issue224 fix

checks a more specific edge case for substitution, that of a single
mixed-case duplicate

Author: patrickthornton

substitution/__init__.py

@@ -17,55 +17,78 @@ def compiles():
 @check50.check(compiles)
 def encrypt1():
     """encrypts "A" as "Z" using ZYXWVUTSRQPONMLKJIHGFEDCBA as key"""
-    check50.run("./substitution ZYXWVUTSRQPONMLKJIHGFEDCBA").stdin("A").stdout("ciphertext:\s*Z\n", "ciphertext: Z\n").exit(0)
+    check50.run("./substitution ZYXWVUTSRQPONMLKJIHGFEDCBA").stdin("A").stdout(
+        "ciphertext:\s*Z\n", "ciphertext: Z\n"
+    ).exit(0)
 
 
 @check50.check(compiles)
 def encrypt2():
     """encrypts "a" as "z" using ZYXWVUTSRQPONMLKJIHGFEDCBA as key"""
-    check50.run("./substitution ZYXWVUTSRQPONMLKJIHGFEDCBA").stdin("a").stdout("ciphertext:\s*z\n", "ciphertext: z\n").exit(0)
+    check50.run("./substitution ZYXWVUTSRQPONMLKJIHGFEDCBA").stdin("a").stdout(
+        "ciphertext:\s*z\n", "ciphertext: z\n"
+    ).exit(0)
 
 
 @check50.check(compiles)
 def encrypt3():
     """encrypts "ABC" as "NJQ" using NJQSUYBRXMOPFTHZVAWCGILKED as key"""
-    check50.run("./substitution NJQSUYBRXMOPFTHZVAWCGILKED").stdin("ABC").stdout("ciphertext:\s*NJQ\n", "ciphertext: NJQ\n").exit(0)
+    check50.run("./substitution NJQSUYBRXMOPFTHZVAWCGILKED").stdin("ABC").stdout(
+        "ciphertext:\s*NJQ\n", "ciphertext: NJQ\n"
+    ).exit(0)
 
 
 @check50.check(compiles)
 def encrypt4():
     """encrypts "XyZ" as "KeD" using NJQSUYBRXMOPFTHZVAWCGILKED as key"""
-    check50.run("./substitution NJQSUYBRXMOPFTHZVAWCGILKED").stdin("XyZ").stdout("ciphertext:\s*KeD\n", "ciphertext: KeD\n").exit(0)
+    check50.run("./substitution NJQSUYBRXMOPFTHZVAWCGILKED").stdin("XyZ").stdout(
+        "ciphertext:\s*KeD\n", "ciphertext: KeD\n"
+    ).exit(0)
 
 
 @check50.check(compiles)
 def encrypt5():
     """encrypts "This is CS50" as "Cbah ah KH50" using YUKFRNLBAVMWZTEOGXHCIPJSQD as key"""
-    check50.run("./substitution YUKFRNLBAVMWZTEOGXHCIPJSQD").stdin("This is CS50").stdout("ciphertext:\s*Cbah ah KH50\n", "ciphertext: Cbah ah KH50\n").exit(0)
+    check50.run("./substitution YUKFRNLBAVMWZTEOGXHCIPJSQD").stdin(
+        "This is CS50"
+    ).stdout("ciphertext:\s*Cbah ah KH50\n", "ciphertext: Cbah ah KH50\n").exit(0)
 
 
 @check50.check(compiles)
 def encrypt6():
     """encrypts "This is CS50" as "Cbah ah KH50" using yukfrnlbavmwzteogxhcipjsqd as key"""
-    check50.run("./substitution yukfrnlbavmwzteogxhcipjsqd").stdin("This is CS50").stdout("ciphertext:\s*Cbah ah KH50\n", "ciphertext: Cbah ah KH50\n").exit(0)
+    check50.run("./substitution yukfrnlbavmwzteogxhcipjsqd").stdin(
+        "This is CS50"
+    ).stdout("ciphertext:\s*Cbah ah KH50\n", "ciphertext: Cbah ah KH50\n").exit(0)
 
 
 @check50.check(compiles)
 def encrypt7():
     """encrypts "This is CS50" as "Cbah ah KH50" using YUKFRNLBAVMWZteogxhcipjsqd as key"""
-    check50.run("./substitution YUKFRNLBAVMWZteogxhcipjsqd").stdin("This is CS50").stdout("ciphertext:\s*Cbah ah KH50\n", "ciphertext: Cbah ah KH50\n").exit(0)
+    check50.run("./substitution YUKFRNLBAVMWZteogxhcipjsqd").stdin(
+        "This is CS50"
+    ).stdout("ciphertext:\s*Cbah ah KH50\n", "ciphertext: Cbah ah KH50\n").exit(0)
 
 
 @check50.check(compiles)
 def encrypt8():
     """encrypts all alphabetic characters using DWUSXNPQKEGCZFJBTLYROHIAVM as key"""
-    check50.run("./substitution DWUSXNPQKEGCZFJBTLYROHIAVM").stdin("The quick brown fox jumps over the lazy dog").stdout("ciphertext:\s*Rqx tokug wljif nja eozby jhxl rqx cdmv sjp\n", "ciphertext: Rqx tokug wljif nja eozby jhxl rqx cdmv sjp\n").exit(0)
+    check50.run("./substitution DWUSXNPQKEGCZFJBTLYROHIAVM").stdin(
+        "The quick brown fox jumps over the lazy dog"
+    ).stdout(
+        "ciphertext:\s*Rqx tokug wljif nja eozby jhxl rqx cdmv sjp\n",
+        "ciphertext: Rqx tokug wljif nja eozby jhxl rqx cdmv sjp\n",
+    ).exit(0)
 
 
 @check50.check(compiles)
 def encrypt9():
     """does not encrypt non-alphabetical characters using DWUSXNPQKEGCZFJBTLYROHIAVM as key"""
-    check50.run("./substitution DWUSXNPQKEGCZFJBTLYROHIAVM").stdin("Shh... Don't tell!").stdout("ciphertext:\s*Yqq... Sjf'r rxcc!\n", "ciphertext: Yqq... Sjf'r rxcc!\n").exit(0)
+    check50.run("./substitution DWUSXNPQKEGCZFJBTLYROHIAVM").stdin(
+        "Shh... Don't tell!"
+    ).stdout(
+        "ciphertext:\s*Yqq... Sjf'r rxcc!\n", "ciphertext: Yqq... Sjf'r rxcc!\n"
+    ).exit(0)
 
 
 @check50.check(compiles)
@@ -108,3 +131,9 @@ def handles_duplicate_chars_lower():
 def handles_multiple_duplicate_chars():
     """handles multiple duplicate characters in key"""
     check50.run("./substitution MMCcEFGHIJKLMNOPqRqTUVWXeZ").exit(1)
+
+
+@check50.check(compiles)
+def handles_single_duplicate_character():
+    """handles a single mixed-case duplicate character in key"""
+    check50.run("./substitution ABCDEFGHIJKLMNOPpQRSTUVWXY").exit(1)