From 750c11e2d96213e7d03f06086a3c2e95d70c4837 Mon Sep 17 00:00:00 2001
From: Vincenzo Chianese <vincenz.chianese@icloud.com>
Date: Sat, 25 May 2019 12:01:42 -0400
Subject: [PATCH 01/12] feat: make generator simple

---
 packages/cli/src/commands/mock.ts             | 47 ++++++++++++-------
 .../src/mocker/generator/IExampleGenerator.ts |  4 --
 .../generator/JSONSchemaExampleGenerator.ts   | 19 ++------
 3 files changed, 32 insertions(+), 38 deletions(-)
 delete mode 100644 packages/http/src/mocker/generator/IExampleGenerator.ts

diff --git a/packages/cli/src/commands/mock.ts b/packages/cli/src/commands/mock.ts
index 294132d3a..d198555fc 100644
--- a/packages/cli/src/commands/mock.ts
+++ b/packages/cli/src/commands/mock.ts
@@ -1,4 +1,5 @@
 import { Command } from '@oclif/command';
+import * as cluster from 'cluster';
 import * as signale from 'signale';
 import { ARGS, FLAGS } from '../const/options';
 import { createServer } from '../util/createServer';
@@ -11,33 +12,43 @@ export default class Server extends Command {
   public async run() {
     const signaleInteractiveInstance = new signale.Signale({ interactive: true });
 
-    signaleInteractiveInstance.await('Starting Prism…');
-
     const {
       flags: { port, dynamic },
       args: { spec },
     } = this.parse(Server);
 
-    if (true || dynamic) {
-      signale.star('Dynamic example generation enabled.');
-    }
-
-    const server = createServer(spec, { mock: { dynamic: true || dynamic } });
-    try {
-      const address = await server.listen(port);
+    if (cluster.isMaster) {
+      signaleInteractiveInstance.await('Starting Prism…');
 
-      if (server.prism.resources.length === 0) {
-        signaleInteractiveInstance.fatal('No operations found in the current file.');
-        this.exit(1);
+      if (true || dynamic) {
+        signale.star('Dynamic example generation enabled.');
       }
 
-      signaleInteractiveInstance.success(`Prism is listening on ${address}`);
-
-      server.prism.resources.forEach(resource => {
-        signale.note(`${resource.method.toUpperCase().padEnd(10)} ${address}${resource.path}`);
+      cluster.setupMaster({
+        silent: true,
       });
-    } catch (e) {
-      signaleInteractiveInstance.fatal(e.message);
+
+      const worker = cluster.fork();
+
+      if (worker.process.stdout) worker.process.stdout.pipe(process.stdout);
+    } else {
+      const server = createServer(spec, { mock: { dynamic: true || dynamic } });
+      try {
+        const address = await server.listen(port);
+
+        if (server.prism.resources.length === 0) {
+          signaleInteractiveInstance.fatal('No operations found in the current file.');
+          this.exit(1);
+        }
+
+        signaleInteractiveInstance.success(`Prism is listening on ${address}`);
+
+        server.prism.resources.forEach(resource => {
+          signale.note(`${resource.method.toUpperCase().padEnd(10)} ${address}${resource.path}`);
+        });
+      } catch (e) {
+        signaleInteractiveInstance.fatal(e.message);
+      }
     }
   }
 }
diff --git a/packages/http/src/mocker/generator/IExampleGenerator.ts b/packages/http/src/mocker/generator/IExampleGenerator.ts
deleted file mode 100644
index 073136d43..000000000
--- a/packages/http/src/mocker/generator/IExampleGenerator.ts
+++ /dev/null
@@ -1,4 +0,0 @@
-// @todo S is Schema interface (not defined yet)
-export interface IExampleGenerator<S = unknown> {
-  generate(schema: S, mediaType: string): Promise<string>;
-}
diff --git a/packages/http/src/mocker/generator/JSONSchemaExampleGenerator.ts b/packages/http/src/mocker/generator/JSONSchemaExampleGenerator.ts
index c00770001..e11d2d2fd 100644
--- a/packages/http/src/mocker/generator/JSONSchemaExampleGenerator.ts
+++ b/packages/http/src/mocker/generator/JSONSchemaExampleGenerator.ts
@@ -1,7 +1,5 @@
 // @ts-ignore
 import * as jsf from '@stoplight/json-schema-faker';
-import { cloneDeep } from 'lodash';
-import { IExampleGenerator } from './IExampleGenerator';
 
 jsf.option({
   failOnInvalidTypes: false,
@@ -16,19 +14,8 @@ jsf.option({
   maxLength: 100,
 });
 
