Fixes 905, fix: Use full path of Result type + unit test

[anstylian]

this pull request contains 3 commits:

1. add cmake and ninja in the flake: Was needed to run cargo test from the test directory
2. unit-test added to replicate issue: Replicates the error described in issue Type error regression when using enum called Result #905 in a unit-test
3. fix: Use full path of Result type: Fixes issue Type error regression when using enum called Result #905