Isogram: Exercise for isogram with test cases.

An isogram (also known as a "nonpattern word") is a word or phrase without a repeating letter.

Examples of isograms:

    -lumberjacks
    -background
    -downstream
The word isograms, however, is not an isogram, because the s repeats.

Author: sbulage

config.json

@@ -64,9 +64,16 @@
     "poker",
     "zebra-puzzle",
     "rectangles",
-    "binary-search"
+    "binary-search",
+    "isogram"
   ],
   "exercises": [
+    {
+      "slug": "isogram",
+      "difficulty": 1,
+      "topics": [
+      ]
+    },
     {
       "slug": "hello-world",
       "difficulty": 1,

exercises/isogram/example.py

@@ -0,0 +1,3 @@
+def isogram(string):
+    string = string.lower()
+    return len(set(string)) == len(string)

exercises/isogram/isogram_test.py

@@ -0,0 +1,20 @@
+import unittest
+from example import isogram
+
+
+class TestIsogram(unittest.TestCase):
+
+    def test_isogram(self):
+        tests = ['lumberjacks', 'background', 'downstream']
+        for test in tests:
+            string = isogram(test)
+            self.assertTrue(string, True)
+
+    def test_isogram_false(self):
+        tests = ['isograms', 'aba', '  ']
+        for test in tests:
+            string = isogram(test)
+            self.assertFalse(string, False)
+
+if __name__ == '__main__':
+    unittest.main()