Add tests

packages/graphql-codegen-cli/tests/config.spec.ts

@@ -0,0 +1,89 @@
+import { createContext, ensureContext } from '../src/index.js';
+
+describe('Codegen config - Context', () => {
+  it('loads and merge multiple schemas when using GraphQL config', async () => {
+    const context = await createContext({
+      config: './packages/graphql-codegen-cli/tests/test-files/graphql.config.js',
+      project: 'prj1',
+      errorsOnly: true,
+      overwrite: true,
+      profile: true,
+      require: [],
+      silent: false,
+      watch: false,
+    });
+
+    const schema1 = /* GraphQL */ `
+      type Query
+      scalar Date
+    `;
+
+    const schema2 = /* GraphQL */ `
+      extend type Query {
+        me: User
+      }
+      type User {
+        id: ID!
+        name: String!
+        createdAt: Date!
+      }
+    `;
+
+    const schema3 = /* GraphQL */ `
+      extend type Query {
+        media: Media
+      }
+      interface Media {
+        id: ID!
+      }
+      type Image implements Media {
+        id: ID!
+        url: String!
+      }
+      type Book implements Media {
+        id: ID!
+        title: String!
+      }
+    `;
+
+    const mergedSchema = await context.loadSchema([schema1, schema2, schema3]);
+
+    const typeMap = mergedSchema.getTypeMap();
+
+    expect(typeMap['Query']).toBeDefined();
+    expect(typeMap['Date']).toBeDefined();
+    expect(typeMap['User']).toBeDefined();
+    expect(typeMap['Media']).toBeDefined();
+    expect(typeMap['Image']).toBeDefined();
+    expect(typeMap['Book']).toBeDefined();
+  });
+
+  it('loads and merge multiple schemas when using input config', async () => {
+    const context = ensureContext({
+      generates: {},
+    });
+
+    const schema1 = /* GraphQL */ `
+      type Mutation
+      scalar DateTime
+    `;
+
+    const schema2 = /* GraphQL */ `
+      extend type Mutation {
+        createUser: User
+      }
+      type User {
+        id: ID!
+        createdAt: DateTime!
+      }
+    `;
+
+    const mergedSchema = await context.loadSchema([schema1, schema2]);
+
+    const typeMap = mergedSchema.getTypeMap();
+
+    expect(typeMap['Mutation']).toBeDefined();
+    expect(typeMap['DateTime']).toBeDefined();
+    expect(typeMap['User']).toBeDefined();
+  });
+});