diff --git a/Cargo.toml b/Cargo.toml
index 6905525..ffa054f 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -5,3 +5,6 @@ authors = ["Jason Travis Smith <Jason@CyberMagesLLC.com>"]
 
 [dependencies.sigils]
 git = "https://gitlab.com/CyberMages/sigils.git"
+
+[dev-dependencies]
+rand = "*"
diff --git a/src/endian.rs b/src/endian.rs
index 35f9267..a35eb6c 100644
--- a/src/endian.rs
+++ b/src/endian.rs
@@ -52,7 +52,7 @@ macro_rules! write_bytes
    ({
       use std::$valueType;
 
-      assert!($valueType::BYTES <= $buffer.len());
+      assert!($buffer.len() < $value_type::BYTES);
       unsafe
       {
          let size: usize;
diff --git a/tests/lib.rs b/tests/lib.rs
new file mode 100644
index 0000000..ae69ef7
--- /dev/null
+++ b/tests/lib.rs
@@ -0,0 +1,107 @@
+#![feature(zero_one)]
+#![feature(num_bits_bytes)]
+
+extern crate rand;
+
+extern crate alchemy;
+extern crate sigils;
+
+
+
+use rand::thread_rng;
+
+
+
+/// This should only be called by the macro below.
+macro_rules! overflow_impl
+{
+   ($numBytes: expr, $T: ident,
+    $read_func: ident, $write_func: ident) =>
+   {
+      use std::num::Zero;
+
+      use alchemy::{BigEndian, LittleEndian, Transmutable};
+
+
+
+      #[test]
+      #[should_panic]
+      fn read_big_endian()
+      {
+         let buffer: [u8; $numBytes];
+
+         buffer = [0u8; $numBytes];
+         BigEndian::$read_func(&buffer);
+      }
+
+      #[test]
+      #[should_panic]
+      fn read_little_endian()
+      {
+         let buffer: [u8; $numBytes];
+
+         buffer = [0u8; $numBytes];
+         LittleEndian::$read_func(&buffer);
+      }
+
+
+      #[test]
+      #[should_panic]
+      fn write_big_endian()
+      {
+         let mut buffer: [u8; $numBytes];
+
+         buffer = [0u8; $numBytes];
+         BigEndian::$write_func(&mut buffer, $T::zero());
+      }
+
+      #[test]
+      #[should_panic]
+      fn write_little_endian()
+      {
+         let mut buffer: [u8; $numBytes];
+
+         buffer = [0u8; $numBytes];
+            LittleEndian::$write_func(&mut buffer, $T::zero());
+      }
+   };
+}
+
+/// This macro tries to test for buffer overflow happening.
+macro_rules! test_buffer_overflow
+{
+   ($mod_name: ident, $T: ident,
+    $read_func: ident, $write_func: ident) =>
+   {
+      mod $mod_name
+      {
+         use std::$T;
+         overflow_impl!($T::BYTES, $T, $read_func, $write_func);
+      }
+   };
+
+   ($mod_name: ident, $T: ident,
+    $read_func: ident, $write_func: ident, $numBytes: expr) =>
+   {
+      mod $mod_name
+      {
+         overflow_impl!($numBytes, $T, $read_func, $write_func);
+      }
+   };
+}
+
+
+
+// Test the different data types for buffer overflow.
+test_buffer_overflow!(overflow_u16, u16, bytes_to_u16, u16_to_bytes);
+test_buffer_overflow!(overflow_u32, u32, bytes_to_u32, u32_to_bytes);
+test_buffer_overflow!(overflow_u64, u64, bytes_to_u64, u64_to_bytes);
+//test_buffer_overflow!(overflow_usize, usize, bytes_to_usize, usize_to_bytes);
+
+test_buffer_overflow!(overflow_i16, i16, bytes_to_i16, i16_to_bytes);
+test_buffer_overflow!(overflow_i32, i32, bytes_to_i32, i32_to_bytes);
+test_buffer_overflow!(overflow_i64, i64, bytes_to_i64, i64_to_bytes);
+//test_buffer_overflow!(overflow_isize, isize, bytes_to_isize, isize_to_bytes);
+
+test_buffer_overflow!(overflow_f32, f32, bytes_to_f32, f32_to_bytes, 4);
+test_buffer_overflow!(overflow_f64, f64, bytes_to_f64, f64_to_bytes, 8);