-export class JSONSchemaExampleGenerator implements IExampleGenerator {
-  public async generate(schema: unknown, mediaType: string): Promise<string> {
-    const example = await jsf.resolve(cloneDeep(schema));
-    return this.transform(mediaType, example);
-  }
-
-  private transform(mediaType: string, input: object): string {
-    switch (mediaType) {
-      case 'application/json':
-        return JSON.stringify(input);
-
-      default:
-        throw new Error(`Unknown media type '${mediaType}'`);
-    }
+export class JSONSchemaExampleGenerator {
+  public async generate(source: unknown): Promise<unknown> {
+    return jsf.resolve(source);
   }
 }

From 8e0fcaf2d0b567492aee22c8941a911c76380810 Mon Sep 17 00:00:00 2001
From: Vincenzo Chianese <vincenz.chianese@icloud.com>
Date: Sat, 25 May 2019 12:59:17 -0400
Subject: [PATCH 02/12] chore: undo stupid cluster stuff

---
 packages/cli/src/commands/mock.ts | 45 ++++++++++++-------------------
 1 file changed, 17 insertions(+), 28 deletions(-)

diff --git a/packages/cli/src/commands/mock.ts b/packages/cli/src/commands/mock.ts
index d198555fc..07bc3a897 100644
--- a/packages/cli/src/commands/mock.ts
+++ b/packages/cli/src/commands/mock.ts
@@ -1,5 +1,4 @@
 import { Command } from '@oclif/command';
-import * as cluster from 'cluster';
 import * as signale from 'signale';
 import { ARGS, FLAGS } from '../const/options';
 import { createServer } from '../util/createServer';
@@ -17,38 +16,28 @@ export default class Server extends Command {
       args: { spec },
     } = this.parse(Server);
 
-    if (cluster.isMaster) {
-      signaleInteractiveInstance.await('Starting Prism…');
+    signaleInteractiveInstance.await('Starting Prism…');
 
-      if (true || dynamic) {
-        signale.star('Dynamic example generation enabled.');
-      }
-
-      cluster.setupMaster({
-        silent: true,
-      });
-
-      const worker = cluster.fork();
+    if (true || dynamic) {
+      signale.star('Dynamic example generation enabled.');
+    }
 
-      if (worker.process.stdout) worker.process.stdout.pipe(process.stdout);
-    } else {
-      const server = createServer(spec, { mock: { dynamic: true || dynamic } });
-      try {
-        const address = await server.listen(port);
+    const server = createServer(spec, { mock: { dynamic: true || dynamic } });
+    try {
+      const address = await server.listen(port);
 
-        if (server.prism.resources.length === 0) {
-          signaleInteractiveInstance.fatal('No operations found in the current file.');
-          this.exit(1);
-        }
+      if (server.prism.resources.length === 0) {
+        signaleInteractiveInstance.fatal('No operations found in the current file.');
+        this.exit(1);
+      }
 
-        signaleInteractiveInstance.success(`Prism is listening on ${address}`);
+      signaleInteractiveInstance.success(`Prism is listening on ${address}`);
 
-        server.prism.resources.forEach(resource => {
-          signale.note(`${resource.method.toUpperCase().padEnd(10)} ${address}${resource.path}`);
-        });
-      } catch (e) {
-        signaleInteractiveInstance.fatal(e.message);
-      }
+      server.prism.resources.forEach(resource => {
+        signale.note(`${resource.method.toUpperCase().padEnd(10)} ${address}${resource.path}`);
+      });
+    } catch (e) {
+      signaleInteractiveInstance.fatal(e.message);
     }
   }
 }

From 0a8117bbd2de5e26270c755aa2b3e53cd3e7b930 Mon Sep 17 00:00:00 2001
From: Vincenzo Chianese <vincenz.chianese@icloud.com>
Date: Sat, 25 May 2019 13:31:14 -0400
Subject: [PATCH 03/12] refactor: lower down generator responsibilities

