From d872515343bd19cc3780ce8a9b118d3848c11363 Mon Sep 17 00:00:00 2001
From: JoseALermaIII <jose@JoseALerma.com>
Date: Sun, 13 Oct 2019 11:43:02 -0500
Subject: [PATCH 01/14] Initial commit

---
 src/ch07/c2_safe_cracker.py | 11 +++++++++++
 1 file changed, 11 insertions(+)
 create mode 100644 src/ch07/c2_safe_cracker.py

diff --git a/src/ch07/c2_safe_cracker.py b/src/ch07/c2_safe_cracker.py
new file mode 100644
index 0000000..05df8f1
--- /dev/null
+++ b/src/ch07/c2_safe_cracker.py
@@ -0,0 +1,11 @@
+"""Use hill-climbing algorithm to solve a lock combination.
+
+Solve a lock combination by randomly changing a tumbler's values one
+by one and noting whether the safe had a response. If so, lock the
+tumbler at that value and continue randomly changing tumbler values.
+
+Previously, a locked tumbler can still be changed, but the safe wouldn't
+respond so, the change would be discarded. This improves upon the algorithm by
+removing the locked tumbler from the pool of tumblers to randomly change.
+
+"""

From 7eac1bdcba2bde2b47a3c36fa819e7edf45a4c97 Mon Sep 17 00:00:00 2001
From: JoseALermaIII <jose@JoseALerma.com>
Date: Sun, 13 Oct 2019 12:13:26 -0500
Subject: [PATCH 02/14] Add compare

---
 src/ch07/c2_safe_cracker.py | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/src/ch07/c2_safe_cracker.py b/src/ch07/c2_safe_cracker.py
index 05df8f1..6e17b4d 100644
--- a/src/ch07/c2_safe_cracker.py
+++ b/src/ch07/c2_safe_cracker.py
@@ -9,3 +9,20 @@
 removing the locked tumbler from the pool of tumblers to randomly change.
 
 """
+
+
+def compare(combo: list, attempt: list) -> int:
+    """Compare items in two lists and count number of matches.
+
+    Compare each element in **combo** with **attempt** and return
+    the number of matches.
+
+    Args:
+        combo (list): Integers of safe combination.
+        attempt (list): Integers of guessed safe combination.
+
+    Returns:
+        Number of combination matches between **combo** and **attempt**.
+
+    """
+    return sum(1 for i, j in zip(combo, attempt) if i == j)

From 8c62783875a965e1e16492cd51313a188edf0f76 Mon Sep 17 00:00:00 2001
From: JoseALermaIII <jose@JoseALerma.com>
Date: Sun, 13 Oct 2019 12:13:35 -0500
Subject: [PATCH 03/14] Initialize TestSafeCracker with test_compare

---
 tests/test_chapter07.py | 32 ++++++++++++++++++++++++++++++++
 1 file changed, 32 insertions(+)

diff --git a/tests/test_chapter07.py b/tests/test_chapter07.py
index ed6466c..0e758b6 100644
--- a/tests/test_chapter07.py
+++ b/tests/test_chapter07.py
@@ -5,6 +5,7 @@
 from io import StringIO
 
 import src.ch07.c1_breed_rats as breed_rats
+import src.ch07.c2_safe_cracker as safe_cracker
 
 
 class TestBreedRats(unittest.TestCase):
@@ -321,5 +322,36 @@ def test_main(self, mock_stdout, mock_random, mock_time):
         self.assertEqual(mock_stdout.getvalue(), file_data)
 
 
+class TestSafeCracker(unittest.TestCase):
+    """Test Safe Cracker."""
+
+    def test_compare(self):
+        """Test compare."""
+        list1 = [8]
+        list2 = [8]
+        test = safe_cracker.compare(list1, list2)
+        self.assertEqual(test, 1)
+        list1 = [8, 9]
+        list2 = [8]
+        test = safe_cracker.compare(list1, list2)
+        self.assertEqual(test, 1)
+        list1 = [8, 9]
+        list2 = [8, 8]
+        test = safe_cracker.compare(list1, list2)
+        self.assertEqual(test, 1)
+        list1 = [8, 9]
+        list2 = [8, 9]
+        test = safe_cracker.compare(list1, list2)
+        self.assertEqual(test, 2)
+        list1 = [8, 9, 7, 4, 5, 9, 0]
+        list2 = [8, 8, 6, 3, 5, 8, 1]
+        test = safe_cracker.compare(list1, list2)
+        self.assertEqual(test, 2)
+        list1 = [8, 9, 7, 4, 5, 9, 0]
+        list2 = [8, 9, 7, 4, 5, 9, 0]
+        test = safe_cracker.compare(list1, list2)
+        self.assertEqual(test, 7)
+
+
 if __name__ == '__main__':
     unittest.main()

From 630d09449711d2d120aba67a39fd15c189d90ee0 Mon Sep 17 00:00:00 2001
From: JoseALermaIII <jose@JoseALerma.com>
Date: Sun, 13 Oct 2019 14:01:12 -0500
Subject: [PATCH 04/14] Add crack_safe

---
 src/ch07/c2_safe_cracker.py | 46 +++++++++++++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)

diff --git a/src/ch07/c2_safe_cracker.py b/src/ch07/c2_safe_cracker.py
index 6e17b4d..8e1c56a 100644
--- a/src/ch07/c2_safe_cracker.py
+++ b/src/ch07/c2_safe_cracker.py
@@ -9,6 +9,7 @@
 removing the locked tumbler from the pool of tumblers to randomly change.
 
