implement exercise resistor-color (exercism#1680) (exercism#1686)

closes exercism#1680

Author: gabriel376

config.json

@@ -1534,6 +1534,16 @@
       "difficulty": 0,
       "topics": null,
       "deprecated": true
+    },
+    {
+      "slug": "resistor-color",
+      "uuid": "d17bee9c-e803-4745-85ea-864f255fb04e",
+      "core": false,
+      "unlocked_by": null,
+      "difficulty": 1,
+      "topics": [
+        "arrays"
+      ]
     }
   ]
 }

exercises/resistor-color/README.md

@@ -0,0 +1,70 @@
+# Resistor Color
+
+Resistors have color coded bands, where each color maps to a number. The first 2 bands of a resistor have a simple encoding scheme: each color maps to a single number.
+
+These colors are encoded as follows:
+
+- Black: 0
+- Brown: 1
+- Red: 2
+- Orange: 3
+- Yellow: 4
+- Green: 5
+- Blue: 6
+- Violet: 7
+- Grey: 8
+- White: 9
+
+Mnemonics map the colors to the numbers, that, when stored as an array, happen to map to their index in the array: Better Be Right Or Your Great Big Values Go Wrong.
+
+More information on the color encoding of resistors can be found in the [Electronic color code Wikipedia article](https://en.wikipedia.org/wiki/Electronic_color_code)
+
+
+## Exception messages
+
+Sometimes it is necessary to raise an exception. When you do this, you should include a meaningful error message to
+indicate what the source of the error is. This makes your code more readable and helps significantly with debugging. Not
+every exercise will require you to raise an exception, but for those that do, the tests will only pass if you include
+a message.
+
+To raise a message with an exception, just write it as an argument to the exception type. For example, instead of
+`raise Exception`, you should write:
+
+```python
+raise Exception("Meaningful message indicating the source of the error")
+```
+
+## Running the tests
+
+To run the tests, run the appropriate command below ([why they are different](https://github.com/pytest-dev/pytest/issues/1629#issue-161422224)):
+
+- Python 2.7: `py.test resistor_color_test.py`
+- Python 3.4+: `pytest resistor_color_test.py`
+
+Alternatively, you can tell Python to run the pytest module (allowing the same command to be used regardless of Python version):
+`python -m pytest resistor_color_test.py`
+
+### Common `pytest` options
+
+- `-v` : enable verbose output
+- `-x` : stop running tests on first failure
+- `--ff` : run failures from previous test before running other test cases
+
+For other options, see `python -m pytest -h`
+
+## Submitting Exercises
+
+Note that, when trying to submit an exercise, make sure the solution is in the `$EXERCISM_WORKSPACE/python/resistor-color` directory.
+
+You can find your Exercism workspace by running `exercism debug` and looking for the line that starts with `Workspace`.
+
+For more detailed information about running tests, code style and linting,
+please see [Running the Tests](http://exercism.io/tracks/python/tests).
+
+## Source
+
+Maud de Vries, Erik Schierboom [https://github.com/exercism/problem-specifications/issues/1458](https://github.com/exercism/problem-specifications/issues/1458)
+
+## Submitting Incomplete Solutions
+
+It's possible to submit an incomplete solution so you can see how others have completed the exercise.

exercises/resistor-color/example.py

@@ -0,0 +1,20 @@
+COLORS = [
+    'black',
+    'brown',
+    'red',
+    'orange',
+    'yellow',
+    'green',
+    'blue',
+    'violet',
+    'grey',
+    'white'
+]
+
+
+def color_code(color):
+    return COLORS.index(color)
+
+
+def colors():
+    return COLORS

exercises/resistor-color/resistor_color.py

@@ -0,0 +1,6 @@
+def color_code(color):
+    pass
+
+
+def colors():
+    pass

exercises/resistor-color/resistor_color_test.py

@@ -0,0 +1,35 @@
+import unittest
+
+from resistor_color import color_code, colors
+
+
+# Tests adapted from `problem-specifications//canonical-data.json` @ v1.0.0
+
+class ResistorColorTest(unittest.TestCase):
+    def test_black(self):
+        self.assertEqual(color_code('black'), 0)
+
+    def test_white(self):
+        self.assertEqual(color_code('white'), 9)
+
+    def test_orange(self):
+        self.assertEqual(color_code('orange'), 3)
+
+    def test_colors(self):
+        expected = [
+            'black',
+            'brown',
+            'red',
+            'orange',
+            'yellow',
+            'green',
+            'blue',
+            'violet',
+            'grey',
+            'white'
+        ]
+        self.assertEqual(colors(), expected)
+
+
+if __name__ == '__main__':
+    unittest.main()