---
 .../src/__tests__/server.oas.spec.ts          |  6 +--
 packages/http-server/src/server.ts            |  2 +-
 .../http-prism-instance.spec.ts.snap          |  1 +
 .../src/__tests__/http-prism-instance.spec.ts | 20 +++++---
 packages/http/src/index.ts                    |  5 +-
 packages/http/src/mocker/HttpMocker.ts        | 17 +++----
 .../src/mocker/__tests__/HttpMocker.spec.ts   | 37 ++++++++------
 .../__snapshots__/HttpMocker.spec.ts.snap     | 10 ----
 .../__snapshots__/functional.spec.ts.snap     | 22 ++++++--
 .../src/mocker/__tests__/functional.spec.ts   | 10 ++--
 ...chemaExampleGenerator.ts => JSONSchema.ts} |  7 ++-
 .../generator/__tests__/JSONSchema.spec.ts    | 34 +++++++++++++
 .../JSONSchemaExampleGenerator.spec.ts        | 50 -------------------
 .../JSONSchemaExampleGenerator.spec.ts.snap   |  3 --
 14 files changed, 110 insertions(+), 114 deletions(-)
 rename packages/http/src/mocker/generator/{JSONSchemaExampleGenerator.ts => JSONSchema.ts} (70%)
 create mode 100644 packages/http/src/mocker/generator/__tests__/JSONSchema.spec.ts
 delete mode 100644 packages/http/src/mocker/generator/__tests__/JSONSchemaExampleGenerator.spec.ts
 delete mode 100644 packages/http/src/mocker/generator/__tests__/__snapshots__/JSONSchemaExampleGenerator.spec.ts.snap

diff --git a/packages/http-server/src/__tests__/server.oas.spec.ts b/packages/http-server/src/__tests__/server.oas.spec.ts
index 0fe60d834..af16650ec 100644
--- a/packages/http-server/src/__tests__/server.oas.spec.ts
+++ b/packages/http-server/src/__tests__/server.oas.spec.ts
@@ -217,10 +217,10 @@ describe.each([['petstore.oas2.json'], ['petstore.oas3.json']])('server %s', fil
     // accorging to the schema
 
     const expectedValues = {
-      'x-rate-limit': file === 'petstore.oas3.json' ? 1000 : expect.any(String),
-      'x-stats': file === 'petstore.oas3.json' ? 1500 : expect.any(String),
+      'x-rate-limit': file === 'petstore.oas3.json' ? 1000 : expect.any(Number),
+      'x-stats': file === 'petstore.oas3.json' ? 1500 : expect.any(Number),
       'x-expires-after': expect.any(String),
-      'x-strange-header': file === 'petstore.oas3.json' ? 'string' : '{}',
+      'x-strange-header': file === 'petstore.oas3.json' ? 'string' : {},
     };
 
     for (const headerName of Object.keys(expectedValues)) {
diff --git a/packages/http-server/src/server.ts b/packages/http-server/src/server.ts
index d83008ceb..db72fc1d4 100644
--- a/packages/http-server/src/server.ts
+++ b/packages/http-server/src/server.ts
@@ -71,7 +71,7 @@ const replyHandler = <LoaderInput>(
           reply.headers(output.headers);
         }
 
