'float' coercion tests

Add tests for 'float' coercion function.
Common numeric coercion function

Alter 'int' coercion function to handle either 'int' or 'float'. The
'expected_type' argument is used for this function. Rename this
function to 'coerce_numeric_input'.

Assign 'coerce_numeric_input' to both 'int' and 'float' types.

All tests pass.