 """
+import random
 
 
 def compare(combo: list, attempt: list) -> int:
@@ -26,3 +27,48 @@ def compare(combo: list, attempt: list) -> int:
 
     """
     return sum(1 for i, j in zip(combo, attempt) if i == j)
+
+
+def crack_safe(combo: str) -> tuple:
+    """Crack a safe combination with a hill-climbing algorithm.
+
+    Solve a lock combination by randomly changing a tumbler's values one
+    by one and noting whether the safe had a response. If so, lock the
+    tumbler at that value, remove it from the pool of tumblers, and
+    continue randomly changing tumbler values.
+
+    Args:
+        combo (str): String of numbers representing combination of safe.
+
+    Returns:
+        Tuple with string of solved combination and number of attempts.
+
+    """
+    # Convert combo to list.
+    combo = [int(i) for i in combo]
+
+    # Make initial guess and compare.
+    best_guess = [0] * len(combo)
+    best_guess_match = compare(combo, best_guess)
+
+    count = 0
+    tumblers = list(range(len(combo)))
+
+    # Evolve guess.
+    while best_guess != combo:
+        # Crossover.
+        guess = best_guess.copy()
+
+        # Mutate.
+        lock_tumbler = random.choice(tumblers)
+        guess[lock_tumbler] = random.randint(0, len(combo) - 1)
+
+        # Compare and select.
+        guess_match = compare(combo, guess)
+        if guess_match > best_guess_match:
+            best_guess = guess.copy()
+            best_guess_match = guess_match
+            tumblers.remove(lock_tumbler)
+        print(guess, best_guess)
+        count += 1
+    return ''.join([str(i) for i in best_guess]), count

From 8cc9c7a3888b16896ad2b677c256c8702c19c0f3 Mon Sep 17 00:00:00 2001
From: JoseALermaIII <jose@JoseALerma.com>
Date: Sun, 13 Oct 2019 14:01:41 -0500
Subject: [PATCH 05/14] Initial commit

---
 tests/data/ch07/safe_cracker.txt | 110 +++++++++++++++++++++++++++++++
 1 file changed, 110 insertions(+)
 create mode 100644 tests/data/ch07/safe_cracker.txt

