diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..1a4d940
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,33 @@
+# Prerequisites
+*.d
+
+# Compiled Object files
+*.slo
+*.lo
+*.o
+*.obj
+
+# Precompiled Headers
+*.gch
+*.pch
+
+# Compiled Dynamic libraries
+*.so
+*.dylib
+*.dll
+
+# Fortran module files
+*.mod
+*.smod
+
+# Compiled Static libraries
+*.lai
+*.la
+*.a
+*.lib
+
+# Executables
+*.exe
+*.out
+*.app
+hmm_test
diff --git a/.gitmodules b/.gitmodules
new file mode 100644
index 0000000..a78013a
--- /dev/null
+++ b/.gitmodules
@@ -0,0 +1,3 @@
+[submodule "externals/googletest"]
+	path = externals/googletest
+	url = https://github.com/google/googletest.git
diff --git a/README.md b/README.md
index 2427b3f..656f159 100644
--- a/README.md
+++ b/README.md
@@ -3,20 +3,20 @@
 Single-file public domain game math library for C/C++
 
 
-Version         | Changes | 
+Version         | Changes        | 
 ----------------|----------------|
-**0.5**     | Added scalar operations on vectors and matrices, added += and -= for hmm_mat4, reconciled headers and implementations, tidied up in general |
-**0.4**     | Added SSE Optimized HMM_SqrtF, HMM_RSqrtF, Removed use of CRT              | 
-**0.3**     | Added +=,-=, *=, /= for hmm_vec2, hmm_vec3, hmm_vec4              | 
-**0.2b**     | Disabled warning C4201 on MSVC, Added 64bit percision on HMM_PI              | 
-**0.2a**    | Prefixed Macros              | 
-**0.2**    | Updated Documentation, Fixed C Compliance, Prefixed all functions, and added better operator overloading               | 
-**0.1**     | Initial Version   | 
+**0.5**         | Added scalar operations on vectors and matrices, added += and -= for hmm_mat4, reconciled headers and implementations, tidied up in general |
+**0.4**         | Added SSE Optimized HMM_SqrtF, HMM_RSqrtF, Removed use of CRT | 
+**0.3**         | Added +=,-=, *=, /= for hmm_vec2, hmm_vec3, hmm_vec4 | 
+**0.2b**        | Disabled warning C4201 on MSVC, Added 64bit percision on HMM_PI | 
+**0.2a**        | Prefixed Macros | 
+**0.2**         | Updated Documentation, Fixed C Compliance, Prefixed all functions, and added better operator overloading | 
+**0.1**         | Initial Version | 
 
 _ID: In Development_
 
-## FAQ
 
+## FAQ
 
 **What's the license?**
 
@@ -24,4 +24,13 @@ This library is in the public domain. You can do whatever you want with them.
 
