chore: add Kotlin Junit5 message test

consumer/junit5/src/test/kotlin/au/com/dius/pact/consumer/junit5/KotlinV4MessageTest.kt

@@ -0,0 +1,49 @@
+package au.com.dius.pact.consumer.junit5
+
+import au.com.dius.pact.consumer.dsl.LambdaDsl.newJsonBody
+import au.com.dius.pact.consumer.dsl.PactBuilder
+import au.com.dius.pact.core.model.PactSpecVersion
+import au.com.dius.pact.core.model.V4Pact
+import au.com.dius.pact.core.model.annotations.Pact
+import org.hamcrest.MatcherAssert.assertThat
+import org.hamcrest.Matchers.equalTo
+import org.hamcrest.Matchers.`is`
+import org.hamcrest.Matchers.notNullValue
+import org.junit.jupiter.api.Test
+import org.junit.jupiter.api.extension.ExtendWith
+
+@ExtendWith(value = [PactConsumerTestExt::class])
+@PactTestFor(providerName = "checkout-service", providerType = ProviderType.ASYNCH, pactVersion = PactSpecVersion.V4)
+class KotlinV4MessageTest {
+
+  private val jsonBody = newJsonBody { o ->
+    o.stringType("purchaseId", "111")
+    o.stringType("name", "PURCHASE_STARTED")
+    o.eachLike("products", 1) { items ->
+      items.stringType("productID", "1")
+      items.stringType("productType", "FLIGHT")
+      items.stringType("availabilityId", "28e80c5987c6a242516ccdc004235b5e")
+    }
+  }.build()
+
+  @Pact(consumer = "reservation-service", provider = "checkout-service")
+  fun pactForReservationBooking(builder: PactBuilder): V4Pact {
+    return builder
+      .usingLegacyMessageDsl()
+      .hasPactWith("checkout-service")
+      .expectsToReceive("a purchase started message to book a reservation")
+      .withContent(jsonBody)
+      .toPact()
+  }
+
+  @Test
+  @PactTestFor(pactMethod = "pactForReservationBooking")
+  fun testPactForReservationBooking(pact: V4Pact) {
+    val message = pact.interactions.firstOrNull()
+    assertThat(message, `is`(notNullValue()))
+    assertThat(message!!.asAsynchronousMessage()!!.contents.contents.valueAsString(),
+      `is`(equalTo("{\"name\":\"PURCHASE_STARTED\",\"products\":[{\"availabilityId\":" +
+        "\"28e80c5987c6a242516ccdc004235b5e\",\"productID\":\"1\",\"productType\":\"FLIGHT\"}]," +
+        "\"purchaseId\":\"111\"}")))
+  }
+}