diff --git a/tests/data/ch07/safe_cracker.txt b/tests/data/ch07/safe_cracker.txt
new file mode 100644
index 0000000..fe5fcd3
--- /dev/null
+++ b/tests/data/ch07/safe_cracker.txt
@@ -0,0 +1,110 @@
+[0, 0, 0, 0, 0, 0, 0, 0, 0, 5] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 0, 0, 0, 0, 0, 0, 0] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 0, 0, 8, 0, 0, 0, 0] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 0, 0, 0, 0, 0, 0, 5] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 0, 0, 0, 0, 0, 0, 9] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 6, 0, 0, 0, 0, 0, 0, 0] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 0, 0, 0, 9, 0, 0, 0] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 0, 0, 0, 0, 0, 0, 2] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 0, 0, 2, 0, 0, 0, 0] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 0, 0, 0, 0, 0, 3, 0] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 0, 0, 8, 0, 0, 0, 0] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 7, 0, 0, 0, 0, 0, 0] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 9, 0, 0, 0, 0, 0, 0, 0] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 2, 0, 0, 0, 0, 0, 0] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 0, 0, 0, 0, 8, 0, 0] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 0, 0, 0, 0, 0, 0, 1] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 0, 0, 0, 5, 0, 0, 0] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 1, 0, 0, 0, 0, 0, 0] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 6, 0, 0, 0, 0, 0, 0] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 0, 0, 0, 0, 6, 0, 0] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 4, 0, 0, 0, 0, 0, 0, 0, 0] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 0, 0, 0, 0, 0, 0, 0] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 0, 8, 0, 0, 0, 0, 0] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 4, 0, 0, 0, 0, 0, 0] [0, 0, 0, 4, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 4, 9, 0, 0, 0, 0, 0] [0, 0, 0, 4, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 4, 0, 0, 0, 4, 0, 0] [0, 0, 0, 4, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 4, 0, 0, 0, 0, 0, 0] [0, 0, 0, 4, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 4, 0, 8, 0, 0, 0, 0] [0, 0, 0, 4, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 4, 0, 0, 0, 5, 0, 0] [0, 0, 0, 4, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 4, 0, 0, 0, 0, 3, 0] [0, 0, 0, 4, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 4, 0, 4, 0, 0, 0, 0] [0, 0, 0, 4, 0, 0, 0, 0, 0, 0]
+[0, 0, 5, 4, 0, 0, 0, 0, 0, 0] [0, 0, 0, 4, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 4, 0, 0, 0, 0, 6, 0] [0, 0, 0, 4, 0, 0, 0, 0, 0, 0]
+[0, 7, 0, 4, 0, 0, 0, 0, 0, 0] [0, 0, 0, 4, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 4, 9, 0, 0, 0, 0, 0] [0, 0, 0, 4, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 4, 0, 0, 0, 0, 0, 3] [0, 0, 0, 4, 0, 0, 0, 0, 0, 3]
+[0, 0, 0, 4, 0, 0, 1, 0, 0, 3] [0, 0, 0, 4, 0, 0, 0, 0, 0, 3]
+[0, 0, 0, 4, 0, 0, 0, 0, 0, 3] [0, 0, 0, 4, 0, 0, 0, 0, 0, 3]
+[0, 0, 0, 4, 0, 0, 6, 0, 0, 3] [0, 0, 0, 4, 0, 0, 0, 0, 0, 3]
+[0, 0, 0, 4, 0, 0, 8, 0, 0, 3] [0, 0, 0, 4, 0, 0, 0, 0, 0, 3]
+[0, 0, 0, 4, 0, 3, 0, 0, 0, 3] [0, 0, 0, 4, 0, 0, 0, 0, 0, 3]
+[0, 0, 0, 4, 0, 0, 9, 0, 0, 3] [0, 0, 0, 4, 0, 0, 0, 0, 0, 3]
+[0, 0, 0, 4, 0, 1, 0, 0, 0, 3] [0, 0, 0, 4, 0, 0, 0, 0, 0, 3]
+[0, 0, 0, 4, 0, 0, 0, 0, 0, 3] [0, 0, 0, 4, 0, 0, 0, 0, 0, 3]
+[8, 0, 0, 4, 0, 0, 0, 0, 0, 3] [8, 0, 0, 4, 0, 0, 0, 0, 0, 3]
+[8, 0, 0, 4, 0, 0, 0, 3, 0, 3] [8, 0, 0, 4, 0, 0, 0, 0, 0, 3]
+[8, 0, 0, 4, 0, 9, 0, 0, 0, 3] [8, 0, 0, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 0, 4, 0, 9, 4, 0, 0, 3] [8, 0, 0, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 4, 4, 0, 9, 0, 0, 0, 3] [8, 0, 0, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 0, 4, 0, 9, 0, 0, 0, 3] [8, 0, 0, 4, 0, 9, 0, 0, 0, 3]
+[8, 2, 0, 4, 0, 9, 0, 0, 0, 3] [8, 0, 0, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 3, 4, 0, 9, 0, 0, 0, 3] [8, 0, 0, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 8, 4, 0, 9, 0, 0, 0, 3] [8, 0, 0, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 0, 4, 0, 9, 2, 0, 0, 3] [8, 0, 0, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 0, 4, 0, 9, 8, 0, 0, 3] [8, 0, 0, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 0, 4, 8, 9, 0, 0, 0, 3] [8, 0, 0, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 0, 4, 0, 9, 5, 0, 0, 3] [8, 0, 0, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 0, 4, 9, 9, 0, 0, 0, 3] [8, 0, 0, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 0, 4, 8, 9, 0, 0, 0, 3] [8, 0, 0, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 0, 4, 0, 9, 0, 0, 0, 3] [8, 0, 0, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 0, 4, 0, 9, 0, 0, 8, 3] [8, 0, 0, 4, 0, 9, 0, 0, 0, 3]
