The general solutions for built-ins (for example test) are ^[1]:

• use env (all shells)

   $ env test
   external test
  

• disable the builtin (only bash and zsh):

   $ test 1 = 1 && echo "yes"
   yes
   $ enable -n test        ### for bash. Re-enable with "enable test".
   $ disable test          ### for zsh. Re-enable with "enable test".
   $ test
   external test
  

• use any slash / to call the command (all shells):

   $ test 1 = 1 && echo "yes"
   yes 
   $ ~/bin/test
   external test
  

• make an alias (fails inside a bash script, except if shopt -s expand_aliases is used):

   $ alias test='~/bin/test'             ### remove with 'unalias test'.
   $ test
   external test
  

But time is not a builtin.

The word time is a "Reserved word", not a command and neither a built-in. That enable this solutions:

• Quote the word. This does not work with built-ins.
  Many forms of quoting work: \time "time" 'time' ti\me ti"me", etc.

   $  time
  
   real    0m0.000s
   user    0m0.000s
   sys     0m0.000s
  
   $ \time
   Usage: /usr/bin/time [-apvV] [-f format] [-o file] [--append] [--verbose]
          [--portability] [--format=format] [--output=file] [--version]
          [--quiet] [--help] command [arg...]
  

• Use the builtin command (this does not work with built-ins):

   $ command time
  

• As above for built-ins, using any slash / works:

   $ /usr/bin/time
  

• As above for built-ins, an alias also work here:

   $ alias time='command time'
   $ alias time='/usr/bin/time'
  

^{[1] Lets assume there is an external executable in ~/bin/test that prints "external test". And further: lets assume that ~/bin is ahead of /bin in the active PATH.}

The general solutions for built-ins (for example test) are ^[1]:

• use env (all shells)

   $ env test
   external test
  

• disable the builtin (only bash and zsh):

   $ test 1 = 1 && echo "yes"
   yes
   $ enable -n test        ### for bash. Re-enable with "enable test".
   $ disable test          ### for zsh. Re-enable with "enable test".
   $ test
   external test
  

• use any slash / to call the command (all shells):

   $ test 1 = 1 && echo "yes"
   yes 
   $ ~/bin/test
   external test
  

• make an alias (fails inside a bash script, except if shopt -s expand_aliases is used):

   $ alias test='~/bin/test'             ### remove with 'unalias test'.
   $ test
   external test
  

But time is not a builtin.

The word time is a "Reserved word", not a command and neither a built-in. That enable this solutions:

• Quote the word. This does not work with built-ins.
  Many forms of quoting work: \time "time" 'time' ti\me ti"me", etc.

   $  time
  
   real    0m0.000s
   user    0m0.000s
   sys     0m0.000s
  
   $ \time
   Usage: /usr/bin/time [-apvV] [-f format] [-o file] [--append] [--verbose]
          [--portability] [--format=format] [--output=file] [--version]
          [--quiet] [--help] command [arg...]
  

This is useful to bypass an alias. Even if test is aliased, \test will execute the PATHed command (or the builtin if it has not been disabled).

• Use the builtin command (this does not work with built-ins):

   $ command time
  

• As above for built-ins, using any slash / works:

   $ /usr/bin/time
  

• As above for built-ins, an alias also work here:

   $ alias time='command time'
   $ alias time='/usr/bin/time'
  

^{[1] Lets assume there is an external executable in ~/bin/test that prints "external test". And further: lets assume that ~/bin is ahead of /bin in the active PATH.}