Add JUnitTests covering the Polymorphic support

samples/junit-tests/src/test/java/com/yelp/codegen/generatecodesamples/PolymorphismEndpointTest.kt

@@ -0,0 +1,167 @@
+package com.yelp.codegen.generatecodesamples
+
+import com.squareup.moshi.JsonDataException
+import com.yelp.codegen.generatecodesamples.apis.PolymorphismApi
+import com.yelp.codegen.generatecodesamples.models.Animal
+import com.yelp.codegen.generatecodesamples.models.Cat
+import com.yelp.codegen.generatecodesamples.models.Dog
+import com.yelp.codegen.generatecodesamples.tools.MockServerApiRule
+import okhttp3.mockwebserver.MockResponse
+import org.junit.Assert.assertEquals
+import org.junit.Assert.assertTrue
+import org.junit.Rule
+import org.junit.Test
+
+class PolymorphismEndpointTest {
+
+    @get:Rule
+    val rule = MockServerApiRule()
+
+    @Test
+    fun checkPolymorphicReturnsBaseModel() {
+        rule.server.enqueue(
+            MockResponse().setBody(
+                """
+            {
+                "name": "a name",
+                "type": "animal"
+            }
+                """.trimIndent()
+            )
+        )
+
+        val returned = rule.getApi<PolymorphismApi>().getCheckPolymorphism().blockingGet()
+        assertEquals(
+            Animal(
+                name = "a name",
+                type = "animal",
+                classification = null
+            ),
+            returned
+        )
+        assertTrue(returned is Animal)
+        assertTrue(returned !is Cat)
+        assertTrue(returned !is Dog)
+    }
+
+    @Test
+    fun checkPolymorphicReturnsBaseModelWhenUnknownDiscriminator() {
+        rule.server.enqueue(
+            MockResponse().setBody(
+                """
+            {
+                "name": "a name",
+                "type": "snake",
+                "classification": "reptile"
+            }
+                """.trimIndent()
+            )
+        )
+
+        val returned = rule.getApi<PolymorphismApi>().getCheckPolymorphism().blockingGet()
+        assertEquals(
+            Animal(
+                name = "a name",
+                type = "snake",
+                classification = Animal.ClassificationEnum.REPTILE
+            ),
+            returned
+        )
+        assertTrue(returned is Animal)
+        assertTrue(returned !is Cat)
+        assertTrue(returned !is Dog)
+    }
+
+    @Test
+    fun checkPolymorphicReturnsDiscriminatedModelWhenRecognized() {
+        rule.server.enqueue(
+            MockResponse().setBody(
+                """
+            {
+                "name": "a name",
+                "type": "Cat",
+                "classification": "mammal",
+                "age": 42
+            }
+                """.trimIndent()
+            )
+        )
+
+        val returned = rule.getApi<PolymorphismApi>().getCheckPolymorphism().blockingGet()
+        assertEquals(
+            Animal(
+                name = "a name",
+                type = "Cat",
+                classification = Animal.ClassificationEnum.MAMMAL
+            ),
+            returned
+        )
+        assertEquals(
+            Cat(
+                name = "a name",
+                type = "Cat",
+                classification = Animal.ClassificationEnum.MAMMAL,
+                age = 42.toBigDecimal()
+            ),
+            returned
+        )
+        assertTrue(returned is Animal)
+        assertTrue(returned is Cat)
+        assertTrue(returned !is Dog)
+    }
+
+    @Test
+    fun checkPolymorphicReturnsDiscriminatedModelWhenRecognizedAndInnerModelHasEnum() {
+        rule.server.enqueue(
+            MockResponse().setBody(
+                """
+            {
+                "name": "a name",
+                "type": "dog",
+                "classification": "mammal",
+                "size": "small"
+            }
+                """.trimIndent()
+            )
+        )
+
+        val returned = rule.getApi<PolymorphismApi>().getCheckPolymorphism().blockingGet()
+        assertEquals(
+            Animal(
+                name = "a name",
+                type = "dog",
+                classification = Animal.ClassificationEnum.MAMMAL
+            ),
+            returned
+        )
+        assertEquals(
+            Dog(
+                name = "a name",
+                type = "dog",
+                classification = Animal.ClassificationEnum.MAMMAL,
+                size = Dog.SizeEnum.SMALL
+            ),
+            returned
+        )
+        assertTrue(returned is Animal)
+        assertTrue(returned !is Cat)
+        assertTrue(returned is Dog)
+    }
+
+    @Test(expected = JsonDataException::class)
+    fun checkPolymorphicDoesNotReturnBaseModelIfDiscriminatedModelIsIdentifiedAnFailedToParse() {
+        rule.server.enqueue(
+            MockResponse().setBody(
+                """
+            {
+                "name": "a name",
+                "type": "dog",
+                "classification": "mammal"
+            }
+                """.trimIndent()
+            )
+        )
+
+        rule.getApi<PolymorphismApi>().getCheckPolymorphism().blockingGet()
+    }
+}