Issue #16180 has been updated by Hanmac (Hans Mackowiak).


your cases are documented there: https://ruby-doc.org/core-2.6.4/Kernel.html#method-i-rand

`When max.abs is greater than or equal to 1, rand returns a pseudo-random integer greater than or equal to 0 and less than max.to_i.abs.`

`Negative or floating point values for max are allowed, but may give surprising results.`

----------------------------------------
Bug #16180: Random.rand(max) ignores / is broken when max ceiling value is a float
https://bugs.ruby-lang.org/issues/16180#change-81715

* Author: BillyRuffian (Nigel Brookes-Thomas)
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
* ruby -v: ruby 2.6.3p62 (2019-04-16 revision 67580) [x86_64-darwin18]
* Backport: 2.5: UNKNOWN, 2.6: UNKNOWN
----------------------------------------
ruby 2.6.3p62 (2019-04-16 revision 67580) [x86_64-darwin18]
ruby 2.7.0preview1 (2019-05-31 trunk c55db6aa271df4a689dc8eb0039c929bf6ed43ff) [x86_64-darwin18]

Calling `rand` with a float of > 1 always return 0.

Calling `rand` with a float  0 < value > 1 will ignore the ceiling value.

e.g.

```
rand(1.1)
=> 0
rand(1.1)
=> 0
rand(0.5)
=> 0.9501516156613756
rand(0.5)
=> 0.6864252478379304
```



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