diff --git a/.github/workflows/linux.yml b/.github/workflows/linux.yml
index 4a4bc003..85f43796 100644
--- a/.github/workflows/linux.yml
+++ b/.github/workflows/linux.yml
@@ -45,12 +45,17 @@ jobs:
           CC: ${{ steps.vars.outputs.cc }}
           CXX: ${{ steps.vars.outputs.cxx }}
       run: |
-        cmake -DCMAKE_BUILD_TYPE=RelWithDebInfo -B build
+        cmake -DCMAKE_BUILD_TYPE=RelWithDebInfo -DBUILD_TESTS=ON -B build
         
     - name: Build Dethrace
       run: |
         cmake --build build -- -j 4
 
+    - name: Run unit tests
+      run: |
+        cd build
+        ctest
+
     - name: Create archives
       run: |
         mkdir artifact
diff --git a/.github/workflows/macos.yml b/.github/workflows/macos.yml
index 47e7575c..01d08f97 100644
--- a/.github/workflows/macos.yml
+++ b/.github/workflows/macos.yml
@@ -25,12 +25,17 @@ jobs:
         
     - name: Configure Dethrace
       run: |
-        cmake -DCMAKE_BUILD_TYPE=RelWithDebInfo -B build
+        cmake -DCMAKE_BUILD_TYPE=RelWithDebInfo -DBUILD_TESTS=ON -B build
         
     - name: Build Dethrace
       run: |
         cmake --build build -- -j 4
 
+    - name: Run unit tests
+      run: |
+        cd build
+        ctest
+
     - name: Create archives
       run: |
         mkdir artifact
diff --git a/CMakeLists.txt b/CMakeLists.txt
index f3010b5e..164bc4f9 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,6 +10,8 @@ project(dethrace C)
 
 set(CMAKE_RUNTIME_OUTPUT_DIRECTORY ${CMAKE_BINARY_DIR})
 
+option(BUILD_TESTS "Build unit tests." OFF)
+
 find_package(SDL2 REQUIRED)
 
 add_subdirectory(lib/libsmacker)
@@ -19,3 +21,8 @@ add_subdirectory(lib/glad)
 add_subdirectory(src/harness)
 add_subdirectory(src/BRSRC13)
 add_subdirectory(src/DETHRACE)
+
+if(BUILD_TESTS)
+    enable_testing()
+    add_subdirectory(test)
+endif()
diff --git a/src/DETHRACE/CMakeLists.txt b/src/DETHRACE/CMakeLists.txt
index 0f7e793e..4c8305fe 100644
--- a/src/DETHRACE/CMakeLists.txt
+++ b/src/DETHRACE/CMakeLists.txt
@@ -1,6 +1,7 @@
-add_executable(dethrace)
+# Create object files so we can link them into the main binary and into tests without building twice.
+add_library(dethrace_obj OBJECT)
 
-target_include_directories(dethrace PRIVATE
+target_include_directories(dethrace_obj PUBLIC
     .
     common
     pc-dos
@@ -9,32 +10,24 @@ target_include_directories(dethrace PRIVATE
     ${CMAKE_SOURCE_DIR}/src/BRSRC13
 )
 
-target_link_libraries(dethrace PRIVATE smacker harness brender miniposix SDL2::SDL2 glad)
+target_link_libraries(dethrace_obj PUBLIC miniposix SDL2::SDL2 smacker harness brender)
 
 if(NOT MSVC)
-    target_compile_options(dethrace PRIVATE
+    target_compile_options(dethrace_obj PRIVATE
         -g
         -Wno-return-type
         -Wno-missing-declarations
         -Werror=implicit-function-declaration
     )
-
-    if(APPLE)
-        target_link_libraries(dethrace PRIVATE "-framework OpenGL")
-    else()
-        target_link_libraries(dethrace PRIVATE GL)
-    endif()
 else()
-    target_compile_definitions(dethrace PRIVATE -D_CRT_SECURE_NO_WARNINGS -DSDL_MAIN_HANDLED)
-    target_compile_options(dethrace PRIVATE
+    target_compile_definitions(dethrace_obj PRIVATE -D_CRT_SECURE_NO_WARNINGS)
+    target_compile_options(dethrace_obj PRIVATE
         /wd4101
         /wd4996
     )
-    target_link_libraries(dethrace PRIVATE dbghelp)
-    target_link_options(dethrace PRIVATE /subsystem:windows /ENTRY:mainCRTStartup)
 endif()
 