+[8, 2, 0, 4, 0, 9, 0, 0, 0, 3] [8, 0, 0, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 0, 4, 6, 9, 0, 0, 0, 3] [8, 0, 0, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 0, 4, 4, 9, 0, 0, 0, 3] [8, 0, 0, 4, 0, 9, 0, 0, 0, 3]
+[8, 4, 0, 4, 0, 9, 0, 0, 0, 3] [8, 0, 0, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 0, 4, 0, 9, 9, 0, 0, 3] [8, 0, 0, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 7, 4, 0, 9, 0, 0, 0, 3] [8, 0, 7, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 7, 4, 0, 9, 0, 0, 7, 3] [8, 0, 7, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 7, 4, 2, 9, 0, 0, 0, 3] [8, 0, 7, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 7, 4, 0, 9, 0, 0, 7, 3] [8, 0, 7, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 7, 4, 0, 9, 0, 9, 0, 3] [8, 0, 7, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 7, 4, 0, 9, 2, 0, 0, 3] [8, 0, 7, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 7, 4, 0, 9, 0, 0, 0, 3] [8, 0, 7, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 7, 4, 0, 9, 4, 0, 0, 3] [8, 0, 7, 4, 0, 9, 0, 0, 0, 3]
+[8, 0, 7, 4, 0, 9, 0, 2, 0, 3] [8, 0, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 2, 7, 4, 0, 9, 0, 2, 0, 3] [8, 0, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 4, 7, 4, 0, 9, 0, 2, 0, 3] [8, 0, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 0, 7, 4, 0, 9, 8, 2, 0, 3] [8, 0, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 2, 7, 4, 0, 9, 0, 2, 0, 3] [8, 0, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 9, 7, 4, 0, 9, 0, 2, 0, 3] [8, 9, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 9, 7, 4, 7, 9, 0, 2, 0, 3] [8, 9, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 9, 7, 4, 7, 9, 0, 2, 0, 3] [8, 9, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 9, 7, 4, 2, 9, 0, 2, 0, 3] [8, 9, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 9, 7, 4, 0, 9, 0, 2, 7, 3] [8, 9, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 9, 7, 4, 0, 9, 3, 2, 0, 3] [8, 9, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 9, 7, 4, 0, 9, 0, 2, 4, 3] [8, 9, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 9, 7, 4, 3, 9, 0, 2, 0, 3] [8, 9, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 9, 7, 4, 0, 9, 7, 2, 0, 3] [8, 9, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 9, 7, 4, 0, 9, 0, 2, 6, 3] [8, 9, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 9, 7, 4, 0, 9, 0, 2, 0, 3] [8, 9, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 9, 7, 4, 0, 9, 0, 2, 0, 3] [8, 9, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 9, 7, 4, 0, 9, 7, 2, 0, 3] [8, 9, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 9, 7, 4, 0, 9, 0, 2, 9, 3] [8, 9, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 9, 7, 4, 0, 9, 0, 2, 0, 3] [8, 9, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 9, 7, 4, 0, 9, 3, 2, 0, 3] [8, 9, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 9, 7, 4, 0, 9, 0, 2, 0, 3] [8, 9, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 9, 7, 4, 0, 9, 0, 2, 0, 3] [8, 9, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 9, 7, 4, 0, 9, 0, 2, 3, 3] [8, 9, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 9, 7, 4, 8, 9, 0, 2, 0, 3] [8, 9, 7, 4, 0, 9, 0, 2, 0, 3]
+[8, 9, 7, 4, 0, 9, 0, 2, 1, 3] [8, 9, 7, 4, 0, 9, 0, 2, 1, 3]
+[8, 9, 7, 4, 9, 9, 0, 2, 1, 3] [8, 9, 7, 4, 0, 9, 0, 2, 1, 3]
+[8, 9, 7, 4, 0, 9, 9, 2, 1, 3] [8, 9, 7, 4, 0, 9, 0, 2, 1, 3]
+[8, 9, 7, 4, 0, 9, 5, 2, 1, 3] [8, 9, 7, 4, 0, 9, 0, 2, 1, 3]
+[8, 9, 7, 4, 3, 9, 0, 2, 1, 3] [8, 9, 7, 4, 0, 9, 0, 2, 1, 3]
+[8, 9, 7, 4, 7, 9, 0, 2, 1, 3] [8, 9, 7, 4, 0, 9, 0, 2, 1, 3]
+[8, 9, 7, 4, 4, 9, 0, 2, 1, 3] [8, 9, 7, 4, 0, 9, 0, 2, 1, 3]
+[8, 9, 7, 4, 0, 9, 6, 2, 1, 3] [8, 9, 7, 4, 0, 9, 0, 2, 1, 3]
+[8, 9, 7, 4, 0, 9, 0, 2, 1, 3] [8, 9, 7, 4, 0, 9, 0, 2, 1, 3]
+[8, 9, 7, 4, 0, 9, 4, 2, 1, 3] [8, 9, 7, 4, 0, 9, 0, 2, 1, 3]
+[8, 9, 7, 4, 5, 9, 0, 2, 1, 3] [8, 9, 7, 4, 5, 9, 0, 2, 1, 3]

