Coding Challenge

Write code to find the longest word in a file as well as the reversed representation of the longest word found. Create test cases to verify that the longest word (normal and reversed) is found.

Assumptions

Input file

The file content is a valid JSON representation of the form:
```
{
    "lowercase_letters": {
        "given_input": "a ab abc abcd abcdefg",
        "expected_output": "abcdefg",
        "expected_output_transposed": "gfedcba"
    },
    "numbers": {
        "given_input": "1324 12 3 0 1325 23 341 13410158 1235 12 1",
        "expected_output": "13410158",
        "expected_output_transposed": "85101431"
    }
}
```
Why not using a regular file with contents such as:
```
a
ab
abc
abcdefg
```
Because this limits test case reuse. If we want to run the same test with different data we will need to create separate input files for each scenario we want to cover. Also, for each newly created file we will need to open the file, read it, store the contents in a string and finally close it. Since we are storing the contents in a string; Why not pass a string in the first place? This problem seems like a good candidate for a Data Driven Test approach.

Why Data Driven Test?

This allows us to implement an approach where the same test is used with different data. Did I mentioned that adding new tests is also easier and more readable?
Two or more words with the same size

The last longest word found is returned if there are 2 or more words with the same size.
Words

Words are strings. If the input given is not a string then we return the empty string as the longest word.

Requirements

Run tests

Open a terminal/prompt
Run git clone https://github.com/jllopez/coding_challenge.git to fetch the projects code
Run cd coding_challenge to change to the project's root directory
Run python3 -m virtualenv env to create a virtual environment
Run source env/bin/activate to activate the virtual environment
Run pip install -r requirements.txt
Run python test_longest_word_finder.py

If everything was setup correctly an output similar to this should be displayed in the terminal:

Running tests...
----------------------------------------------------------------------
..............
----------------------------------------------------------------------
Ran 14 tests in 0.001s

OK

Generating XML reports...

In addition, an XML file with test results can be found under ./test_results

Want to run the test file with your own data?

Running the test file with your own data is easy. All you have to do is add a new entry to input_file.json.

For example,

If you want to check what is the longest word in which word is the loooooooongest one here? all you have to do is add the following entry at the end of the dictionary in input_file.json:

"my_new_test": {
"given_input": "which word is the loooooooongest one here?",
"expected_output": "loooooooongest",
"expected_output_transposed": "tsegnooooooool"
}

Don't forget to add a comma after the last existing entry and before your new one:

},
"my_new_test": {
"given_input": "which word is the loooooooongest one here?",
"expected_output": "loooooooongest",
"expected_output_transposed": "tsegnooooooool"
}

Otherwise, a ValueError exception is raised indicating the JSON representation is invalid.

jllopez/tdd_example

Coding Challenge

Assumptions

Requirements

Run tests

Want to run the test file with your own data?