add expectedFieldsStack and validate extra fields after traversal

Author: lopert

src/methods/validate-fixture-input.ts

@@ -13,6 +13,34 @@ import {
 } from "graphql";
 import { inlineNamedFragmentSpreads } from "../utils/inline-named-fragment-spreads.js";
 
+/**
+ * Checks fixture objects for fields that are not present in the GraphQL query.
+ *
+ * @param fixtureObjects - Array of fixture objects to validate
+ * @param expectedFields - Set of field names that are expected based on the query
+ * @returns Array of error messages for any extra fields found (empty if valid)
+ *
+ * @remarks
+ * Only validates object types - skips null values and arrays.
+ */
+function checkForExtraFields(
+  fixtureObjects: any[],
+  expectedFields: Set<string>
+): string[] {
+  const errors: string[] = [];
+  for (const fixtureObject of fixtureObjects) {
+    if (typeof fixtureObject === "object" && fixtureObject !== null && !Array.isArray(fixtureObject)) {
+      const fixtureFields = Object.keys(fixtureObject);
+      for (const fixtureField of fixtureFields) {
+        if (!expectedFields.has(fixtureField)) {
+          errors.push(`Extra field "${fixtureField}" found in fixture data not in query`);
+        }
+      }
+    }
+  }
+  return errors;
+}
+
 export interface ValidateFixtureInputResult {
   errors: string[];
 }
@@ -37,6 +65,7 @@ export function validateFixtureInput(
   const inlineFragmentSpreadsAst = inlineNamedFragmentSpreads(queryAST);
   const typeInfo = new TypeInfo(schema);
   const valueStack: any[][] = [[value]];
+  const expectedFieldsStack: Set<string>[] = [new Set()]; // Initial set tracks root level fields
   const errors: string[] = [];
   visit(
     inlineFragmentSpreadsAst,
@@ -48,6 +77,9 @@ export function validateFixtureInput(
 
           const responseKey = node.alias?.value || node.name.value;
 
+          // Track this field as expected in the parent's set
+          expectedFieldsStack[expectedFieldsStack.length - 1].add(responseKey);
+
           const fieldDefinition = typeInfo.getFieldDef();
           const fieldType = fieldDefinition?.type;
 
@@ -124,10 +156,21 @@ export function validateFixtureInput(
             }
           }
 
+          // If this field has nested selections, prepare to track expected child fields
+          if (node.selectionSet) {
+            expectedFieldsStack.push(new Set<string>());
+          }
+
           valueStack.push(nestedValues);
         },
-        leave() {
-          valueStack.pop();
+        leave(node) {
+          const nestedValues = valueStack.pop()!;
+
+          // If this field had nested selections, check for extra fields
+          if (node.selectionSet) {
+            const expectedFields = expectedFieldsStack.pop()!;
+            errors.push(...checkForExtraFields(nestedValues, expectedFields));
+          }
         },
       },
       SelectionSet: {
@@ -155,6 +198,11 @@ export function validateFixtureInput(
       },
     })
   );
+
+  // The query's root SelectionSet has no parent Field node, so there's no Field.leave event to check it.
+  // We manually perform the same check here that would happen in Field.leave for nested objects.
+  errors.push(...checkForExtraFields(valueStack[0], expectedFieldsStack[0]));
+
   return { errors };
 }
 

test/methods/validate-fixture-input.test.ts

@@ -74,16 +74,12 @@ describe("validateFixtureInput", () => {
           firstItems: [
             {
               id: "gid://test/Item/1",
-              count: 5,
-              details: {
-                name: "First Item"
-              }
+              count: 5
             }
           ],
           secondItems: [
             {
               id: "gid://test/Item/1",
-              count: 5,
               details: {
                 name: "First Item"
               }
@@ -729,7 +725,7 @@ describe("validateFixtureInput", () => {
     // in fixture data that aren't present in the query. Currently, it only validates
     // that all required fields from the query are present in the fixture, but doesn't
     // flag additional fields that shouldn't be there.
-    it.skip("detects extra fields not in query", () => {
+    it("detects extra fields not in query", () => {
       const queryAST = parse(`
         query Query {
           data {
@@ -938,5 +934,54 @@ describe("validateFixtureInput", () => {
       expect(result.errors).toHaveLength(1);
       expect(result.errors[0]).toBe('Cannot validate nonExistentField: missing type information');
     });
+
+    it("detects extra fields with multiple aliases for the same field", () => {
+      const queryAST = parse(`
+        query Query {
+          data {
+            firstItems: items {
+              id
+              count
+            }
+            secondItems: items {
+              id
+              details {
+                name
+              }
+            }
+          }
+        }
+      `);
+
+      const fixtureInput = {
+        data: {
+          firstItems: [
+            {
+              id: "gid://test/Item/1",
+              count: 5,
+              details: {
+                name: "First Item"
+              }
+            }
+          ],
+          secondItems: [
+            {
+              id: "gid://test/Item/1",
+              count: 5,
+              details: {
+                name: "First Item"
+              }
+            }
+          ]
+        }
+      };
+
+      const result = validateFixtureInput(queryAST, schema, fixtureInput);
+
+      // Each alias is validated independently, so extra fields in each should be detected
+      expect(result.errors).toHaveLength(2);
+      expect(result.errors[0]).toBe('Extra field "details" found in fixture data not in query');
+      expect(result.errors[1]).toBe('Extra field "count" found in fixture data not in query');
+    });
   });
 });

test/methods/validate-test-assets.test.ts

@@ -140,10 +140,11 @@ describe('validateTestAssets', () => {
 
       expect(result.inputQuery.errors).toHaveLength(0);
 
-      // Input fixture should be invalid due to missing fields
-      expect(result.inputFixture.errors.length).toBe(2);
+      // Input fixture should be invalid due to missing fields and extra field
+      expect(result.inputFixture.errors.length).toBe(3);
       expect(result.inputFixture.errors[0]).toBe('Missing expected fixture data for details');
-      expect(result.inputFixture.errors[1]).toBe('Missing expected fixture data for metadata');
+      expect(result.inputFixture.errors[1]).toBe('Extra field "invalidField" found in fixture data not in query');
+      expect(result.inputFixture.errors[2]).toBe('Missing expected fixture data for metadata');
 
       expect(result.outputFixture.errors).toHaveLength(0);
     });