From c4607b932cd37f1296644b6df1ddf3d8215f86d9 Mon Sep 17 00:00:00 2001
From: JoseALermaIII <jose@JoseALerma.com>
Date: Sun, 13 Oct 2019 14:02:06 -0500
Subject: [PATCH 06/14] Add setUpClass to TestSafeCracker

---
 tests/test_chapter07.py | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/tests/test_chapter07.py b/tests/test_chapter07.py
index 0e758b6..8a9596d 100644
--- a/tests/test_chapter07.py
+++ b/tests/test_chapter07.py
@@ -325,6 +325,11 @@ def test_main(self, mock_stdout, mock_random, mock_time):
 class TestSafeCracker(unittest.TestCase):
     """Test Safe Cracker."""
 
+    @classmethod
+    def setUpClass(cls):
+        """Configure attributes for use in this class only."""
+        cls.random = Random()
+
     def test_compare(self):
         """Test compare."""
         list1 = [8]

From c49098ea3f7e3c690d0e7cd37a35d38805662561 Mon Sep 17 00:00:00 2001
From: JoseALermaIII <jose@JoseALerma.com>
Date: Sun, 13 Oct 2019 14:02:35 -0500
Subject: [PATCH 07/14] Add test_crack_safe to TestSafeCracker

---
 tests/test_chapter07.py | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/tests/test_chapter07.py b/tests/test_chapter07.py
index 8a9596d..ed1ad0e 100644
--- a/tests/test_chapter07.py
+++ b/tests/test_chapter07.py
@@ -357,6 +357,26 @@ def test_compare(self):
         test = safe_cracker.compare(list1, list2)
         self.assertEqual(test, 7)
 
+    @unittest.mock.patch('src.ch07.c2_safe_cracker.random')
+    @unittest.mock.patch('sys.stdout', new_callable=StringIO)
+    def test_crack_safe(self, mock_stdout, mock_random):
+        """Test crack_safe."""
+        # Patch random to use non-random seed.
+        self.random.seed(211)
+        mock_random.choice._mock_side_effect = self.random.choice
+        mock_random.randint._mock_side_effect = self.random.randint
+
+        combo = '8974590213'
+        test, count = safe_cracker.crack_safe(combo)
+        self.assertEqual(count, 110)
+        self.assertEqual(combo, test)
+
+        # Test sys.stdout output.
+        with open(os.path.normpath('tests/data/ch07/safe_cracker.txt'),
+                  'r') as file:
+            file_data = ''.join(file.readlines())
+        self.assertEqual(mock_stdout.getvalue(), file_data)
+
 
 if __name__ == '__main__':
     unittest.main()

From c2127bdc5e1d6eeb8e9b56081d6dae30364925b3 Mon Sep 17 00:00:00 2001
From: JoseALermaIII <jose@JoseALerma.com>
Date: Sun, 13 Oct 2019 14:09:51 -0500
Subject: [PATCH 08/14] Fix punctuation in module docstring

---
 src/ch07/c2_safe_cracker.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/ch07/c2_safe_cracker.py b/src/ch07/c2_safe_cracker.py
index 8e1c56a..babd8fd 100644
--- a/src/ch07/c2_safe_cracker.py
+++ b/src/ch07/c2_safe_cracker.py
@@ -5,7 +5,7 @@
 tumbler at that value and continue randomly changing tumbler values.
 
 Previously, a locked tumbler can still be changed, but the safe wouldn't
-respond so, the change would be discarded. This improves upon the algorithm by
+respond, so the change would be discarded. This improves upon the algorithm by
 removing the locked tumbler from the pool of tumblers to randomly change.
 
 """

From c9ae13da7230b0f93f26ed08286400c78c93d5c5 Mon Sep 17 00:00:00 2001
From: JoseALermaIII <jose@JoseALerma.com>
Date: Sun, 13 Oct 2019 14:10:02 -0500
Subject: [PATCH 09/14] Add main

---
 src/ch07/c2_safe_cracker.py | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/src/ch07/c2_safe_cracker.py b/src/ch07/c2_safe_cracker.py
index babd8fd..402b97d 100644
--- a/src/ch07/c2_safe_cracker.py
+++ b/src/ch07/c2_safe_cracker.py
@@ -9,6 +9,7 @@
 removing the locked tumbler from the pool of tumblers to randomly change.
 
 """
+import time
 import random
 
 
@@ -72,3 +73,27 @@ def crack_safe(combo: str) -> tuple:
         print(guess, best_guess)
         count += 1
     return ''.join([str(i) for i in best_guess]), count
+
+
+def main():
+    """Demonstrate safe cracker.
+
+    Use default combination to demonstrate :func:`crack_safe` and display time
+    (in seconds) it took to run.
+
+    """
+    start_time = time.time()
+
+    combination = '6822858902'
+    print(f'Combination: {combination}')
+    guess, count = crack_safe(combination)
+    print(f'\nCracked! {guess} ')
+    print(f'in {count} tries!')
+
+    end_time = time.time()
+    duration = end_time - start_time
+    print(f'\nRuntime for this program was {duration:.5f} seconds.')
+
+
+if __name__ == '__main__':
+    main()

From 97df86ba7eef0936c0248dbea55afcf687c46f86 Mon Sep 17 00:00:00 2001
From: JoseALermaIII <jose@JoseALerma.com>
Date: Sun, 13 Oct 2019 14:14:21 -0500
Subject: [PATCH 10/14] Initial commit

---
 tests/data/ch07/main/safe_cracker.txt | 127 ++++++++++++++++++++++++++
 1 file changed, 127 insertions(+)
 create mode 100644 tests/data/ch07/main/safe_cracker.txt

