Travis CI: Run black, doctest, flake8, mypy, and pytest

.travis.yml

@@ -1,5 +1,33 @@
 language: python
 dist: xenial  # required for Python >= 3.7
 python: 3.7
-install: pip install flake8
-script: flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
+cache: pip
+install: pip install black flake8 mypy pytest
+before_script:
+  - black --check . || true
+  - flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
+  # - python -m doctest -v other/detecting_english_programmatically.py
+  - python -m doctest
+      ciphers/affine_cipher.py
+      ciphers/brute_force_caesar_cipher.py
+      ciphers/transposition_cipher.py
+      other/frequency_finder.py
+      searches/binary_search.py
+      searches/linear_search.py
+      searches/sentinel_linear_search.py
+      sorts/bogo_sort.py
+      sorts/comb_sort.py
+      sorts/counting_sort.py
+      sorts/heap_sort.py
+      sorts/insertion_sort.py
+      sorts/merge_sort.py
+      sorts/quick_sort.py
+      sorts/selection_sort.py
+      sorts/shell_sort.py
+      strings/levenshtein_distance.py
+script:
+  - mypy --ignore-missing-imports .
+  - pytest || true
+after_success:
+  - python ./~script.py
+  - cat DIRECTORY.md

other/detecting_english_programmatically.py

@@ -6,7 +6,7 @@
 def loadDictionary():
     path = os.path.split(os.path.realpath(__file__))
     englishWords = {}
-    with open(path[0] + '/Dictionary.txt') as dictionaryFile:
+    with open(path[0] + '/dictionary.txt') as dictionaryFile:
         for word in dictionaryFile.read().split('\n'):
             englishWords[word] = None
     return englishWords