-target_sources(dethrace PRIVATE
+target_sources(dethrace_obj PRIVATE
     common/brucetrk.c
     common/brucetrk.h
     common/car.c
@@ -139,11 +132,27 @@ target_sources(dethrace PRIVATE
     common/world.h
     constants.h
     dr_types.h
-    main.c
     pc-dos/dosnet.c
     pc-dos/dosnet.h
     pc-dos/dossys.c
     pc-dos/dossys.h
     watcom_functions.c
     watcom_functions.h
-)
\ No newline at end of file
+)
+
+# Create our main game binary.
+add_executable(dethrace)
+target_link_libraries(dethrace PRIVATE glad dethrace_obj)
+target_sources(dethrace PRIVATE main.c)
+
+if(NOT MSVC)
+    if(APPLE)
+        target_link_libraries(dethrace PRIVATE "-framework OpenGL")
+    else()
+        target_link_libraries(dethrace PRIVATE GL)
+    endif()
+else()
+    target_link_libraries(dethrace PRIVATE dbghelp)
+    target_link_options(dethrace PRIVATE /subsystem:windows /ENTRY:mainCRTStartup)
+    target_compile_definitions(dethrace PRIVATE -D_CRT_SECURE_NO_WARNINGS -DSDL_MAIN_HANDLED)
+endif()
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
new file mode 100644
index 00000000..14db3673
--- /dev/null
+++ b/test/CMakeLists.txt
@@ -0,0 +1,56 @@
+add_executable(dethrace_test)
+add_test(NAME teat_dethrace COMMAND dethrace_test)
+
+target_link_libraries(dethrace_test PRIVATE glad dethrace_obj)
+
+target_include_directories(dethrace_test PRIVATE
+    .
+    ${CMAKE_SOURCE_DIR}/lib
+    ${CMAKE_SOURCE_DIR}/src/harness
+    ${CMAKE_SOURCE_DIR}/src/BRSRC13
+    ${CMAKE_SOURCE_DIR}/src/DETHRACE
+    ${CMAKE_SOURCE_DIR}/src/DETHRACE/common
+    ${CMAKE_SOURCE_DIR}/src/DETHRACE/pc-dos
+)
+
+if(NOT MSVC)
+    if(APPLE)
+        target_link_libraries(dethrace_test PRIVATE "-framework OpenGL")
+    else()
+        target_link_libraries(dethrace_test PRIVATE GL)
+    endif()
+else()
+    target_compile_definitions(dethrace_test PRIVATE -D_CRT_SECURE_NO_WARNINGS -DSDL_MAIN_HANDLED)
+    target_link_libraries(dethrace_test PRIVATE dbghelp)
+endif()
+
+target_sources(dethrace_test PRIVATE
+    BRSRC13/test_actsupt.c
+    BRSRC13/test_brlists.c
+    BRSRC13/test_datafile.c
+    BRSRC13/test_fwsetup.c
+    BRSRC13/test_genclip.c
+    BRSRC13/test_pattern.c
+    BRSRC13/test_pmfile.c
+    BRSRC13/test_register.c
+    BRSRC13/test_regsupt.c
+    BRSRC13/test_resource.c
+    BRSRC13/test_resreg.c
+    BRSRC13/test_v1dbfile.c
+    DETHRACE/test_controls.c
+    DETHRACE/test_dossys.c
+    DETHRACE/test_errors.c
+    DETHRACE/test_flicplay.c
+    DETHRACE/test_graphics.c
+    DETHRACE/test_init.c
+    DETHRACE/test_input.c
+    DETHRACE/test_loading.c
+    DETHRACE/test_powerup.c
+    DETHRACE/test_utility.c
+    framework/unity.c
+    framework/unity.h
+    framework/unity_internals.h
+    framework
+    main.c
+    tests.h
+)
\ No newline at end of file