diff --git a/tests/data/ch07/main/safe_cracker.txt b/tests/data/ch07/main/safe_cracker.txt
new file mode 100644
index 0000000..01a80a1
--- /dev/null
+++ b/tests/data/ch07/main/safe_cracker.txt
@@ -0,0 +1,127 @@
+Combination: 6822858902
+[0, 0, 0, 5, 0, 0, 0, 0, 0, 0] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 0, 0, 0, 0, 3, 0, 0] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 0, 0, 0, 6, 0, 0, 0] [0, 0, 0, 0, 0, 0, 0, 0, 0, 0]
+[0, 0, 0, 0, 0, 0, 0, 0, 0, 2] [0, 0, 0, 0, 0, 0, 0, 0, 0, 2]
+[0, 0, 0, 6, 0, 0, 0, 0, 0, 2] [0, 0, 0, 0, 0, 0, 0, 0, 0, 2]
+[0, 0, 0, 0, 0, 0, 0, 0, 3, 2] [0, 0, 0, 0, 0, 0, 0, 0, 0, 2]
+[0, 0, 7, 0, 0, 0, 0, 0, 0, 2] [0, 0, 0, 0, 0, 0, 0, 0, 0, 2]
+[0, 0, 0, 0, 0, 0, 6, 0, 0, 2] [0, 0, 0, 0, 0, 0, 0, 0, 0, 2]
+[0, 0, 0, 0, 6, 0, 0, 0, 0, 2] [0, 0, 0, 0, 0, 0, 0, 0, 0, 2]
+[0, 0, 0, 5, 0, 0, 0, 0, 0, 2] [0, 0, 0, 0, 0, 0, 0, 0, 0, 2]
+[0, 0, 0, 0, 0, 0, 0, 0, 0, 2] [0, 0, 0, 0, 0, 0, 0, 0, 0, 2]
+[0, 0, 0, 0, 0, 3, 0, 0, 0, 2] [0, 0, 0, 0, 0, 0, 0, 0, 0, 2]
+[0, 0, 0, 0, 0, 0, 0, 6, 0, 2] [0, 0, 0, 0, 0, 0, 0, 0, 0, 2]
+[0, 6, 0, 0, 0, 0, 0, 0, 0, 2] [0, 0, 0, 0, 0, 0, 0, 0, 0, 2]
+[0, 0, 0, 0, 0, 0, 0, 0, 1, 2] [0, 0, 0, 0, 0, 0, 0, 0, 0, 2]
+[0, 0, 0, 0, 1, 0, 0, 0, 0, 2] [0, 0, 0, 0, 0, 0, 0, 0, 0, 2]
+[0, 0, 0, 0, 0, 7, 0, 0, 0, 2] [0, 0, 0, 0, 0, 0, 0, 0, 0, 2]
+[0, 0, 0, 5, 0, 0, 0, 0, 0, 2] [0, 0, 0, 0, 0, 0, 0, 0, 0, 2]
+[0, 0, 0, 8, 0, 0, 0, 0, 0, 2] [0, 0, 0, 0, 0, 0, 0, 0, 0, 2]
+[0, 0, 0, 0, 0, 0, 0, 0, 0, 2] [0, 0, 0, 0, 0, 0, 0, 0, 0, 2]
+[0, 0, 0, 0, 0, 0, 8, 0, 0, 2] [0, 0, 0, 0, 0, 0, 8, 0, 0, 2]
+[0, 0, 0, 0, 7, 0, 8, 0, 0, 2] [0, 0, 0, 0, 0, 0, 8, 0, 0, 2]
+[0, 0, 0, 0, 0, 0, 8, 0, 7, 2] [0, 0, 0, 0, 0, 0, 8, 0, 0, 2]
+[0, 9, 0, 0, 0, 0, 8, 0, 0, 2] [0, 0, 0, 0, 0, 0, 8, 0, 0, 2]
+[0, 0, 0, 0, 0, 0, 8, 0, 0, 2] [0, 0, 0, 0, 0, 0, 8, 0, 0, 2]
+[0, 0, 7, 0, 0, 0, 8, 0, 0, 2] [0, 0, 0, 0, 0, 0, 8, 0, 0, 2]
+[0, 0, 0, 0, 0, 0, 8, 0, 8, 2] [0, 0, 0, 0, 0, 0, 8, 0, 0, 2]
+[5, 0, 0, 0, 0, 0, 8, 0, 0, 2] [0, 0, 0, 0, 0, 0, 8, 0, 0, 2]
+[0, 0, 0, 7, 0, 0, 8, 0, 0, 2] [0, 0, 0, 0, 0, 0, 8, 0, 0, 2]
+[0, 0, 2, 0, 0, 0, 8, 0, 0, 2] [0, 0, 2, 0, 0, 0, 8, 0, 0, 2]
+[0, 0, 2, 0, 0, 8, 8, 0, 0, 2] [0, 0, 2, 0, 0, 0, 8, 0, 0, 2]
+[0, 0, 2, 0, 9, 0, 8, 0, 0, 2] [0, 0, 2, 0, 0, 0, 8, 0, 0, 2]
+[0, 0, 2, 0, 0, 0, 8, 9, 0, 2] [0, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[0, 0, 2, 0, 0, 0, 8, 9, 0, 2] [0, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[0, 0, 2, 0, 0, 9, 8, 9, 0, 2] [0, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[0, 0, 2, 0, 0, 0, 8, 9, 3, 2] [0, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[0, 2, 2, 0, 0, 0, 8, 9, 0, 2] [0, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[0, 0, 2, 0, 0, 9, 8, 9, 0, 2] [0, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[0, 0, 2, 0, 0, 0, 8, 9, 4, 2] [0, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[0, 0, 2, 0, 0, 0, 8, 9, 0, 2] [0, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[0, 0, 2, 0, 0, 0, 8, 9, 0, 2] [0, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[0, 0, 2, 1, 0, 0, 8, 9, 0, 2] [0, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[0, 0, 2, 0, 0, 1, 8, 9, 0, 2] [0, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[0, 0, 2, 0, 5, 0, 8, 9, 0, 2] [0, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[0, 3, 2, 0, 0, 0, 8, 9, 0, 2] [0, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[0, 0, 2, 0, 0, 9, 8, 9, 0, 2] [0, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[0, 0, 2, 0, 1, 0, 8, 9, 0, 2] [0, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[0, 0, 2, 0, 0, 6, 8, 9, 0, 2] [0, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[0, 0, 2, 0, 3, 0, 8, 9, 0, 2] [0, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[0, 0, 2, 0, 0, 0, 8, 9, 1, 2] [0, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[0, 0, 2, 4, 0, 0, 8, 9, 0, 2] [0, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[6, 0, 2, 0, 0, 0, 8, 9, 0, 2] [6, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[6, 0, 2, 3, 0, 0, 8, 9, 0, 2] [6, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[6, 7, 2, 0, 0, 0, 8, 9, 0, 2] [6, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[6, 0, 2, 0, 0, 4, 8, 9, 0, 2] [6, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[6, 0, 2, 0, 0, 0, 8, 9, 0, 2] [6, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[6, 0, 2, 3, 0, 0, 8, 9, 0, 2] [6, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[6, 0, 2, 0, 0, 9, 8, 9, 0, 