[UTILS] Unit Testing Framework

TL;DR

• This script doesn't provide any buy/sell signals.
  
• This script won't make you profitable implicitly.
  
• This script is intended for utility function testing, library testing, custom assertions.
  
• It is free and open-source.
  

Introduction
About the idea: is not exclusive, programmers tend to use this method a lot and for a long time.
The point is to ensure that parts of a software, "units" (i.e modules, functions, procedures, class methods etc), work as they should, meet they design and behave as intended. That's why we use the term "Unit testing".
In PineScript we don't have a lot of entities mentioned above yet. What we have are functions. For example, a function that sums numbers should return a number, a particular sum. Or a professor wrote a function that calculates something or whatever. He and you want to be sure that the function works as expected and further code changes (refactoring) won't break its behaviour. What the professor needs to do is to write unit tests for his function/library of functions. And what you need to do is to check if the professor wrote tests or not.

No tests = No code
- Total test-driven development

Ok, it is not so serious, but very important in software development. And I created a tool for that.
I tried to follow the APIs of testing tools/libs/frameworks I worked or work with: Jasmine (Javascript), Mocha/Chai (Javascript), Jest (Javascript), RSpec (Ruby), unittest (Python), pytest (Python) and others. Got something workable but it would be much easier to implement (and it would look much better) if PineScript had a higher-order functions feature.

API

_describe(suiteName: string)
A function to declare a test suite. Each suite with tests may have 2 statuses:

• ✔️ Passed
  
• ❌ Failed
  

A suite is considered to be failed if at least one of the specs in it has failed.

_it(specName: string, actual: any, expected: any)
A function to run a test. Each test may have 3 statuses:

• ✔️ Passed
  
• ❌ Failed
  
• ⛔ Skipped
  

Some examples:

• _it("is a falsey value", 1 != 2, true)
  
• _it("is not a number", na(something), true)
  
• _it("should sum two integers", _sum(1, 2), 1)
  
• _it("arrays are equal", _isEqual(array.from(1, 2), array.from(1, 2)), true)
  

Remember that both the 'actual' and 'expected' arguments must be of the same type.
And a group of _it() functions must be preceded by a _describe() declaration (see in the code).

_test(specName: string, actual: any, expected: any)
An alias for _it. Does the same thing.

_xit(specName: string, actual: any, expected: any)
A function to skip a particular test for a while. Doesn't make any comparisons, but the test will appear in the results as skipped.
This feature is unstable and may be removed in the future releases.

_xtest(specName: string, actual: any, expected: any)
An alias for _xit. Does the same thing.

_isEqual(id_1: array<any>, id_2: array<any>)
A function to compare two arrays for equality. Both arrays must be of the same type.
This function doesn't take into account the order of elements in each array. So arrays like (1, 2, 3) and (3, 2, 1) will be equal.

_isStrictEqual(id_1: array<any>, id_2: array<any>)
A function to compare two arrays for equality. Both arrays must be of the same type.
This function is a stricter version of _isEqual because it takes into account the order of elements in each array. So arrays like (1, 2, 3) and (3, 2, 1) won't be equal.

Usage

To use this script to test your library you need to do the following steps:
1) Copy all the code you see between line #5 and #282 (Unit Testing Framework Core)
2) Place the copied code at the very beginning of your script (but below study())
3) Start to write suites and tests where your code ends. That's it.

NOTE

The current version is 0.0.1 which means that a lot of things may be changed on the way to 1.0.0 - the first stable version.

Note di rilascio:

• Version 0.0.2
  
• Moved global variables inside a reporter function
  
• Minor optimizations
  

Note di rilascio:

• Version 1.0.0
  
• Migrated to PineScript V5