Failing tests for union merges when queried with inline fragments

packages/stitch/tests/typeMergingWithUnionsAndInlineFragments.test.ts

@@ -0,0 +1,191 @@
+import { stitchingDirectives } from '@graphql-tools/stitching-directives';
+import { makeExecutableSchema } from '@graphql-tools/schema';
+import { addMocksToSchema } from '@graphql-tools/mock';
+import { GraphQLSchema } from 'graphql/type/schema';
+import { stitchSchemas } from '@graphql-tools/stitch';
+import { graphql } from 'graphql/index';
+
+describe('Unions and Inline Fragments', () => {
+  const { allStitchingDirectivesTypeDefs, stitchingDirectivesTransformer } = stitchingDirectives();
+
+  let studentSchema = makeExecutableSchema({
+    typeDefs: /* GraphQL */ `
+      ${allStitchingDirectivesTypeDefs}
+      type Query {
+        student(id: String!): Student
+      }
+
+      type Student {
+        id: String!
+        name: String!
+        major: Major!
+      }
+
+      union Major = StubMajor
+
+      type StubMajor {
+        id: String!
+      }
+    `,
+  });
+
+  let majorsSchema = makeExecutableSchema({
+    typeDefs: /* GraphQL */ `
+      ${allStitchingDirectivesTypeDefs}
+      type Query {
+        major(id: String!): Major @merge(keyField: "id")
+      }
+
+      union Major = MajorError | MajorSuccess # Allow for different return values
+      type MajorError {
+        id: String!
+        code: String!
+      }
+
+      type MajorSuccess {
+        id: String!
+        name: String!
+      }
+    `,
+  });
+
+  let stitchedSchema: GraphQLSchema;
+
+  let studentResolvers;
+
+  let majorResolvers: any;
+
+  afterEach(() => {
+    jest.resetAllMocks();
+  });
+
+  beforeEach(() => {
+    studentResolvers = {
+      Major: {
+        __resolveType: (_obj: any) => {
+          return 'StubMajor';
+        },
+      },
+      Query: {
+        student: async (_source: any, args: { id: string }) => {
+          return {
+            id: args.id,
+            name: 'Bob',
+            major: {
+              id: 'COMM.1231',
+            },
+          };
+        },
+      },
+    };
+
+    majorResolvers = {
+      Major: {
+        __resolveType: (obj: any) => {
+          if (obj.name) return 'MajorSuccess';
+          if (obj.code) return 'MajorError';
+          return null;
+        },
+      },
+      Query: {
+        major: async (
+          _source: any,
+          args: { id: string }
+        ): Promise<{ id: string; name: string } | { id: string; code: string }> => {
+          return {
+            id: args.id,
+            name: 'Communications',
+          };
+        },
+      },
+    };
+
+    studentSchema = addMocksToSchema({
+      schema: studentSchema,
+      resolvers: studentResolvers,
+    });
+    majorsSchema = addMocksToSchema({
+      schema: majorsSchema,
+      resolvers: majorResolvers,
+    });
+
+    stitchedSchema = stitchSchemas({
+      subschemas: [{ schema: studentSchema }, { schema: majorsSchema }],
+      subschemaConfigTransforms: [stitchingDirectivesTransformer],
+      resolverValidationOptions: { requireResolversForResolveType: 'ignore' },
+    });
+  });
+  it('handles success', async () => {
+    const query = /* GraphQL */ `
+      query {
+        student(id: "12314241") {
+          id
+          name
+          major {
+            ... on MajorSuccess {
+              id
+              name
+            }
+            ... on MajorError {
+              id
+              code
+            }
+          }
+        }
+      }
+    `;
+
+    const result = await graphql({
+      schema: stitchedSchema,
+      source: query,
+    });
+    expect(result.errors).toBe(undefined);
+    expect(result.data).toEqual({
+      student: {
+        id: '12314241',
+        name: 'Bob',
+        major: {
+          id: 'COMM.1231',
+          name: 'Communications',
+        },
+      },
+    });
+  });
+  it('error', async () => {
+    const query = /* GraphQL */ `
+      query {
+        student(id: "12314241") {
+          id
+          name
+          major {
+            ... on MajorSuccess {
+              id
+              name
+            }
+            ... on MajorError {
+              id
+              code
+            }
+          }
+        }
+      }
+    `;
+    const majorsSpy = jest.spyOn(majorResolvers.Query, 'major');
+    majorsSpy.mockResolvedValue({ id: 'COMM.1231', code: 'NOT_FOUND' });
+    const result = await graphql({
+      schema: stitchedSchema,
+      source: query,
+    });
+    expect(result.errors).toBe(undefined);
+    expect(result.data).toEqual({
+      student: {
+        id: '12314241',
+        name: 'Bob',
+        major: {
+          id: 'COMM.1231',
+          code: 'NOT_FOUND',
+        },
+      },
+    });
+  });
+});