2] [6, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[6, 0, 2, 0, 0, 0, 8, 9, 0, 2] [6, 0, 2, 0, 0, 0, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 0, 8, 9, 0, 2] [6, 8, 2, 0, 0, 0, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 4, 8, 9, 0, 2] [6, 8, 2, 0, 0, 0, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 3, 8, 9, 0, 2] [6, 8, 2, 0, 0, 0, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 5, 8, 9, 0, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 6, 0, 5, 8, 9, 0, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 4, 5, 8, 9, 0, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 5, 8, 9, 8, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 6, 0, 5, 8, 9, 0, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 5, 8, 9, 9, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 5, 8, 9, 5, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 5, 8, 9, 6, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 6, 0, 5, 8, 9, 0, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 5, 8, 9, 8, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 9, 0, 5, 8, 9, 0, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 5, 8, 9, 4, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 5, 8, 9, 0, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 5, 8, 9, 3, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 5, 8, 9, 7, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 5, 8, 9, 1, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 5, 8, 9, 9, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 4, 5, 8, 9, 0, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 5, 8, 9, 9, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 5, 8, 9, 3, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 5, 0, 5, 8, 9, 0, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 5, 8, 9, 0, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 2, 5, 8, 9, 0, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 5, 8, 9, 4, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 5, 8, 9, 8, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 5, 8, 9, 1, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 5, 8, 9, 9, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 5, 8, 9, 0, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 5, 5, 8, 9, 0, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 4, 5, 8, 9, 0, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 4, 5, 8, 9, 0, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 5, 8, 9, 1, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 0, 5, 8, 9, 0, 2] [6, 8, 2, 0, 0, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 8, 5, 8, 9, 0, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 3, 8, 5, 8, 9, 0, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 8, 5, 8, 9, 8, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 8, 5, 8, 9, 9, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 4, 8, 5, 8, 9, 0, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 8, 5, 8, 9, 0, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 8, 8, 5, 8, 9, 0, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 6, 8, 5, 8, 9, 0, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 8, 5, 8, 9, 3, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 4, 8, 5, 8, 9, 0, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 6, 8, 5, 8, 9, 0, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 8, 5, 8, 9, 6, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 8, 8, 5, 8, 9, 0, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 8, 5, 8, 9, 7, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 8, 8, 5, 8, 9, 0, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 8, 5, 8, 9, 7, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 8, 5, 8, 9, 7, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 8, 5, 8, 9, 3, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 7, 8, 5, 8, 9, 0, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 7, 8, 5, 8, 9, 0, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 8, 5, 8, 9, 7, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 4, 8, 5, 8, 9, 0, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 8, 5, 8, 9, 4, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 8, 5, 8, 9, 6, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 0, 8, 5, 8, 9, 6, 2] [6, 8, 2, 0, 8, 5, 8, 9, 0, 2]
+[6, 8, 2, 2, 8, 5, 8, 9, 0, 2] [6, 8, 2, 2, 8, 5, 8, 9, 0, 2]
+
+Cracked! 6822858902 
+in 121 tries!
+
+Runtime for this program was 55545.00000 seconds.

