Comparison Testing Library

• The comparison library is used by 'is()', 'like()', and 'is_deeply()'
• The Test::Stream::Plugin::Compare plugin is the primary interface
• Does deep structure comparisons
• Very flexible
• Very powerful
• Easy to extend
• Helpful diagnostics

Advanced comparisons

• The '$expect' structure can be simple values or references
• With like() a regex in '$expect' will be used to verify the value in '$got'
• when a tool encounters a custom check it will use it
• Some common check types have shortcuts you can use.

Shortcuts

T()

Check for a True value

F()

Check for a false (but existant) value

D()

Check for a defined value

DNE()

Check that no value exists

FDNE()

Check for either false or DNE

Pattern Matching

match

Check that the value matches the pattern

mismatch

Check that the value does not match the pattern

• 'like()' will convert any regexes into 'match' checks for you.
• 'is()' will compare regexes in their string representation.
• Both will use pattern matching when given a 'match' or 'mismatch' check.

Custom Checks

string

Explicit string compare

number

Explicit number compare

validator

Custom sub as a check

exact_ref

Check for an exact reference

Set Checks

in_set

Check that the value is in the set

not_in_set

Check that the value is not in the set

check_set

Check that the value matches everything in the set

Array Checks

array

Declare an array check

item

Declare an array item

filter_items

Apply a filter to the remaining array items

end

Declare the end of the array

Hash Checks

hash

Declare a hash

field

Declare a hash field

end

Declare that there are no more fields

Meta Checks

meta

Declare a meta check

prop

Declare a meta property to check

Object Checks

object

Declare an object check

call

Declare an object method result

prop

Declare a meta property

field

Declare a hash field (if object is a hash)

item

Declare an array item (if object is an array)

Event Checks

• Used to validate Test::Stream events.
• Has everything object checks do.
• Tells you event generation line numbers.
• Extra meta-checks (line number, file, etc)