如何在 Rspec-Rails 中引发运行时错误

Question

I have to test a code where I am raising some errors, I tried several techniques but it failed. The structure of the class is defined below:

SchemaController:

class SchemasController < ApplicationController
  def index
    @get_schema = Api::AnalyticsQueryBuilderMetadataService::Schema.show
  end
end

Show method under Api -> AnalyticsQueryBuilderMetadataService -> Schema.rb file:

def self.show
        params = { 'limit' => 40 }
        response = Api::Connection.initiate_request('entities', params)
        if response.nil?
           Rails.logger.error 'Data not found for ClientId '
           raise 'Data not found'
        else
           get_schema(response)
        end
end

Rspec test I wrote for schema_spec.rb:

require 'rails_helper'
require 'spec_helper'

RSpec.describe Api::AnalyticsQueryBuilderMetadataService::Schema do
  describe 'GET all schema' do
    before do
      # allow_any_instance_of(SchemasController).to receive(:connection).and_return({})
      #binding.pry
      allow(Api::Connection).to receive(:initiate_request).and_return(nil)
    end

    context 'When no json body is passed' do
      it 'Raises NoMethodError' do
        # obj = SchemasController.new
        result = Api::AnalyticsQueryBuilderMetadataService::Schema.show()
        # expect {result}.to raise_error(RuntimeError)
        expect{result}.to raise_error
      end

      
    end
  end
end

But It is giving error as:

Failures:

  1) Api::AnalyticsQueryBuilderMetadataService::Schema GET all schema When no json body is passed Raises NoMethodError
     Failure/Error: raise 'Data not found'
     
     RuntimeError:
       Data not found
     # ./app/lib/api/analytics_query_builder_metadata_service/schema.rb:22:in `show'
     # ./spec/lib/api/analytics_query_builder_metadata_service/schema_spec.rb:17:in `block (4 levels) in <top (required)>'

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44 examples, 1 failure

Failed examples:

rspec ./spec/lib/api/analytics_query_builder_metadata_service/schema_spec.rb:15 # Api::AnalyticsQueryBuilderMetadataService::Schema GET all schema When no json body is passed Raises NoMethodError

Help me to solve this.

Answer 1

From the docs;

Use the raise_error matcher to specify that a block of code raises an error.

It means that the code in the block should be the one raising the error, but in your case the error is being raised when you declare the result variable.

To make it work you can skip the variable declaration and pass the variable value as the expect block;

expect { Api::AnalyticsQueryBuilderMetadataService::Schema.show }
  .to raise_error(StandardError, 'Data not found')