fails:String#to_c returns a Complex object
fails:String#to_c understands integers
fails:String#to_c understands negative integers
fails:String#to_c understands fractions (numerator/denominator) for the real part
fails:String#to_c understands fractions (numerator/denominator) for the imaginary part
fails:String#to_c understands negative fractions (-numerator/denominator) for the real part
fails:String#to_c understands negative fractions (-numerator/denominator) for the imaginary part
fails:String#to_c understands floats (a.b) for the real part
fails:String#to_c understands floats (a.b) for the imaginary part
fails:String#to_c understands negative floats (-a.b) for the real part
fails:String#to_c understands negative floats (-a.b) for the imaginary part
fails:String#to_c understands an integer followed by 'i' to mean that integer is the imaginary part
fails:String#to_c understands a negative integer followed by 'i' to mean that negative integer is the imaginary part
fails:String#to_c understands an 'i' by itself as denoting a complex number with an imaginary part of 1
fails:String#to_c understands a '-i' by itself as denoting a complex number with an imaginary part of -1
fails:String#to_c understands 'a+bi' to mean a complex number with 'a' as the real part, 'b' as the imaginary
fails:String#to_c understands 'a-bi' to mean a complex number with 'a' as the real part, '-b' as the imaginary
fails:String#to_c understands scientific notation for the real part
fails:String#to_c understands negative scientific notation for the real part
fails:String#to_c understands scientific notation for the imaginary part
fails:String#to_c understands negative scientific notation for the imaginary part
fails:String#to_c understands scientific notation for the real and imaginary part in the same String
fails:String#to_c understands negative scientific notation for the real and imaginary part in the same String
fails:String#to_c returns a complex number with 0 as the real part, 0 as the imaginary part for unrecognised Strings
