refactor: simplify Fn::Sub when only pseudo params

Author: theburningmonk

lib/deploy/stepFunctions/compileStateMachines.js

@@ -122,9 +122,14 @@ module.exports = {
 
             if (!replaced && _.isEmpty(functionMappings)) {
               DefinitionString = definitionString;
+            } else if (_.isEmpty(functionMappings)) {
+              DefinitionString = {
+                'Fn::Sub': definitionString,
+              };
             } else {
               const f = translateLocalFunctionNames.bind(this);
               const params = _.fromPairs(functionMappings.map(([k, v]) => [k, f(v)]));
+
               DefinitionString = {
                 'Fn::Sub': [
                   definitionString,

lib/deploy/stepFunctions/compileStateMachines.test.js

@@ -1142,11 +1142,10 @@ describe('#compileStateMachines', () => {
       .DefinitionString;
 
     expect(actual).to.haveOwnProperty('Fn::Sub');
-    const [definitionString, params] = actual['Fn::Sub'];
+    const definitionString = actual['Fn::Sub'];
     expect(definitionString).to.contain('${AWS::Region}');
     expect(definitionString).to.not.contain('#{AWS::Region}');
     expect(definitionString).to.contain('${AWS::AccountId}');
     expect(definitionString).to.not.contain('#{AWS::AccountId}');
-    expect(params).to.deep.equal({});
   });
 });