#!/usr/bin/env python
# coding: utf-8

# This notebook was prepared by [Donne Martin](https://github.com/donnemartin). Source and license info is on [GitHub](https://github.com/donnemartin/interactive-coding-challenges).

# # Challenge Notebook

# ## Problem: Sort an array of strings so all anagrams are next to each other.
# 
# * [Constraints](#Constraints)
# * [Test Cases](#Test-Cases)
# * [Algorithm](#Algorithm)
# * [Code](#Code)
# * [Unit Test](#Unit-Test)
# * [Solution Notebook](#Solution-Notebook)

# ## Constraints
# 
# * Are there any other sorting requirements other than the grouping of anagrams?
#     * No
# * Can we assume the inputs are valid?
#     * No
# * Can we assume this fits memory?
#     * Yes

# ## Test Cases
# 
# * None -> Exception
# * [] -> []
# * General case
#     * Input: ['ram', 'act', 'arm', 'bat', 'cat', 'tab']
#     * Result: ['arm', 'ram', 'act', 'cat', 'bat', 'tab']

# ## Algorithm
# 
# Refer to the [Solution Notebook](http://nbviewer.jupyter.org/github/donnemartin/interactive-coding-challenges/blob/master/sorting_searching/anagrams/anagrams_solution.ipynb).  If you are stuck and need a hint, the solution notebook's algorithm discussion might be a good place to start.

# ## Code

# In[ ]:


from collections import OrderedDict


class Anagram(object):

    def group_anagrams(self, items):
        # TODO: Implement me
        pass


# ## Unit Test

# **The following unit test is expected to fail until you solve the challenge.**

# In[ ]:


# %load test_anagrams.py
import unittest


class TestAnagrams(unittest.TestCase):

    def test_group_anagrams(self):
        anagram = Anagram()
        self.assertRaises(TypeError, anagram.group_anagrams, None)
        data = ['ram', 'act', 'arm', 'bat', 'cat', 'tab']
        expected = ['ram', 'arm', 'act', 'cat', 'bat', 'tab']
        self.assertEqual(anagram.group_anagrams(data), expected)

        print('Success: test_group_anagrams')


def main():
    test = TestAnagrams()
    test.test_group_anagrams()


if __name__ == '__main__':
    main()


# ## Solution Notebook
# 
# Review the [Solution Notebook]() for a discussion on algorithms and code solutions.