Ruby 3.0 should be enabled (Refer this & this for more detail)

Yeah that's very confusing.

Duplicate.

No fixed tests.

It still shows in-place modification.

Fixed, thank you!

Fixed, Thank you!

Don't use Test.expect.

The example in the description is wrong.

Missing tests with cyclic replacements (like Test.assert_equals({a: 1, b: 2}.replace_keys({a: :b, b: :a}), {a: 2, b: 1})). Incorrect solution: https://www.codewars.com/kata/reviews/5e42e6a624428a0001b2cd43/groups/5e42e6a624428a0001b2cd45

Missing tests with falsy values. Incorrect solution: https://www.codewars.com/kata/reviews/5e42e6a624428a0001b2cd43/groups/5e42e88d24428a0001b2cd74

Sample tests:

main.rb:15: syntax error, unexpected ',', expecting &. or :: or '[' or '.'
...equals, hash2.replace_keys(km), { hello: 'there', there: 'is...
...                              ^

This should have been a Suggestion, rather than an Issue, so marking it as resolved.