Here is a quick and easy way to quick test your config. You can also use C-x C-e at the end of specific lisp to execute certain function individually.
C-x C-e runs the command eval-last-sexp (found in global-map), which is an interactive compiled Lisp function.
It is bound to C-x C-e.
(eval-last-sexp EVAL-LAST-SEXP-ARG-INTERNAL)
Evaluate sexp before point; print value in the echo area. Interactively, with prefix argument, print output into current buffer.
Normally, this function truncates long output according to the value of the variables ‘eval-expression-print-length’ and ‘eval-expression-print-level’. With a prefix argument of zero, however, there is no such truncation. Such a prefix argument also causes integers to be printed in several additional formats (octal, hexadecimal, and character).
If ‘eval-expression-debug-on-error’ is non-nil, which is the default, this command arranges for all errors to enter the debugger.