feat: expect header exists or not

src/test.ts

@@ -123,6 +123,58 @@ export class Test extends Request {
     return this;
   }
 
+  /**
+   * UnExpectations:
+   *
+   *   .unexpectHeader('Content-Type')
+   *   .unexpectHeader('Content-Type', fn)
+   */
+  unexpectHeader(name: string, fn?: CallbackFunction) {
+    if (typeof fn === 'function') {
+      this.end(fn);
+    }
+
+    // header
+    if (typeof name === 'string') {
+      this._asserts.push(this._unexpectHeader.bind(this, name));
+    }
+    return this;
+  }
+
+  /**
+   * Expectations:
+   *
+   *   .expectHeader('Content-Type')
+   *   .expectHeader('Content-Type', fn)
+   */
+  expectHeader(name: string, fn?: CallbackFunction) {
+    if (typeof fn === 'function') {
+      this.end(fn);
+    }
+
+    // header
+    if (typeof name === 'string') {
+      this._asserts.push(this._expectHeader.bind(this, name));
+    }
+    return this;
+  }
+
+  _unexpectHeader(name: string, res: Response) {
+    const actual = res.headers[name.toLowerCase()];
+    if (actual) {
+      return new AssertError('unexpected "' + name + '" header field, got "' + actual + '"',
+        name, actual,
+      );
+    }
+  }
+
+  _expectHeader(name: string, res: Response) {
+    const actual = res.headers[name.toLowerCase()];
+    if (!actual) {
+      return new AssertError('expected "' + name + '" header field', name, actual);
+    }
+  }
+
   /**
    * Defer invoking superagent's `.end()` until
    * the server is listening.

test/supertest.test.ts

@@ -360,6 +360,67 @@ describe('request(app)', function() {
     });
   });
 
+  describe('.expectHeader(name, fn)', function() {
+    it('should expect header exists', function(done) {
+      const app = express();
+
+      app.get('/', function(_req, res) {
+        res.setHeader('Foo-Bar', 'ok');
+        res.send('hey');
+      });
+
+      request(app)
+        .get('/')
+        .expect(200)
+        .expectHeader('Foo-Bar')
+        .expectHeader('content-type')
+        .end(done);
+    });
+
+    it('should expect header exists with callback', function(done) {
+      const app = express();
+
+      app.get('/', function(_req, res) {
+        res.setHeader('Foo-Bar', 'ok');
+        res.send('hey');
+      });
+
+      request(app)
+        .get('/')
+        .expect(200)
+        .expectHeader('Foo-Bar', done);
+    });
+  });
+
+  describe('.unexpectHeader(name, fn)', function() {
+    it('should expect header not exists', function(done) {
+      const app = express();
+
+      app.get('/', function(_req, res) {
+        res.send('hey');
+      });
+
+      request(app)
+        .get('/')
+        .expect(200)
+        .unexpectHeader('Foo-Bar')
+        .end(done);
+    });
+
+    it('should expect header not exists with callback', function(done) {
+      const app = express();
+
+      app.get('/', function(_req, res) {
+        res.send('hey');
+      });
+
+      request(app)
+        .get('/')
+        .expect(200)
+        .unexpectHeader('Foo-Bar', done);
+    });
+  });
+
   describe('.expect(status[, fn])', function() {
     it('should assert the response status', function(done) {
       const app = express();