Add Int#bit_length #8924
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Add Int#bit_length #8924
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RX14
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Mar 21, 2020
vlazar
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Mar 21, 2020
Co-Authored-By: Vladislav Zarakovsky <vlad.zar@gmail.com>
RX14
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Mar 21, 2020
oprypin
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Mar 21, 2020
spec/std/int_spec.cr
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| it "#bit_length" do | ||
| 0.bit_length.should eq(0) | ||
| (1..100).each do |i| | ||
| i.bit_length.should eq(Math.log2(i).to_i + 1) |
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This is testing that the result of bit_length matches some mathematical formula. But it has about as much to do with the expected answers as the actual implementation of the method. Should you then have to write tests for this mathematical formula?
Tests shouldn't have logic, I'd suggest checking actual inputs.
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Things like 0b1000 and 0b111.bit_length might look nice
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Nice, thanks. But I think it still needs some checks specifically with "1+all-zeros" (like 0b1000) and "all-ones" (0b111) to catch off-by-one errors.
RX14
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straight-shoota
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vlazar
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RX14
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carlhoerberg
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Apr 29, 2020
* Add Int#bit_length * Update src/int.cr Co-Authored-By: Vladislav Zarakovsky <vlad.zar@gmail.com> * Simpler Int#bit_length specs * Spec for Int#bit_length negative values * Let Int#bit_length work for BigInt * More specs... * Be nice with Windows Co-authored-by: Vladislav Zarakovsky <vlad.zar@gmail.com>
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Will be useful to implement https://forum.crystal-lang.org/t/integer-sqrt-in-stdlib . It's probably also a generally useful method. Also available in Ruby.