Load the test file into your running Lisp implementation, for example,
`(load "point-mutations-test")`. This will run the tests the first
time automatically. After that you can run the test suite in the REPL
with `(lisp-unit:run-tests :all :point-mutations-test)`.

## Making your first Common Lisp solution

To create lisp code that can be loaded with `(load "dna")`
for the first exercise, put this code in `dna.lisp`:

```lisp
(in-package #:cl-user)
(defpackage #:dna
  (:use #:common-lisp)
  (:export #:hamming-distance))

(in-package #:dna)

(defun hamming-distance (dna1 dna2)
  "Determine number of mutations between DNA strands by computing the Hamming Distance."
  )
```

Start up your Lisp implementation in the directory of the exercise you
are working on (or change the current directory for an already running
Lisp implementation to that directory).

Load the test file into your running Lisp implementation, for example,
`(load "point-mutations-test")`. This will run the tests the first
time automatically. After that you can run the test suite in the REPL
with `(lisp-unit:run-tests :all :point-mutations-test)`.

## Making your first Common Lisp solution

To create lisp code that can be loaded with `(load "dna")`
for the first exercise, put this code in `dna.lisp`:

```lisp
(in-package #:cl-user)
(defpackage #:dna
  (:use #:common-lisp)
  (:export #:hamming-distance))

(in-package #:dna)

(defun hamming-distance (dna1 dna2)
  "Determine number of mutations between DNA strands by computing the Hamming Distance."
  )
```

Add instruction of default-directory for implementation.
Add instruction of default-directory for implementation.
