Investigate why certain requests result in an error or incorrect response

[rkazakov]

Investigate why certain requests result in an error or incorrect response.

Request: http://localhost:4000/api/v1/Gen1-2
Response: message: "Bible passage is not found."

Request: http://localhost:4000/api/v1/Gen1-3
Response: Chapters 1 and 3 are missing!

Request: http://localhost:4000/api/v1/Gen1-4
Response: Chapters 1 and 4 are missing!

Please, develop tests to catch this kind of problems.

[rkazakov]

The bug that caused requests to fail was fixed in 98ea026.
@romaduck Please add unit tests.