Add test to show how to generate nullable types instead of primitives #1023

Author: kobylynskyi

src/test/java/com/kobylynskyi/graphql/codegen/GraphQLCodegenOptionalTest.java

@@ -12,8 +12,10 @@
 import java.io.File;
 import java.io.IOException;
 import java.nio.file.Paths;
+import java.util.HashMap;
 import java.util.Objects;
 
+import static com.kobylynskyi.graphql.codegen.TestUtils.assertFileContainsElements;
 import static com.kobylynskyi.graphql.codegen.TestUtils.assertSameTrimmedContent;
 import static com.kobylynskyi.graphql.codegen.TestUtils.getFileByName;
 
@@ -98,6 +100,26 @@ void generate_OptionalFieldInInterfaceAndMandatoryInType() throws Exception {
                 getFileByName(files, "TypeWithMandatoryField.java"));
     }
 
+    /**
+     * @see <a href="https://github.com/kobylynskyi/graphql-java-codegen/issues/1023">Related issue in GitHub</a>
+     */
+    @Test
+    void generate_ObjectsInsteadOfPrimitives() throws Exception {
+        mappingConfig.setCustomTypesMapping(new HashMap<String, String>() {{
+            put("Int!", "Integer");
+        }});
+        schemaFinder.setIncludePattern("optional-vs-mandatory-types.graphqls");
+
+        generate();
+
+        File[] files = Objects.requireNonNull(outputJavaClassesDir.listFiles());
+
+        // Integer is generated instead of int
+        assertFileContainsElements(files, "TypeWithMandatoryField.java",
+                "    @javax.validation.constraints.NotNull",
+                "    private Integer test;");
+    }
+
     private void generate() throws IOException {
         new JavaGraphQLCodegen(schemaFinder.findSchemas(), outputBuildDir, mappingConfig,
                 TestUtils.getStaticGeneratedInfo(mappingConfig)).generate();