Add test for stable directive definition

Author: gnawf

lib/src/test/kotlin/graphql/nadel/definition/stubbed/NadelStubbedDefinitionTest.kt

@@ -0,0 +1,35 @@
+package graphql.nadel.definition.stubbed
+
+import graphql.introspection.Introspection.DirectiveLocation
+import graphql.introspection.Introspection.DirectiveLocation.ENUM
+import graphql.introspection.Introspection.DirectiveLocation.FIELD_DEFINITION
+import graphql.introspection.Introspection.DirectiveLocation.INPUT_OBJECT
+import graphql.introspection.Introspection.DirectiveLocation.OBJECT
+import graphql.introspection.Introspection.DirectiveLocation.UNION
+import kotlin.test.Test
+import kotlin.test.assertTrue
+
+class NadelStubbedDefinitionTest {
+    @Test
+    fun `directive name are stable`() {
+        assertTrue(NadelStubbedDefinition.directiveDefinition.name == "stubbed")
+    }
+
+    @Test
+    fun `directive locations are stable`() {
+        // Given
+        val expectedLocations = setOf(
+            FIELD_DEFINITION,
+            OBJECT,
+            INPUT_OBJECT,
+            UNION,
+            ENUM,
+        )
+        val actualLocations = NadelStubbedDefinition.directiveDefinition.directiveLocations.mapTo(mutableSetOf()) {
+            DirectiveLocation.valueOf(it.name)
+        }
+
+        // Then
+        assertTrue(actualLocations == expectedLocations)
+    }
+}