openapi-processor/openapi-processor-spring#126, avoid duplicates

(cherry picked from commit 7874d6b)

Author: hauner

src/main/kotlin/io/openapiprocessor/core/model/EndpointResponse.kt

@@ -1,17 +1,6 @@
 /*
- * Copyright 2019-2020 the original authors
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
+ * Copyright 2019 https://github.com/openapi-processor/openapi-processor-core
+ * PDX-License-Identifier: Apache-2.0
  */
 
 package io.openapiprocessor.core.model
@@ -21,8 +10,6 @@ import io.openapiprocessor.core.model.datatypes.ResultDataType
 
 /**
  * The responses that can be returned by an endpoint method for one (successful) response.
- *
- * @author Martin Hauner
  */
 class EndpointResponse(
 
@@ -76,9 +63,9 @@ class EndpointResponse(
     /**
      * returns a list with all content types.
      */
-    val contentTypes: List<String>
+    val contentTypes: Set<String>
         get() {
-            val result = mutableListOf<String>()
+            val result = mutableSetOf<String>()
             if (!main.empty) {
                 result.add(main.contentType)
             }

src/test/groovy/com/github/hauner/openapi/core/model/EndpointMethodResponseSpec.groovy

@@ -65,4 +65,34 @@ class EndpointMethodResponseSpec extends Specification {
         result[1].errors.collect {it.contentType} == ['text/plain']
     }
 
+    void "provides distinct response content type groups" () {
+        def endpoint = endpoint('/foo', HttpMethod.GET) { eb ->
+            eb.responses { rs ->
+                rs.status ('200') {r ->
+                    r.response ('application/json',
+                        new CollectionDataType (new StringDataType ())) {
+                    }
+                }
+                rs.status ('400') {r ->
+                    r.response ('application/json',
+                        new CollectionDataType (new StringDataType ())) {
+                    }
+                }
+                rs.status ('401') {r ->
+                    r.response ('application/json',
+                        new CollectionDataType (new StringDataType ())) {
+                    }
+                }
+            }
+        }
+
+        when:
+        def result = endpoint.endpointResponses
+
+        then:
+        result.size () == 1
+        result[0].contentTypes == ['application/json'] as Set
+
+    }
+
 }