Travis CI: Add a flake8 test for unused imports (#1038)

.travis.yml

@@ -6,7 +6,7 @@ before_install: pip install --upgrade pip setuptools
 install: pip install -r requirements.txt
 before_script:
   - black --check . || true
-  - flake8 . --count --select=E9,F63,F7,F82 --show-source --statistics
+  - flake8 . --count --select=E9,F401,F63,F7,F82 --show-source --statistics
 script:
   - mypy --ignore-missing-imports .
   - pytest . --doctest-modules

graphs/bfs.py

@@ -16,10 +16,19 @@ while Q is non-empty:
 
 """
 
-import collections
+G = {'A': ['B', 'C'],
+     'B': ['A', 'D', 'E'],
+     'C': ['A', 'F'],
+     'D': ['B'],
+     'E': ['B', 'F'],
+     'F': ['C', 'E']}
 
 
 def bfs(graph, start):
+    """
+    >>> ''.join(sorted(bfs(G, 'A')))
+    'ABCDEF'
+    """
     explored, queue = set(), [start]  # collections.deque([start])
     explored.add(start)
     while queue:
@@ -31,11 +40,5 @@ def bfs(graph, start):
     return explored
 
 
-G = {'A': ['B', 'C'],
-     'B': ['A', 'D', 'E'],
-     'C': ['A', 'F'],
-     'D': ['B'],
-     'E': ['B', 'F'],
-     'F': ['C', 'E']}
-
+if __name__ == '__main__':
     print(bfs(G, 'A'))

maths/volume.py

@@ -6,8 +6,6 @@ Wikipedia reference: https://en.wikipedia.org/wiki/Volume
 
 from math import pi
 
-PI = pi
-
 
 def vol_cube(side_length):
     """Calculate the Volume of a Cube."""
@@ -39,9 +37,7 @@ def vol_right_circ_cone(radius, height):
     volume = (1/3) * pi * radius^2 * height
     """
 
-    import math
-
-    return (float(1) / 3) * PI * (radius ** 2) * height
+    return (float(1) / 3) * pi * (radius ** 2) * height
 
 
 def vol_prism(area_of_base, height):
@@ -71,7 +67,7 @@ def vol_sphere(radius):
     V = (4/3) * pi * r^3
     Wikipedia reference: https://en.wikipedia.org/wiki/Sphere
     """
-    return (float(4) / 3) * PI * radius ** 3
+    return (float(4) / 3) * pi * radius ** 3
 
 
 def vol_circular_cylinder(radius, height):
@@ -80,7 +76,7 @@ def vol_circular_cylinder(radius, height):
     Wikipedia reference: https://en.wikipedia.org/wiki/Cylinder
     volume = pi * radius^2 * height
     """
-    return PI * radius ** 2 * height
+    return pi * radius ** 2 * height
 
 
 def main():

other/primelib.py

@@ -39,12 +39,14 @@ goldbach(number)  // Goldbach's assumption
 
 """
 
+from math import sqrt
+
+
 def isPrime(number):
     """
         input: positive integer 'number'
         returns true if 'number' is prime otherwise false.
     """
-    import math # for function sqrt
 
     # precondition
     assert isinstance(number,int) and (number >= 0) , \
@@ -56,7 +58,7 @@ def isPrime(number):
     if number <= 1:
         status = False
 
-    for divisor in range(2,int(round(math.sqrt(number)))+1):
+    for divisor in range(2,int(round(sqrt(number)))+1):
 
         # if 'number' divisible by 'divisor' then sets 'status'
         # of false and break up the loop.
@@ -143,8 +145,6 @@ def primeFactorization(number):
         returns a list of the prime number factors of 'number'
     """
 
-    import math    # for function sqrt
-    
     # precondition
     assert isinstance(number,int) and number >= 0, \
     "'number' must been an int and >= 0"
@@ -497,8 +497,6 @@ def getDivisors(n):
     # precondition
     assert isinstance(n,int) and (n >= 1), "'n' must been int and >= 1"
 
-    from math import sqrt        
-        
     ans = [] # will be returned.
 
     for divisor in range(1,n+1):

project_euler/problem_13/sol1.py

@@ -3,18 +3,12 @@ Problem Statement:
 Work out the first ten digits of the sum of the following one-hundred 50-digit
 numbers.
 """
-from __future__ import print_function
-import os
-
-try:
-    raw_input  # Python 2
-except NameError:
-    raw_input = input  # Python 3
 
 
 def solution(array):
     """Returns the first ten digits of the sum of the array elements.
 
+    >>> import os
     >>> sum = 0
     >>> array = []
     >>> with open(os.path.dirname(__file__) + "/num.txt","r") as f: