feat(1765): update tests, move unit test to proper file, improve removeEmptyInterfaces algo

Signed-off-by: Martin Jirku <martin@jirku.sk>

script/test/fixtures/compose-file-env-variable/output-k8s.yaml

@@ -2,7 +2,6 @@
 apiVersion: v1
 kind: Service
 metadata:
-  creationTimestamp: null
   labels:
     io.kompose.service: alpine
   name: alpine
@@ -18,7 +17,6 @@ spec:
 apiVersion: v1
 kind: Service
 metadata:
-  creationTimestamp: null
   labels:
     io.kompose.service: debian
   name: debian
@@ -34,7 +32,6 @@ spec:
 apiVersion: apps/v1
 kind: Deployment
 metadata:
-  creationTimestamp: null
   labels:
     io.kompose.service: alpine
   name: alpine
@@ -43,10 +40,8 @@ spec:
   selector:
     matchLabels:
       io.kompose.service: alpine
-  strategy: {}
   template:
     metadata:
-      creationTimestamp: null
       labels:
         io.kompose.network/compose-file-env-variable-default: "true"
         io.kompose.service: alpine
@@ -58,14 +53,12 @@ spec:
             - containerPort: 80
               hostPort: 80
               protocol: TCP
-          resources: {}
       restartPolicy: Always
 
 ---
 apiVersion: apps/v1
 kind: Deployment
 metadata:
-  creationTimestamp: null
   labels:
     io.kompose.service: debian
   name: debian
@@ -74,10 +67,8 @@ spec:
   selector:
     matchLabels:
       io.kompose.service: debian
-  strategy: {}
   template:
     metadata:
-      creationTimestamp: null
       labels:
         io.kompose.network/compose-file-env-variable-default: "true"
         io.kompose.service: debian
@@ -89,6 +80,5 @@ spec:
             - containerPort: 80
               hostPort: 80
               protocol: TCP
-          resources: {}
       restartPolicy: Always