 **Where can I contact you to ask questions?**
 
-You can email me at: Zak@Handmade.Network
\ No newline at end of file
+You can email me at: Zak@Handmade.Network
+
+
+## Testing
+
+```shell
+cd test
+make
+./hmm_test
+```
diff --git a/externals/googletest b/externals/googletest
new file mode 160000
index 0000000..ed9d1e1
--- /dev/null
+++ b/externals/googletest
@@ -0,0 +1 @@
+Subproject commit ed9d1e1ff92ce199de5ca2667a667cd0a368482a
diff --git a/test/HandmadeMath.cpp b/test/HandmadeMath.cpp
new file mode 100644
index 0000000..5514f0b
--- /dev/null
+++ b/test/HandmadeMath.cpp
@@ -0,0 +1,5 @@
+
+#define HANDMADE_MATH_IMPLEMENTATION
+#define HANDMADE_MATH_CPP_MODE
+#define HANDMADE_MATH_NO_INLINE
+#include "../HandmadeMath.h"
diff --git a/test/Makefile b/test/Makefile
new file mode 100644
index 0000000..d17d47a
--- /dev/null
+++ b/test/Makefile
@@ -0,0 +1,81 @@
+# A sample Makefile for building Google Test and using it in user
+# tests.  Please tweak it to suit your environment and project.  You
+# may want to move it to your project's root directory.
+#
+# SYNOPSIS:
+#
+#   make [all]  - makes everything.
+#   make TARGET - makes the given target.
+#   make clean  - removes all files generated by make.
+
+# Please tweak the following variable definitions as needed by your
+# project, except GTEST_HEADERS, which you can use in your own targets
+# but shouldn't modify.
+
+# Points to the root of Google Test, relative to where this file is.
+# Remember to tweak this if you move this file.
+GTEST_DIR = ../externals/googletest/googletest
+
+# Where to find user code.
+USER_DIR = ..
+
+# Flags passed to the preprocessor.
+# Set Google Test's header directory as a system directory, such that
+# the compiler doesn't generate warnings in Google Test headers.
+CPPFLAGS += -isystem $(GTEST_DIR)/include
+
+# Flags passed to the C++ compiler.
+CXXFLAGS += -g -Wall -Wextra -pthread -Wno-missing-braces -Wno-missing-field-initializers
+
+# All tests produced by this Makefile.  Remember to add new tests you
+# created to the list.
+TESTS = hmm_test
+
+# All Google Test headers.  Usually you shouldn't change this
+# definition.
+GTEST_HEADERS = $(GTEST_DIR)/include/gtest/*.h \
+                $(GTEST_DIR)/include/gtest/internal/*.h
+
+# House-keeping build targets.
+
+all : $(TESTS)
+
+clean :
+	rm -f $(TESTS) gtest.a gtest_main.a *.o
+
+# Builds gtest.a and gtest_main.a.
+
+# Usually you shouldn't tweak such internal variables, indicated by a
+# trailing _.
+GTEST_SRCS_ = $(GTEST_DIR)/src/*.cc $(GTEST_DIR)/src/*.h $(GTEST_HEADERS)
+
+# For simplicity and to avoid depending on Google Test's
+# implementation details, the dependencies specified below are
+# conservative and not optimized.  This is fine as Google Test
+# compiles fast and for ordinary users its source rarely changes.
+gtest-all.o : $(GTEST_SRCS_)
+	$(CXX) $(CPPFLAGS) -I$(GTEST_DIR) $(CXXFLAGS) -c \
+            $(GTEST_DIR)/src/gtest-all.cc
+
+gtest_main.o : $(GTEST_SRCS_)
+	$(CXX) $(CPPFLAGS) -I$(GTEST_DIR) $(CXXFLAGS) -c \
+            $(GTEST_DIR)/src/gtest_main.cc
+
+gtest.a : gtest-all.o
+	$(AR) $(ARFLAGS) $@ $^
+
+gtest_main.a : gtest-all.o gtest_main.o
+	$(AR) $(ARFLAGS) $@ $^
+
+# Builds a sample test.  A test should link with either gtest.a or
+# gtest_main.a, depending on whether it defines its own main()
+# function.
+
+HandmadeMath.o : $(USER_DIR)/test/HandmadeMath.cpp $(USER_DIR)/HandmadeMath.h $(GTEST_HEADERS)
+	$(CXX) $(CPPFLAGS) $(CXXFLAGS) -c $(USER_DIR)/test/HandmadeMath.cpp
+
+hmm_test.o : $(USER_DIR)/test/hmm_test.cpp $(GTEST_HEADERS)
+	$(CXX) $(CPPFLAGS) $(CXXFLAGS) -c $(USER_DIR)/test/hmm_test.cpp
+
+hmm_test : HandmadeMath.o hmm_test.o gtest_main.a
+	$(CXX) $(CPPFLAGS) $(CXXFLAGS) -lpthread $^ -o $@
diff --git a/test/hmm_test.cpp b/test/hmm_test.cpp
new file mode 100644
index 0000000..62e5a57
--- /dev/null
+++ b/test/hmm_test.cpp
@@ -0,0 +1,51 @@
+
+#define HANDMADE_MATH_CPP_MODE
+#include "../HandmadeMath.h"
+
+#include "gtest/gtest.h"
+
+
+TEST(Initialization, Vectors)
+{
+    //
+    // Test vec2
+    // 
+    hmm_vec2 v2 = HMM_Vec2(1.0f, 2.0f);
+    hmm_vec2 v2i = HMM_Vec2(1, 2);
+
+    EXPECT_FLOAT_EQ(v2.Elements[0], 1.0f);
+    EXPECT_FLOAT_EQ(v2.Elements[1], 2.0f);
+
+    EXPECT_FLOAT_EQ(v2i.Elements[0], 1.0f);
+    EXPECT_FLOAT_EQ(v2i.Elements[1], 2.0f);
+
+    //
+    // Test vec3
+    //
+    hmm_vec3 v3 = HMM_Vec3(1.0f, 2.0f, 3.0f);
+    hmm_vec3 v3i = HMM_Vec3i(1, 2, 3);
+
+    EXPECT_FLOAT_EQ(v3.Elements[0], 1.0f);
+    EXPECT_FLOAT_EQ(v3.Elements[1], 2.0f);
+    EXPECT_FLOAT_EQ(v3.Elements[2], 3.0f);
+
+    EXPECT_FLOAT_EQ(v3i.Elements[0], 1.0f);
+    EXPECT_FLOAT_EQ(v3i.Elements[1], 2.0f);
+    EXPECT_FLOAT_EQ(v3i.Elements[2], 3.0f);
+
+    //
+    // Test vec4
+    //
+    hmm_vec4 v4 = HMM_Vec4(1.0f, 2.0f, 3.0f, 4.0f);
+    hmm_vec4 v4i = HMM_Vec4i(1, 2, 3, 4);
+
+    EXPECT_FLOAT_EQ(v4.Elements[0], 1.0f);
+    EXPECT_FLOAT_EQ(v4.Elements[1], 2.0f);
+    EXPECT_FLOAT_EQ(v4.Elements[2], 3.0f);
+    EXPECT_FLOAT_EQ(v4.Elements[3], 4.0f);
+
+    EXPECT_FLOAT_EQ(v4i.Elements[0], 1.0f);
+    EXPECT_FLOAT_EQ(v4i.Elements[1], 2.0f);
+    EXPECT_FLOAT_EQ(v4i.Elements[2], 3.0f);
+    EXPECT_FLOAT_EQ(v4i.Elements[3], 4.0f);
+}