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Building Instances

Instances are Plain Ol’ Ruby Objects and the attributes are attached with getters and setters with their values assigned to the value return from their block at build time.

To build an object:

result = FakerMaker[:basket].build

will generate a new instance using the Basket factory. Because an actual class is defined, you can instantiate an object directly through but that will not populate any of the attributes.

It’s possible to override attributes at build-time, either by passing values as a hash:

result = FakerMaker[:item].build( name: 'Electric Blanket' )

or by passing in a block:

result = FakerMaker[:item].build{ |i| = 'Electric Sheep' }

this is particularly useful for overriding nested values, since all the getters and setters of the embedded objects are already constructed:

result = FakerMaker[:basket].build do |b| = 'Neon Badger'

if you’re crazy enough to want to do both styles during creation, the values in the block will be preserved, e.g.

result = FakerMaker[:item].build( name: 'Electric Blanket' ) do |i| = 'Electric Sheep'

then the value of is ‘Electric Sheep’.

Beware when overriding values in this way: there is no type checking. You will get an exception if you try to set a value to an attribute that doesn’t exist but you won’t get one if you assign, say, an array of values where you would otherwise have a string and vice versa.

Calling result.to_json will give a stringified JSON representation. Because ActiveSupport is used under the covers, as_json will give you a Hash rather than the stringified version.

As a convenience, you can request a JSON representation directly:

result = FakerMaker[:basket].to_json

As another convenience, FakerMaker is also assigned to the variable FM to it is possible to write just:

result = FM[:basket].build

Copyright © 2019-2020 Nigel Brookes-Thomas. Distributed by an MIT license.