-        reply.serializer((payload: unknown) => payload).send(output.body);
+        reply.send(output.body);
       } else {
         reply.code(500).send('Unable to find any decent response for the current request.');
       }
diff --git a/packages/http/src/__tests__/__snapshots__/http-prism-instance.spec.ts.snap b/packages/http/src/__tests__/__snapshots__/http-prism-instance.spec.ts.snap
index f675e8e5b..31c644d9b 100644
--- a/packages/http/src/__tests__/__snapshots__/http-prism-instance.spec.ts.snap
+++ b/packages/http/src/__tests__/__snapshots__/http-prism-instance.spec.ts.snap
@@ -15,6 +15,7 @@ Object {
     },
   },
   "output": Object {
+    "body": Anything,
     "headers": Object {
       "Content-type": "application/json",
     },
diff --git a/packages/http/src/__tests__/http-prism-instance.spec.ts b/packages/http/src/__tests__/http-prism-instance.spec.ts
index a66b52757..5abb7d36f 100644
--- a/packages/http/src/__tests__/http-prism-instance.spec.ts
+++ b/packages/http/src/__tests__/http-prism-instance.spec.ts
@@ -1,6 +1,5 @@
 import { IPrism } from '@stoplight/prism-core';
 import { IHttpOperation } from '@stoplight/types/http-spec';
-import { omit } from 'lodash';
 import { relative, resolve } from 'path';
 import { createInstance, IHttpConfig, IHttpRequest, IHttpResponse, ProblemJsonError } from '../';
 import { forwarder } from '../forwarder';
@@ -47,15 +46,22 @@ describe('Http Prism Instance function tests', () => {
         },
       },
     });
-    const parsedBody = JSON.parse(response!.output!.body);
+
+    const parsedBody = response!.output!.body;
+
     expect(parsedBody.length).toBeGreaterThan(0);
+
     parsedBody.forEach((element: any) => {
-      expect(typeof element.name).toEqual('string');
-      expect(Array.isArray(element.photoUrls)).toBeTruthy();
+      expect(typeof element.name).toBe('string');
+      expect(element.photoUrls).toBeInstanceOf(Array);
       expect(element.photoUrls.length).toBeGreaterThan(0);
     });
-    // because body is generated randomly
-    expect(omit(response, 'output.body')).toMatchSnapshot();
+
+    expect(response).toMatchSnapshot({
+      output: {
+        body: expect.anything(),
+      },
+    });
   });
 
   test('given route with invalid param should return a validation error', () => {
@@ -155,6 +161,6 @@ describe('Http Prism Instance function tests', () => {
     });
 
     expect(response.output).toBeDefined();
-    expect(typeof response.output!.body).toBe('string');
+    expect(response.output!.body).toBeInstanceOf(Array);
   });
 });
diff --git a/packages/http/src/index.ts b/packages/http/src/index.ts
index 284fad8ee..c11b4ad0e 100644
--- a/packages/http/src/index.ts
+++ b/packages/http/src/index.ts
@@ -1,9 +1,8 @@
 import { factory, FilesystemLoader, PartialPrismConfig } from '@stoplight/prism-core';
 import { IHttpOperation } from '@stoplight/types';
-
 import { forwarder } from './forwarder';
 import { HttpMocker } from './mocker';
-import { JSONSchemaExampleGenerator } from './mocker/generator/JSONSchemaExampleGenerator';
+import { generate } from './mocker/generator/JSONSchema';
 import { router } from './router';
 import {
   IHttpConfig,
@@ -31,7 +30,7 @@ const createInstance = <LoaderInput>(
       router,
       forwarder,
       validator,
-      mocker: new HttpMocker(new JSONSchemaExampleGenerator()),
+      mocker: new HttpMocker(generate),
     },
   )(config, overrides);
 };
diff --git a/packages/http/src/mocker/HttpMocker.ts b/packages/http/src/mocker/HttpMocker.ts
index 2e0385823..e912b1712 100644
--- a/packages/http/src/mocker/HttpMocker.ts
+++ b/packages/http/src/mocker/HttpMocker.ts
@@ -5,12 +5,13 @@ import * as caseless from 'caseless';
 import { fromPairs, keyBy, mapValues, toPairs } from 'lodash';
 import { IHttpConfig, IHttpOperationConfig, IHttpRequest, IHttpResponse, ProblemJsonError } from '../types';
 import { UNPROCESSABLE_ENTITY } from './errors';
-import { IExampleGenerator } from './generator/IExampleGenerator';
 import helpers from './negotiator/NegotiatorHelpers';
 import { IHttpNegotiationResult } from './negotiator/types';
 
+type GeneratorSignature = (f: unknown) => Promise<unknown>;
+
 export class HttpMocker implements IMocker<IHttpOperation, IHttpRequest, IHttpConfig, IHttpResponse> {
-  constructor(private _exampleGenerator: IExampleGenerator) {}
+  constructor(private _exampleGenerator: GeneratorSignature) {}
 
   public async mock({
     resource,
@@ -71,7 +72,7 @@ function isINodeExample(nodeExample: INodeExample | INodeExternalExample | undef
   return !!nodeExample && 'value' in nodeExample;
 }
 
