Codecov Report

❌ Patch coverage is 73.68421% with 5 lines in your changes missing coverage. Please review.
✅ Project coverage is 86.34%. Comparing base (e5d4fef) to head (6c2e5f9).

@@            Coverage Diff             @@
##           master    #2017      +/-   ##
==========================================
- Coverage   86.36%   86.34%   -0.03%     
==========================================
  Files         146      146              
  Lines        8788     8807      +19     
==========================================
+ Hits         7590     7604      +14     
- Misses       1198     1203       +5     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

I cleaned cf too. I also noticed the parameters are used once now, so their unpacking can be made even simpler.

I added testing against some known simple values. Some more are needed or is this enough?

My code was based on how the rest of cosine.jl looked like. When I saw your corrections the code above started looking suspicious for me and indeed, pdf, cdf and ccdf were type unstable. So I corrected them, though I'm not sure if my solution is optimal.

I'm also not sure about dependencies, but its' easy to change in any case.

@devmotion Could I ask for checking if now it is okay? I am a little unsure about the tests. Is there an instruction somewhere what is the recommended way to write them in Distributions.jl?

@devmotion Good to know that such type inference is not useful. I removed the changes related to this.

Optionally, maybe something like

function pdf(d::Cosine{T}, x::Real) where T<:Real
    z = (x - d.μ) / d.σ
    y = (1 + cospi(z)) / (2d.σ)
    return insupport(d, x) ? y : zero(y)
end

could be considered.

I also added application of build-in functions to test affine transformations and cgf.