无涯教程-RSpec - 元数据

RSpec是一种灵活而强大的工具。RSpec中的元数据(Metadata)函数也不例外。元数据通常指“关于数据的数据”。在RSpec中，这意味着有关您的描述，上下文及其块的数据，让无涯教程看一个例子-

RSpec.describe "An Example Group with a metadata variable", :foo => 17 do 
   context 'and a context with another variable', :bar => 12 do 
      
      it 'can access the metadata variable of the outer Example Group' do |example| 
         expect(example.metadata[:foo]).to eq(17) 
      end
      
      it 'can access the metadata variable in the context block' do |example|  
         expect(example.metadata[:bar]).to eq(12) 
      end 
      
   end 
end

运行上面的代码时，您将看到此输出-

.. 
Finished in 0.002 seconds (files took 0.11301 seconds to load) 
2 examples, 0 failures

元数据提供了一种在RSpec文件中的各个范围内分配变量的方法。 example.metadata变量是Ruby哈希，其中包含有关示例和示例组的其他信息。

例如，重写上面的代码，使其看起来像这样-

RSpec.describe "An Example Group with a metadata variable", :foo => 17 do
   context 'and a context with another variable', :bar => 12 do 
      
      it 'can access the metadata variable in the context block' do |example|
         expect(example.metadata[:foo]).to eq(17) 
         expect(example.metadata[:bar]).to eq(12) 
         example.metadata.each do |k,v|
         puts "#{k}: #{v}"
      end
		
   end 
end 

当运行此代码时，会在example.metadata哈希中看到所有值-

.execution_result: #<RSpec::Core::Example::ExecutionResult:0x00000002befd50>
block: #<Proc:0x00000002bf81a8@C:/rspec_tutorial/spec/metadata_spec.rb:7>
description_args: ["can access the metadata variable in the context block"]
description: can access the metadata variable in the context block
full_description: An Example Group with a metadata variable and a context 
   with another variable can access the metadata variable in the context block
described_class:
file_path: ./metadata_spec.rb
line_number: 7
location: ./metadata_spec.rb:7
absolute_file_path: C:/rspec_tutorial/spec/metadata_spec.rb
rerun_file_path: ./metadata_spec.rb
scoped_id: 1:1:2
foo: 17
bar: 12
example_group:
{:execution_result=>#<RSpec::Core::Example::ExecutionResult:
   0x00000002bfa0e8>, :block=>#<
   Proc:0x00000002bfac00@C:/rspec_tutorial/spec/metadata_spec.rb:2>, 
   :description_args=>["and a context with another variable"], 
	
   :description=>"and a context with another variable", 
   :full_description=>"An Example Group with a metadata variable
   and a context with another variable", :described_class=>nil, 
      :file_path=>"./metadata_spec.rb", 
		
   :line_number=>2, :location=>"./metadata_spec.rb:2", 
      :absolute_file_path=>"C:/rspec_tutorial/spec/metadata_spec.rb",
      :rerun_file_path=>"./metadata_spec.rb", 
		
   :scoped_id=>"1:1", :foo=>17, :parent_example_group=>
      {:execution_result=>#<
      RSpec::Core::Example::ExecutionResult:0x00000002c1f690>, 
      :block=>#<Proc:0x00000002baff70@C:/rspec_tutorial/spec/metadata_spec.rb:1>
      , :description_args=>["An Example Group with a metadata variable"], 
		
   :description=>"An Example Group with a metadata variable", 
   :full_description=>"An Example Group with a metadata variable", 
	:described_class=>nil, :file_path=>"./metadata_spec.rb", 
   :line_number=>1, :location=>"./metadata_spec.rb:1",
   :absolute_file_path=>
	
   "C:/rspec_tutorial/spec/metadata_spec.rb", 
   :rerun_file_path=>"./metadata_spec.rb", 
   :scoped_id=>"1", :foo=>17}, 
   :bar=>12}shared_group_inclusion_backtrace: [] 
	
last_run_status: unknown .
.
Finished in 0.004 seconds (files took 0.11101 seconds to load) 
2 examples, 0 failures

最有可能的是，您不需要使用所有这些元数据，而是查看完整的描述值

参考链接

https://www.learnfk.com/rspec/rspec-metadata.html