zstream.hpp
+++ b/source/detail/zstream.hpp
@@ -49,7 +49,7 @@ namespace detail {
 /// A structure representing the header that occurs before each compressed file in a ZIP
 /// archive and again at the end of the file with more information.
 /// </summary>
-struct zheader
+struct XLNT_API zheader
 {
     std::uint16_t version = 20;
     std::uint16_t flags = 0;
@@ -69,7 +69,7 @@ struct zheader
 /// Writes a series of uncompressed binary file data as ostreams into another ostream
 /// according to the ZIP format.
 /// </summary>
-class ozstream
+class XLNT_API ozstream
 {
 public:
     /// <summary>
@@ -96,7 +96,7 @@ private:
 /// Reads an archive containing a number of files from an istream and allows them
 /// to be decompressed into an istream.
 /// </summary>
-class izstream
+class XLNT_API izstream
 {
 public:
     /// <summary>
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 9841ba0e..3711a047 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -8,9 +8,6 @@ if(NOT COMBINED_PROJECT)
     add_subdirectory(${LIBRARY_SOURCE_DIR} ${CMAKE_CURRENT_BINARY_DIR}/source)
 endif()
 
-find_package(CxxTest REQUIRED)
-find_package(ZLIB REQUIRED)
-
 file(GLOB CELL_TESTS ${CMAKE_CURRENT_SOURCE_DIR}/../source/cell/tests/test_*.hpp)
 file(GLOB CHARTS_TESTS ${CMAKE_CURRENT_SOURCE_DIR}/../source/charts/tests/test_*.hpp)
 file(GLOB CHARTSHEET_TESTS ${CMAKE_CURRENT_SOURCE_DIR}/../source/chartsheet/tests/test_*.hpp)
@@ -22,10 +19,6 @@ file(GLOB UTILS_TESTS ${CMAKE_CURRENT_SOURCE_DIR}/../source/utils/tests/test_*.h
 file(GLOB WORKBOOK_TESTS ${CMAKE_CURRENT_SOURCE_DIR}/../source/workbook/tests/test_*.hpp)
 file(GLOB WORKSHEET_TESTS ${CMAKE_CURRENT_SOURCE_DIR}/../source/worksheet/tests/test_*.hpp)
 
-set(XLNT_ZIP
-    ${CMAKE_CURRENT_SOURCE_DIR}/../source/detail/zstream.cpp
-    ${CMAKE_CURRENT_SOURCE_DIR}/../source/detail/zstream.hpp)
-
 set(TESTS ${CELL_TESTS} ${CHARTS_TESTS} ${CHARTSHEET_TESTS} ${DRAWING_TESTS} 
     ${FORMULA_TESTS} ${PACKAGING_TESTS} ${STYLES_TESTS} ${UTILS_TESTS} 
 	${WORKBOOK_TESTS} ${WORKSHEET_TESTS})
@@ -43,10 +36,9 @@ if(COVERAGE)
     set(CMAKE_EXE_LINKER_FLAGS "${CMAKE_EXE_LINKER_FLAGS} -lgcov --coverage")
 endif()
 
-add_executable(xlnt.test ${TEST_HELPERS} ${TESTS} ${RUNNER} ${XLNT_ZIP})
+add_executable(xlnt.test ${TEST_HELPERS} ${TESTS} ${RUNNER})
 target_link_libraries(xlnt.test
-    PRIVATE xlnt
-    PRIVATE ${ZLIB_LIBRARIES})
+    PRIVATE xlnt)
 target_include_directories(xlnt.test
     PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
     PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/../source
@@ -79,6 +71,7 @@ else()
 endif()
 
 find_package(PythonInterp REQUIRED)
+find_package(CxxTest REQUIRED)
 
 add_custom_command(OUTPUT ${RUNNER}
     COMMAND ${CXXTEST_PYTHON_TESTGEN_EXECUTABLE} --runner=ErrorPrinter -o ${RUNNER} ${TESTS}
diff --git a/third-party/CMakeLists.txt b/third-party/CMakeLists.txt
index 2b3d8f05..11e1fa2e 100644
--- a/third-party/CMakeLists.txt
+++ b/third-party/CMakeLists.txt
@@ -1,11 +1,10 @@
 cmake_minimum_required(VERSION 3.2)
-project(program)
+project(xlnt.third-party)
 
 set(CMAKE_MODULE_PATH ${CMAKE_MODULE_PATH} "${CMAKE_CURRENT_SOURCE_DIR}")
-add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/libstudxml)
 
