fix(common): adding feature flag for default serviceaccount name (#360)

charts/library/common-test/tests/serviceAccount/serviceaccount_test.yaml

@@ -27,6 +27,41 @@ tests:
         isKind:
           of: ServiceAccount
 
+  - it: controller uses named ServiceAccount by default
+    set:
+      serviceAccount:
+        create: false
+        name: &ServiceAccountName test
+
+    asserts:
+      - hasDocuments:
+          count: 1
+      - documentIndex: &DeploymentDocument 0
+        isKind:
+          of: Deployment
+      - documentIndex: *DeploymentDocument
+        equal:
+          path: spec.template.spec.serviceAccountName
+          value: *ServiceAccountName
+
+  - it: controller uses `default` ServiceAccount if flag is enabled
+    set:
+      enforceServiceAccountCreation: true
+      serviceAccount:
+        create: false
+        name: test
+
+    asserts:
+      - hasDocuments:
+          count: 1
+      - documentIndex: &DeploymentDocument 0
+        isKind:
+          of: Deployment
+      - documentIndex: *DeploymentDocument
+        equal:
+          path: spec.template.spec.serviceAccountName
+          value: default
+
   - it: a serviceAccount and Secret are created when enabled
     set:
       serviceAccount: