Iterative fibonacci with unittests from slash (#882)

* iterative and formula fibonacci methods

Added two ways to calculate the fibonacci sequence:  (1) iterative  (2) formula.  

I've also added a timer decorator so someone can see the difference in computation time between these two methods.  

Added two unittests using the slash framework.

* Update test_fibonacci.py

* remove inline comments per Contributing Guidelines

* Update sol5.py

* Create placeholder.py

* Update and rename maths/test_fibonacci.py to maths/tests/test_fibonacci.py

* Delete placeholder.py

* Create __init__.py

* Update test_fibonacci.py

* Rename Maths/lucasSeries.py to maths/lucasSeries.py

* Update and rename Project Euler/Problem 01/sol5.py to project_euler/problem_01/sol6.py

maths/tests/test_fibonacci.py

@@ -0,0 +1,34 @@
+"""
+To run with slash:
+1. run pip install slash (may need to install C++ builds from Visual Studio website)
+2. In the command prompt navigate to your project folder
+3. then type--> slash run -vv -k tags:fibonacci ..
+    -vv indicates the level of verbosity (how much stuff you want the test to spit out after running)
+    -k is a way to select the tests you want to run.  This becomes much more important in large scale projects.
+"""
+
+import slash
+from .. import fibonacci
+
+default_fib = [0, 1, 1, 2, 3, 5, 8]
+
+
+@slash.tag('fibonacci')
+@slash.parametrize(('n', 'seq'), [(2, [0, 1]), (3, [0, 1, 1]), (9, [0, 1, 1, 2, 3, 5, 8, 13, 21])])
+def test_different_sequence_lengths(n, seq):
+    """Test output of varying fibonacci sequence lengths"""
+    iterative = fibonacci.fib_iterative(n)
+    formula = fibonacci.fib_formula(n)
+    assert iterative == seq
+    assert formula == seq
+
+
+@slash.tag('fibonacci')
+@slash.parametrize('n', [7.3, 7.8, 7.0])
+def test_float_input_iterative(n):
+    """Test when user enters a float value"""
+    iterative = fibonacci.fib_iterative(n)
+    formula = fibonacci.fib_formula(n)
+    assert iterative == default_fib
+    assert formula == default_fib
+