-if(BUILD_DEPS)
-    add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/zlib)
-    add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/cryptopp)
-    add_dependencies(libstudxml zlib-download cryptopp-download)
-endif()
+add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/libstudxml)
+add_subdirectory(${CMAKE_CURRENT_SOURCE_DIR}/cxxtest)
+
+add_custom_target(xlnt.third-party
+    DEPENDS libstudxml cxxtest-download)
diff --git a/third-party/cryptopp/CMakeLists.txt b/third-party/cryptopp/CMakeLists.txt
deleted file mode 100644
index 56ce025e..00000000
--- a/third-party/cryptopp/CMakeLists.txt
+++ /dev/null
@@ -1,22 +0,0 @@
-cmake_minimum_required(VERSION 3.2)
-project(cryptopp)
-
-set(CMAKE_CXX_STANDARD 14)
-set(CMAKE_CXX_STANDARD_REQUIRED ON)
-
-include(ExternalProject)
-ExternalProject_Add(cryptopp-download
-    GIT_REPOSITORY https://github.com/weidai11/cryptopp
-    INSTALL_COMMAND "")
-
-set(CRYPTOPP_ROOT_DIR ${CMAKE_CURRENT_BINARY_DIR}/cryptopp-download-prefix/src/cryptopp-download)
-set(CRYPTOPP_INCLUDE_DIR ${CRYPTOPP_ROOT_DIR})
-set(CRYPTOPP_BUILD_DIR ${CMAKE_CURRENT_BINARY_DIR}/cryptopp-download-prefix/src/cryptopp-download-build)
-
-add_library(cryptopp STATIC IMPORTED)
-set_property(TARGET cryptopp PROPERTY IMPORTED_LOCATION ${CRYPTOPP_BUILD_DIR}/libcryptopp.a)
-add_dependencies(cryptopp cryptopp-download)
-
-if(NOT STATIC)
-    set_target_properties(cryptopp PROPERTIES POSITION_INDEPENDENT_CODE 1)
-endif()
diff --git a/third-party/cxxtest/CMakeLists.txt b/third-party/cxxtest/CMakeLists.txt
index 8ab37b2e..18d27c62 100644
--- a/third-party/cxxtest/CMakeLists.txt
+++ b/third-party/cxxtest/CMakeLists.txt
@@ -7,8 +7,11 @@ set(CMAKE_CXX_STANDARD_REQUIRED ON)
 include(ExternalProject)
 ExternalProject_Add(cxxtest-download
     GIT_REPOSITORY https://github.com/CxxTest/cxxtest
+    CONFIGURE_COMMAND ""
+    BUILD_COMMAND ""
     INSTALL_COMMAND "")
 
 set(CXXTEST_ROOT_DIR ${CMAKE_CURRENT_BINARY_DIR}/cxxtest-download-prefix/src/cxxtest-download)
 set(CXXTEST_INCLUDE_DIR ${CXXTEST_ROOT_DIR})
+set(CXXTEST_PYTHON_TESTGEN_EXECUTABLE ${CXXTEST_ROOT_DIR}/bin/cxxtestgen CACHE INTERNAL "" FORCE)
 
diff --git a/third-party/libstudxml/CMakeLists.txt b/third-party/libstudxml/CMakeLists.txt
index 857c3241..fea24c28 100644
--- a/third-party/libstudxml/CMakeLists.txt
+++ b/third-party/libstudxml/CMakeLists.txt
@@ -25,7 +25,7 @@ set(GENX
     ${LIBSTUDXML_ROOT_DIR}/xml/details/genx/genx.c
     ${LIBSTUDXML_ROOT_DIR}/xml/details/genx/genx.h)
 
-if(BUILD_DEPS)
+if(LOCAL_EXPAT OR LOCAL_DEPENDENCIES)
     set(EXPAT
         ${LIBSTUDXML_ROOT_DIR}/xml/details/expat/xmlparse.c
         ${LIBSTUDXML_ROOT_DIR}/xml/details/expat/xmlrole.c
@@ -51,7 +51,7 @@ add_library(libstudxml STATIC ${LIBSTUDXML} ${GENX} ${EXPAT})
 target_compile_definitions(libstudxml PUBLIC LIBSTUDXML_STATIC_LIB=1)
 target_include_directories(libstudxml PUBLIC ${LIBSTUDXML_ROOT_DIR})
 
-if(NOT BUILD_DEPS)
+if(NOT LOCAL_EXPAT AND NOT LOCAL_DEPENDENCIES)
     find_package(EXPAT REQUIRED)
     target_compile_definitions(libstudxml PRIVATE LIBSTUDXML_EXTERNAL_EXPAT=1)
     target_link_libraries(libstudxml PRIVATE expat)
diff --git a/third-party/zlib/CMakeLists.txt b/third-party/zlib/CMakeLists.txt
deleted file mode 100644
index a009c9e1..00000000
--- a/third-party/zlib/CMakeLists.txt
+++ /dev/null
@@ -1,18 +0,0 @@
-cmake_minimum_required(VERSION 3.2)
-project(zlib)
-
-set(CMAKE_CXX_STANDARD 14)
-set(CMAKE_CXX_STANDARD_REQUIRED ON)
-
-include(ExternalProject)
-ExternalProject_Add(zlib-download
-    GIT_REPOSITORY https://github.com/madler/zlib
-    INSTALL_COMMAND "")
-
-set(ZLIB_ROOT_DIR ${CMAKE_CURRENT_BINARY_DIR}/zlib-download-prefix/src/zlib-download)
-set(ZLIB_INCLUDE_DIR ${ZLIB_ROOT_DIR})
-set(ZLIB_BUILD_DIR ${CMAKE_CURRENT_BINARY_DIR}/zlib-download-prefix/src/zlib-download-build)
-
-add_library(zlib STATIC IMPORTED)
-set_property(TARGET zlib PROPERTY IMPORTED_LOCATION ${ZLIB_BUILD_DIR}/libz.a)
-add_dependencies(zlib zlib-download)