-function computeMockedHeaders(headers: IHttpHeaderParam[], ex: IExampleGenerator): Promise<Dictionary<string>> {
+function computeMockedHeaders(headers: IHttpHeaderParam[], ex: GeneratorSignature): Promise<Dictionary<string>> {
   const headerWithPromiseValues = mapValues(keyBy(headers, h => h.name), async header => {
     if (header.content) {
       if (header.content.examples.length > 0) {
@@ -81,7 +82,7 @@ function computeMockedHeaders(headers: IHttpHeaderParam[], ex: IExampleGenerator
         }
       }
       if (header.content.schema) {
-        return ex.generate(header.content.schema, 'application/json');
+        return ex(header.content.schema);
       }
     }
     return 'string';
@@ -92,14 +93,12 @@ function computeMockedHeaders(headers: IHttpHeaderParam[], ex: IExampleGenerator
 
 async function computeBody(
   negotiationResult: Pick<IHttpNegotiationResult, 'schema' | 'mediaType' | 'bodyExample'>,
-  ex: IExampleGenerator,
+  ex: GeneratorSignature,
 ) {
   if (isINodeExample(negotiationResult.bodyExample) && negotiationResult.bodyExample.value !== undefined) {
-    return typeof negotiationResult.bodyExample.value === 'string'
-      ? negotiationResult.bodyExample.value
-      : JSON.stringify(negotiationResult.bodyExample.value);
+    return negotiationResult.bodyExample.value;
   } else if (negotiationResult.schema) {
-    return ex.generate(negotiationResult.schema, negotiationResult.mediaType);
+    return ex(negotiationResult.schema);
   }
   return undefined;
 }
diff --git a/packages/http/src/mocker/__tests__/HttpMocker.spec.ts b/packages/http/src/mocker/__tests__/HttpMocker.spec.ts
index 24d74ff93..6f42bc91c 100644
--- a/packages/http/src/mocker/__tests__/HttpMocker.spec.ts
+++ b/packages/http/src/mocker/__tests__/HttpMocker.spec.ts
@@ -1,12 +1,11 @@
 import { IHttpOperation, INodeExample } from '@stoplight/types';
 import { flatMap } from 'lodash';
 import { HttpMocker } from '../../mocker';
-import { JSONSchemaExampleGenerator } from '../../mocker/generator/JSONSchemaExampleGenerator';
+import * as JSONSchemaGenerator from '../../mocker/generator/JSONSchema';
 import helpers from '../negotiator/NegotiatorHelpers';
 
 describe('HttpMocker', () => {
-  const mockExampleGenerator = new JSONSchemaExampleGenerator();
-  const httpMocker = new HttpMocker(mockExampleGenerator);
+  const httpMocker = new HttpMocker(JSONSchemaGenerator.generate);
 
   afterEach(() => jest.restoreAllMocks());
 
@@ -120,7 +119,7 @@ describe('HttpMocker', () => {
         ).resolves.toMatchSnapshot();
       });
 
-      it('returns dynamic example', () => {
+      it('returns dynamic example', async () => {
         jest.spyOn(helpers, 'negotiateOptionsForValidRequest').mockReturnValue({
           code: '202',
           mediaType: 'test',
@@ -128,14 +127,15 @@ describe('HttpMocker', () => {
           headers: [],
         });
 
-        jest.spyOn(mockExampleGenerator, 'generate').mockResolvedValue('example value');
+        const response = await httpMocker.mock({
+          resource: mockResource,
+          input: mockInput,
+        });
 
-        return expect(
-          httpMocker.mock({
-            resource: mockResource,
-            input: mockInput,
-          }),
-        ).resolves.toMatchSnapshot();
+        return expect(response.body).toMatchObject({
+          name: expect.any(String),
+          surname: expect.any(String),
+        });
       });
     });
 
@@ -167,7 +167,7 @@ describe('HttpMocker', () => {
           schema: { type: 'string' },
         });
 
