Add compilation tests for reqiured and optional fields

Author: jasgin

codegen-server/src/test/kotlin/software/amazon/smithy/rust/codegen/server/smithy/customizations/CustomValidationExceptionDecoratorTest.kt

@@ -11,7 +11,9 @@ import org.junit.jupiter.api.Test
 import software.amazon.smithy.model.Model
 import software.amazon.smithy.model.shapes.ShapeId
 import software.amazon.smithy.model.shapes.StructureShape
+import software.amazon.smithy.rust.codegen.core.rustlang.rust
 import software.amazon.smithy.rust.codegen.core.testutil.asSmithyModel
+import software.amazon.smithy.rust.codegen.server.smithy.testutil.serverIntegrationTest
 import software.amazon.smithy.rust.codegen.server.smithy.testutil.serverTestCodegenContext
 import software.amazon.smithy.rust.codegen.traits.ValidationExceptionTrait
 import software.amazon.smithy.rust.codegen.traits.ValidationFieldListTrait
@@ -204,4 +206,154 @@ internal class CustomValidationExceptionDecoratorTest {
 
         generator shouldBe null
     }
+
+    private val completeTestModel =
+        """
+        namespace com.aws.example
+
+        use aws.protocols#restJson1
+        use smithy.rust.codegen.traits#validationException
+        use smithy.rust.codegen.traits#validationFieldList
+        use smithy.rust.codegen.traits#validationFieldMessage
+        use smithy.rust.codegen.traits#validationFieldName
+        use smithy.rust.codegen.traits#validationMessage
+
+        @restJson1
+        service CustomValidationExample {
+            version: "1.0.0"
+            operations: [
+                TestOperation
+            ]
+            errors: [
+                MyCustomValidationException
+            ]
+        }
+
+        @http(method: "POST", uri: "/test")
+        operation TestOperation {
+            input: TestInput
+        }
+
+        structure TestInput {
+            @required
+            @length(min: 1, max: 10)
+            name: String
+
+            @range(min: 1, max: 100)
+            age: Integer
+        }
+
+        @error("client")
+        @httpError(400)
+        @validationException
+        structure MyCustomValidationException {
+            @required
+            @validationMessage
+            customMessage: String
+
+            @required
+            @default("testReason1")
+            reason: ValidationExceptionReason
+
+            @validationFieldList
+            customFieldList: CustomValidationFieldList
+        }
+
+        enum ValidationExceptionReason {
+            TEST_REASON_0 = "testReason0"
+            TEST_REASON_1 = "testReason1"
+        }
+
+        structure CustomValidationField {
+            @required
+            @validationFieldName
+            customFieldName: String
+
+            @required
+            @validationFieldMessage
+            customFieldMessage: String
+        }
+
+        list CustomValidationFieldList {
+            member: CustomValidationField
+        }
+        """.asSmithyModel(smithyVersion = "2.0")
+
+    @Test
+    fun `code compiles with custom validation exception`() {
+        serverIntegrationTest(completeTestModel)
+    }
+
+    private val completeTestModelWithOptionals =
+        """
+        namespace com.aws.example
+
+        use aws.protocols#restJson1
+        use smithy.rust.codegen.traits#validationException
+        use smithy.rust.codegen.traits#validationFieldList
+        use smithy.rust.codegen.traits#validationFieldMessage
+        use smithy.rust.codegen.traits#validationFieldName
+        use smithy.rust.codegen.traits#validationMessage
+
+        @restJson1
+        service CustomValidationExample {
+            version: "1.0.0"
+            operations: [
+                TestOperation
+            ]
+            errors: [
+                MyCustomValidationException
+            ]
+        }
+
+        @http(method: "POST", uri: "/test")
+        operation TestOperation {
+            input: TestInput
+        }
+
+        structure TestInput {
+            @required
+            @length(min: 1, max: 10)
+            name: String
+
+            @range(min: 1, max: 100)
+            age: Integer
+        }
+
+        @error("client")
+        @httpError(400)
+        @validationException
+        structure MyCustomValidationException {
+            @validationMessage
+            customMessage: String
+
+            @default("testReason1")
+            reason: ValidationExceptionReason
+
+            @validationFieldList
+            customFieldList: CustomValidationFieldList
+        }
+
+        enum ValidationExceptionReason {
+            TEST_REASON_0 = "testReason0"
+            TEST_REASON_1 = "testReason1"
+        }
+
+        structure CustomValidationField {
+            @validationFieldName
+            customFieldName: String
+
+            @validationFieldMessage
+            customFieldMessage: String
+        }
+
+        list CustomValidationFieldList {
+            member: CustomValidationField
+        }
+        """.asSmithyModel(smithyVersion = "2.0")
+
+    @Test
+    fun `code compiles with custom validation exception using optionals`() {
+        serverIntegrationTest(completeTestModelWithOptionals)
+    }
 }