From 87155a71d1657960e149b1c9c6e839a481f5bf6d Mon Sep 17 00:00:00 2001
From: JoseALermaIII <jose@JoseALerma.com>
Date: Sun, 13 Oct 2019 14:14:38 -0500
Subject: [PATCH 11/14] Add test_main to TestSafeCracker

---
 tests/test_chapter07.py | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/tests/test_chapter07.py b/tests/test_chapter07.py
index ed1ad0e..169476a 100644
--- a/tests/test_chapter07.py
+++ b/tests/test_chapter07.py
@@ -377,6 +377,25 @@ def test_crack_safe(self, mock_stdout, mock_random):
             file_data = ''.join(file.readlines())
         self.assertEqual(mock_stdout.getvalue(), file_data)
 
+    @unittest.mock.patch('src.ch07.c2_safe_cracker.time')
+    @unittest.mock.patch('src.ch07.c2_safe_cracker.random')
+    @unittest.mock.patch('sys.stdout', new_callable=StringIO)
+    def test_main(self, mock_stdout, mock_random, mock_time):
+        """Test main."""
+        # Patch out variances.
+        self.random.seed(111)
+        mock_random.choice._mock_side_effect = self.random.choice
+        mock_random.randint._mock_side_effect = self.random.randint
+        mock_time.time.side_effect = [12345, 67890]
+
+        safe_cracker.main()
+
+        # Test sys.stdout output.
+        with open(os.path.normpath('tests/data/ch07/main/safe_cracker.txt'),
+                  'r') as file:
+            file_data = ''.join(file.readlines())
+        self.assertEqual(mock_stdout.getvalue(), file_data)
+
 
 if __name__ == '__main__':
     unittest.main()

From 238eb19db8f0bbb54f5f3c8b66a0bf202c5d2df1 Mon Sep 17 00:00:00 2001
From: JoseALermaIII <jose@JoseALerma.com>
Date: Sun, 13 Oct 2019 14:15:24 -0500
Subject: [PATCH 12/14] Add c2_safe_cracker

---
 docs/source/src.ch07.rst | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/docs/source/src.ch07.rst b/docs/source/src.ch07.rst
index 6885a5b..3801c32 100644
--- a/docs/source/src.ch07.rst
+++ b/docs/source/src.ch07.rst
@@ -12,6 +12,14 @@ src.ch07.c1\_breed\_rats module
    :undoc-members:
    :show-inheritance:
 
+src.ch07.c2\_safe\_cracker module
+---------------------------------
+
+.. automodule:: src.ch07.c2_safe_cracker
+   :members:
+   :undoc-members:
+   :show-inheritance:
+
 
 Module contents
 ---------------

From 65b4757a34d517c38309affec4748e84f915760c Mon Sep 17 00:00:00 2001
From: JoseALermaIII <jose@JoseALerma.com>
Date: Sun, 13 Oct 2019 14:46:11 -0500
Subject: [PATCH 13/14] [skip ci] Reword compare docstring

---
 src/ch07/c2_safe_cracker.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/ch07/c2_safe_cracker.py b/src/ch07/c2_safe_cracker.py
index 402b97d..d1ec9a3 100644
--- a/src/ch07/c2_safe_cracker.py
+++ b/src/ch07/c2_safe_cracker.py
@@ -16,7 +16,7 @@
 def compare(combo: list, attempt: list) -> int:
     """Compare items in two lists and count number of matches.
 
-    Compare each element in **combo** with **attempt** and return
+    Compare each tumbler in **combo** with **attempt** and return
     the number of matches.
 
     Args:
@@ -24,7 +24,7 @@ def compare(combo: list, attempt: list) -> int:
         attempt (list): Integers of guessed safe combination.
 
     Returns:
-        Number of combination matches between **combo** and **attempt**.
+        Number of tumbler matches between **combo** and **attempt**.
 
     """
     return sum(1 for i, j in zip(combo, attempt) if i == j)

From e7acfc8bc68e99c9bd8ea2869adbb4848eb89c5d Mon Sep 17 00:00:00 2001
From: JoseALermaIII <jose@JoseALerma.com>
Date: Sun, 13 Oct 2019 14:46:11 -0500
Subject: [PATCH 14/14] Reword compare docstring

---
 src/ch07/c2_safe_cracker.py | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/ch07/c2_safe_cracker.py b/src/ch07/c2_safe_cracker.py
index 402b97d..d1ec9a3 100644
--- a/src/ch07/c2_safe_cracker.py
+++ b/src/ch07/c2_safe_cracker.py
@@ -16,7 +16,7 @@
 def compare(combo: list, attempt: list) -> int:
     """Compare items in two lists and count number of matches.
 
-    Compare each element in **combo** with **attempt** and return
+    Compare each tumbler in **combo** with **attempt** and return
     the number of matches.
 
     Args:
@@ -24,7 +24,7 @@ def compare(combo: list, attempt: list) -> int:
         attempt (list): Integers of guessed safe combination.
 
     Returns:
-        Number of combination matches between **combo** and **attempt**.
+        Number of tumbler matches between **combo** and **attempt**.
 
     """
     return sum(1 for i, j in zip(combo, attempt) if i == j)