diff --git a/test/hmm_test.cpp b/test/hmm_test.cpp
index 62e5a57..05af7d6 100644
--- a/test/hmm_test.cpp
+++ b/test/hmm_test.cpp
@@ -38,6 +38,7 @@ TEST(Initialization, Vectors)
     //
     hmm_vec4 v4 = HMM_Vec4(1.0f, 2.0f, 3.0f, 4.0f);
     hmm_vec4 v4i = HMM_Vec4i(1, 2, 3, 4);
+    hmm_vec4 v4v = HMM_Vec4v(v3, 4.0f);
 
     EXPECT_FLOAT_EQ(v4.Elements[0], 1.0f);
     EXPECT_FLOAT_EQ(v4.Elements[1], 2.0f);
@@ -48,4 +49,37 @@ TEST(Initialization, Vectors)
     EXPECT_FLOAT_EQ(v4i.Elements[1], 2.0f);
     EXPECT_FLOAT_EQ(v4i.Elements[2], 3.0f);
     EXPECT_FLOAT_EQ(v4i.Elements[3], 4.0f);
+
+    EXPECT_FLOAT_EQ(v4v.Elements[0], 1.0f);
+    EXPECT_FLOAT_EQ(v4v.Elements[1], 2.0f);
+    EXPECT_FLOAT_EQ(v4v.Elements[2], 3.0f);
+    EXPECT_FLOAT_EQ(v4v.Elements[3], 4.0f);
+}
+
+TEST(Initialization, MatrixEmpty)
+{
+    hmm_mat4 m4 = HMM_Mat4();
+    for (int Column = 0; Column < 4; ++Column)
+    {
+        for (int Row = 0; Row < 4; ++Row)
+        {
+            EXPECT_FLOAT_EQ(m4.Elements[Column][Row], 0) << "At column " << Column << ", row " << Row;
+        }
+    }
+}
+
+TEST(Initialization, MatrixDiagonal)
+{
+    hmm_mat4 m4d = HMM_Mat4d(1.0f);
+    for (int Column = 0; Column < 4; ++Column)
+    {
+        for (int Row = 0; Row < 4; ++Row)
+        {
+            if (Column == Row) {
+                EXPECT_FLOAT_EQ(m4d.Elements[Column][Row], 1.0f) << "At column " << Column << ", row " << Row;
+            } else {
+                EXPECT_FLOAT_EQ(m4d.Elements[Column][Row], 0) << "At column " << Column << ", row " << Row;
+            }
+        }
+    }
 }