Add test for multiple checks failing

Also sort the check keys to make sure they are in consistent order

lib/deployment/events/lambda_function_failed.rb

@@ -8,7 +8,7 @@ def initialize(event)
 
       def error
         if preflight_checks_failed?
-          "The following pre-flight checks have failed: #{preflight_checks_failed.join(',')}. "\
+          "The following pre-flight checks have failed: #{preflight_checks_failed.join(', ')}. "\
           'See https://www.notion.so/freeagent/Deployment-Playbooks-aa0f91db24954b328ebfc7d87963a185#3193a48ea76e46b29a38027150612b0d'
         else
           @error_message
@@ -22,7 +22,7 @@ def preflight_checks_failed?
       end
 
       def preflight_checks_failed
-        preflight_checks_output.select { |_k, v| v == 'FAILED' }.keys
+        preflight_checks_output.select { |_k, v| v == 'FAILED' }.keys.sort
       end
 
       def preflight_checks_output

spec/lambda_function_failed_spec.rb

@@ -5,7 +5,7 @@
 RSpec.describe Deployment::Events::LambdaFunctionFailed do
   subject(:deployment) { Deployment::Events::LambdaFunctionFailed.new(event) }
 
-  context 'forward deploy pre-flight check failed' do
+  context 'one pre flight check failed' do
     let(:event) do
       Aws::States::Types::HistoryEvent.new(
         type: 'LambdaFunctionFailed',
@@ -29,14 +29,14 @@
     end
   end
 
-  context 'some other pre-flight check failed' do
+  context 'multiple pre flight checks failed' do
     let(:event) do
       Aws::States::Types::HistoryEvent.new(
         type: 'LambdaFunctionFailed',
         lambda_function_failed_event_details: Aws::States::Types::LambdaFunctionFailedEventDetails.new(
           cause: '
             {
-              "errorMessage": "Pre flight checks failed:\n{\"Checks\"=>{:RequiredParameters=>\"FAILED\", :CommitCheck=>\"PASSED\", :ScheduleCheck=>\"PASSED\", :ForwardDeployCheck=>\"PASSED\"}, \"Status\"=>\"FAILED\"}",
+              "errorMessage": "Pre flight checks failed:\n{\"Checks\"=>{:RequiredParameters=>\"FAILED\", :CommitCheck=>\"FAILED\", :ScheduleCheck=>\"FAILED\", :ForwardDeployCheck=>\"PASSED\"}, \"Status\"=>\"FAILED\"}",
               "errorType": "Function<StandardError>",
               "stackTrace": [
                 "/var/task/pre_flight_checks.rb:145:in `handler"
@@ -48,7 +48,7 @@
 
     describe(:error) do
       it 'returns full preflight failure details' do
-        expect(deployment.error).to start_with('The following pre-flight checks have failed: RequiredParameters.')
+        expect(deployment.error).to start_with('The following pre-flight checks have failed: CommitCheck, RequiredParameters, ScheduleCheck.')
       end
     end
   end