-        jest.spyOn(mockExampleGenerator, 'generate').mockResolvedValue('example value chelsea');
+        jest.spyOn(JSONSchemaGenerator, 'generate').mockResolvedValue('example value chelsea');
 
         return expect(
           httpMocker.mock({
@@ -181,10 +181,12 @@ describe('HttpMocker', () => {
     describe('when an example is defined', () => {
       describe('and dynamic flag is true', () => {
         describe('should generate a dynamic response', () => {
-          const generatedExample = JSON.stringify({ hello: 'world' });
+          const generatedExample = { hello: 'world' };
+
           beforeAll(() => {
-            jest.spyOn(mockExampleGenerator, 'generate').mockResolvedValue(generatedExample);
+            jest.spyOn(JSONSchemaGenerator, 'generate').mockResolvedValue(generatedExample);
           });
+
           afterAll(() => {
             jest.restoreAllMocks();
           });
@@ -196,7 +198,7 @@ describe('HttpMocker', () => {
               config: { mock: { dynamic: true } },
             });
 
-            expect(mockExampleGenerator.generate).toHaveBeenCalled();
+            expect(JSONSchemaGenerator.generate).not.toHaveBeenCalled();
             expect(response.body).toBeDefined();
 
             const allExamples = flatMap(mockResource.responses, res =>
@@ -206,7 +208,10 @@ describe('HttpMocker', () => {
             });
 
             allExamples.forEach(example => expect(response.body).not.toEqual(example));
-            expect(response.body).toBe(generatedExample);
+            expect(response.body).toMatchObject({
+              name: expect.any(String),
+              surname: expect.any(String),
+            });
           });
         });
       });
diff --git a/packages/http/src/mocker/__tests__/__snapshots__/HttpMocker.spec.ts.snap b/packages/http/src/mocker/__tests__/__snapshots__/HttpMocker.spec.ts.snap
index b614587bc..9b7e7a04b 100644
--- a/packages/http/src/mocker/__tests__/__snapshots__/HttpMocker.spec.ts.snap
+++ b/packages/http/src/mocker/__tests__/__snapshots__/HttpMocker.spec.ts.snap
@@ -24,16 +24,6 @@ Object {
 }
 `;
 
-exports[`HttpMocker mock() with valid negotiator response returns dynamic example 1`] = `
-Object {
-  "body": "example value",
-  "headers": Object {
-    "Content-type": "test",
-  },
-  "statusCode": 202,
-}
-`;
-
 exports[`HttpMocker mock() with valid negotiator response returns static example 1`] = `
 Object {
   "body": "hello",
diff --git a/packages/http/src/mocker/__tests__/__snapshots__/functional.spec.ts.snap b/packages/http/src/mocker/__tests__/__snapshots__/functional.spec.ts.snap
index fe431ad82..4c21bff22 100644
--- a/packages/http/src/mocker/__tests__/__snapshots__/functional.spec.ts.snap
+++ b/packages/http/src/mocker/__tests__/__snapshots__/functional.spec.ts.snap
@@ -2,7 +2,11 @@
 
 exports[`http mocker request is invalid returns 422 and static error response 1`] = `
 Object {
-  "body": "[{\\"message\\":\\"error\\"}]",
+  "body": Array [
+    Object {
+      "message": "error",
+    },
+  ],
   "headers": Object {
     "Content-type": "application/json",
   },
@@ -12,7 +16,13 @@ Object {
 
 exports[`http mocker request is valid HttpOperation contains example return lowest 2xx code and match response example to media type accepted by request 1`] = `
 Object {
-  "body": "[{\\"id\\":1,\\"completed\\":true,\\"name\\":\\"make prism\\"}]",
+  "body": Array [
+    Object {
+      "completed": true,
+      "id": 1,
+      "name": "make prism",
+    },
+  ],
   "headers": Object {
     "Content-type": "application/json",
   },
@@ -43,7 +53,13 @@ Object {
 
 exports[`http mocker request is valid given enforced example key should return application/json, 200 response 1`] = `
 Object {
-  "body": "[{\\"id\\":2,\\"completed\\":false,\\"name\\":\\"make bears\\"}]",
+  "body": Array [
+    Object {
+      "completed": false,
+      "id": 2,
+      "name": "make bears",
+    },
+  ],
   "headers": Object {
     "Content-type": "application/json",
   },
diff --git a/packages/http/src/mocker/__tests__/functional.spec.ts b/packages/http/src/mocker/__tests__/functional.spec.ts
index f37974dd0..d7d683d96 100644
--- a/packages/http/src/mocker/__tests__/functional.spec.ts
+++ b/packages/http/src/mocker/__tests__/functional.spec.ts
@@ -2,11 +2,11 @@ import { ISchema } from '@stoplight/types';
 import * as Ajv from 'ajv';
 
