Missing sample and fixed tests for

• Singular rating input

• Output requiring ordinal indicators to be 11th, 12th, 13th, 111th etc.

• Description does not explicitly mention how to handle ordinal indicators and the expected upper bounds. But based on current test cases, it should not exceed 20.

• should also be language-agnostic

The example strongly implies that empty slots should be filled with 'undefined' but the solution reveals empty slots are to remain empty. Description should state "Empty slots are to remain empty".

D translation

• Rust translation
• Go translation

It should be mentioned how high numbers will be tested. For python it's only up to 100 (why not higher?), IDK about others.

Contents for random tests are wrong (in JS at least)... The cards do not contain a name property as specified in the description.

All cards, regardless of deck, have a name property, which does not have a rating and cannot be played.

Example of random card: { vxlzzekyJinnxlswfzUkktpteuYcku: 51, ytunXripbiry: 99, norktctrwFjcc: 41, irrtkXvlfh: 28, jnktvmznwkrMdigyiHmpdBzjvpn: 97, vvzbfGsqhzsCbdkEfutfisl: 2 }

Why grouped[4] = null? Why not grouped[4] = []? That way, all elements of your result would be arrays.