feat: support MessagePact with a string as a content #1619

consumer/junit/src/test/groovy/au/com/dius/pact/consumer/junit/MessagePactBuilderSpec.groovy

@@ -205,4 +205,19 @@ class MessagePactBuilderSpec extends Specification {
     then:
     generators.categories[category] == ['$.DT': new DateTimeGenerator("yyyy-MM-dd'T'HH:mm:ss")]
   }
+
+  @Issue('#1619')
+  def 'support non-json text formats'() {
+    when:
+    def pact = new MessagePactBuilder()
+      .consumer('MessagePactBuilderSpec')
+      .expectsToReceive('a message with text contents')
+      .withContent('a=b&c=d', 'application/x-www-form-urlencoded')
+      .toPact()
+    Message message = pact.interactions.first()
+
+    then:
+    message.contents.valueAsString() == 'a=b&c=d'
+    message.contents.contentType.toString() == 'application/x-www-form-urlencoded'
+  }
 }

consumer/src/main/kotlin/au/com/dius/pact/consumer/MessagePactBuilder.kt

@@ -17,11 +17,11 @@ import au.com.dius.pact.core.model.messaging.MessagePact
 /**
  * PACT DSL builder for v3 specification
  */
-class MessagePactBuilder(
+class MessagePactBuilder @JvmOverloads constructor(
   /**
    * The consumer for the pact.
    */
-  private var consumer: Consumer,
+  private var consumer: Consumer = Consumer(),
 
   /**
    * The provider for the pact.
@@ -38,7 +38,6 @@ class MessagePactBuilder(
    */
   private var messages: MutableList<Message> = mutableListOf()
 ) {
-
   /**
    * Name the provider that the consumer has a pact with.
    *
@@ -198,6 +197,24 @@ class MessagePactBuilder(
     return this
   }
 
+  /**
+   * Adds the text as the message contents
+   */
+  @JvmOverloads
+  fun withContent(contents: String, contentType: String = "text/plain"): MessagePactBuilder {
+    if (messages.isEmpty()) {
+      throw InvalidPactException("expectsToReceive is required before withMetaData")
+    }
+
+    val message = messages.last()
+    message.metaData["contentType"] = contentType
+
+    val ct = ContentType(contentType)
+    message.contents = OptionalBody.body(contents.toByteArray(ct.asCharset()), ct)
+
+    return this
+  }
+
   /**
    * Convert this builder into a Pact
    */