What I meant here is that inputs like .52 and 6. are considered valid, which is not immediately obvious. Output of course should be formatted to a well-formed format.

The tests now also check for leading/trailing zeros and the code also trims them.

Thank you, it should be fixed now. Let me know if something else must be changed, this is my first kata :)

You have to take into consideration that the output format must be X.X where X is a number.

Random tests often expects incorrectly formatted numbers, such as 032. -> 032.0 and .470590 -> 0.470590.

In fact, there are no considerion about integers and leading/trailing zeroes, so the results can barely be called a decimal number: we don't normally express them as something like 000005.500000 instead of 5.5. (Trailing .0 on integer values is debatable as well.) Or rather, the title should be changed: Double is a very different beast from decimal number.

It is not specified what is considered a valid decimal number. .52 and 6. are somehow considered valid.

Similarly, null handling is required but not specified.

Fixed invalid number case.
Separated nullity, empty String and invalid numbers in different tests.
Made random test execute 50 times instead of 1.

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