feat: Update Groovy message builder to be able to create a message wi…

…th a NULL body #1637

consumer/groovy/src/main/groovy/au/com/dius/pact/consumer/groovy/messaging/PactMessageBuilder.groovy

@@ -66,6 +66,14 @@ class PactMessageBuilder extends GroovyBuilder {
    * @param metaData
    */
   PactMessageBuilder withMetaData(Map metadata) {
+    this.withMetadata(metadata)
+  }
+
+  /**
+   * Metadata attached to the message
+   * @param metaData
+   */
+  PactMessageBuilder withMetadata(Map metadata) {
     if (messages.empty) {
       throw new InvalidPactException('expectsToReceive is required before withMetaData')
     }
@@ -90,7 +98,7 @@ class PactMessageBuilder extends GroovyBuilder {
    *  - contentType: optional content type of the message
    *  - prettyPrint: if the message content should be pretty printed
    */
-  PactMessageBuilder withContent(Map options = [:], Closure closure) {
+  PactMessageBuilder withContent(Map options = [:], def value) {
     if (messages.empty) {
       throw new InvalidPactException('expectsToReceive is required before withContent')
     }
@@ -103,11 +111,16 @@ class PactMessageBuilder extends GroovyBuilder {
       contentType = messages.last().metadata.contentType
     }
 
-    def body = new PactBodyBuilder(mimetype: contentType, prettyPrintBody: options.prettyPrint)
-    closure.delegate = body
-    closure.call()
-    messages.last().contents = OptionalBody.body(body.body.bytes, new ContentType(contentType))
-    messages.last().matchingRules.addCategory(body.matchers)
+    if (value instanceof Closure) {
+      Closure closure = value as Closure
+      def body = new PactBodyBuilder(mimetype: contentType, prettyPrintBody: options.prettyPrint)
+      closure.delegate = body
+      closure.call()
+      messages.last().contents = OptionalBody.body(body.body.bytes, new ContentType(contentType))
+      messages.last().matchingRules.addCategory(body.matchers)
+    } else {
+      messages.last().contents = OptionalBody.body(value.toString().bytes, new ContentType(contentType))
+    }
 
     this
   }

consumer/groovy/src/test/groovy/au/com/dius/pact/consumer/groovy/messaging/PactMessageBuilderSpec.groovy

@@ -149,4 +149,57 @@ class PactMessageBuilderSpec extends Specification {
       assert message.jsonContents
     }
   }
+
+  def 'receiving a message with a NULL body'() {
+    given:
+    builder {
+      expectsToReceive 'a confirmation delete message'
+      withMetadata(contentType: 'application/json', messageId: '12345678')
+      withContent(null)
+    }
+
+    when:
+    builder.run { Message message ->
+      def content = new JsonSlurper().parse(message.contentsAsBytes())
+      assert content == null
+    }
+
+    then:
+    true
+  }
+
+  def 'receiving a message with an empty body'() {
+    given:
+    builder {
+      expectsToReceive 'a confirmation delete message'
+      withMetadata(contentType: 'application/json', messageId: '12345678')
+      withContent { }
+    }
+
+    when:
+    builder.run { Message message ->
+      def content = new JsonSlurper().parse(message.contentsAsBytes())
+      assert content.size() == 0
+    }
+
+    then:
+    true
+  }
+
+  def 'receiving a message with a missing body'() {
+    given:
+    builder {
+      expectsToReceive 'a confirmation delete message'
+      withMetadata(messageId: '12345678')
+    }
+
+    when:
+    builder.run { Message message ->
+      assert message.contentsAsBytes().size() == 0
+      assert message.metadata.messageId == '12345678'
+    }
+
+    then:
+    true
+  }
 }