Add a test to check customTypeMapping is working from a service block (apollographql#1991)

Author: martinbonnin

apollo-gradle-plugin/src/test/kotlin/com/apollographql/apollo/gradle/test/ConfigurationTests.kt

@@ -28,6 +28,24 @@ class ConfigurationTests {
     }
   }
 
+  @Test
+  fun `customTypeMapping can be applied from a service block`() {
+    withSimpleProject("""
+      apollo {
+        service("other") {
+          schemaPath = "com/example/schema.json"
+        }
+        service("api") {
+          customTypeMapping = ["DateTime": "java.util.Date"]
+          schemaPath = "com/example/schema.json"
+        }
+      }
+    """.trimIndent()) { dir ->
+      TestUtils.executeTask("generateApolloSources", dir)
+      TestUtils.assertFileContains(dir, "main/api/com/example/type/CustomType.java", "return Date.class;")
+    }
+  }
+
   @Test
   fun `nullableValueType is working`() {
     for (pair in listOf(