 import { httpOperations, httpRequests } from '../../__tests__/fixtures';
-import { JSONSchemaExampleGenerator } from '../generator/JSONSchemaExampleGenerator';
+import { generate } from '../generator/JSONSchema';
 import { HttpMocker } from '../index';
 
 describe('http mocker', () => {
-  const mocker = new HttpMocker(new JSONSchemaExampleGenerator());
+  const mocker = new HttpMocker(generate);
 
   describe('request is valid', () => {
     describe('given only enforced content type', () => {
@@ -229,7 +229,7 @@ describe('http mocker', () => {
           'Content-type': 'application/json',
           'x-todos-publish': expect.any(String),
         });
-        expect(validate(JSON.parse(response.body))).toBe(true);
+        expect(validate(response.body)).toBeTruthy();
       });
     });
   });
@@ -255,9 +255,9 @@ describe('http mocker', () => {
       });
 
       const ajv = new Ajv();
-      const validate = ajv.compile(httpOperations[1].responses[1].contents[0].schema as ISchema);
+      const validate = ajv.compile(httpOperations[1].responses[1].contents[0].schema!);
 
-      expect(validate(JSON.parse(response.body))).toBe(true);
+      expect(validate(response.body)).toBeTruthy();
     });
   });
 });
diff --git a/packages/http/src/mocker/generator/JSONSchemaExampleGenerator.ts b/packages/http/src/mocker/generator/JSONSchema.ts
similarity index 70%
rename from packages/http/src/mocker/generator/JSONSchemaExampleGenerator.ts
rename to packages/http/src/mocker/generator/JSONSchema.ts
index e11d2d2fd..34bee96e1 100644
--- a/packages/http/src/mocker/generator/JSONSchemaExampleGenerator.ts
+++ b/packages/http/src/mocker/generator/JSONSchema.ts
@@ -1,5 +1,6 @@
 // @ts-ignore
 import * as jsf from '@stoplight/json-schema-faker';
+import { cloneDeep } from 'lodash';
 
 jsf.option({
   failOnInvalidTypes: false,
@@ -14,8 +15,6 @@ jsf.option({
   maxLength: 100,
 });
 
-export class JSONSchemaExampleGenerator {
-  public async generate(source: unknown): Promise<unknown> {
-    return jsf.resolve(source);
-  }
+export async function generate(source: unknown): Promise<unknown> {
+  return jsf.resolve(cloneDeep(source));
 }
diff --git a/packages/http/src/mocker/generator/__tests__/JSONSchema.spec.ts b/packages/http/src/mocker/generator/__tests__/JSONSchema.spec.ts
new file mode 100644
index 000000000..661d111ed
--- /dev/null
+++ b/packages/http/src/mocker/generator/__tests__/JSONSchema.spec.ts
@@ -0,0 +1,34 @@
+import { generate } from '../JSONSchema';
+
+describe('JSONSchemaExampleGenerator', () => {
+  describe('generate()', () => {
+    it('generates dynamic example from schema', async () => {
+      const schema = {
+        type: 'object',
+        properties: {
+          name: { type: 'string', minLength: 1 },
+          email: { type: 'string', format: 'email' },
+        },
+        required: ['name', 'email'],
+      };
+
+      const instance = await generate(schema);
+      expect(instance).toHaveProperty('name');
+      expect(instance).toHaveProperty('email');
+    });
+
+    it('operates on sealed schema objects', () => {
+      const schema = {
+        type: 'object',
+        properties: {
+          name: { type: 'string' },
+        },
+        required: ['name'],
+      };
+
+      Object.defineProperty(schema.properties, 'name', { writable: false });
+
+      return expect(generate(schema)).resolves.toBeTruthy();
+    });
+  });
+});
diff --git a/packages/http/src/mocker/generator/__tests__/JSONSchemaExampleGenerator.spec.ts b/packages/http/src/mocker/generator/__tests__/JSONSchemaExampleGenerator.spec.ts
deleted file mode 100644
index 32cf2a5f4..000000000
--- a/packages/http/src/mocker/generator/__tests__/JSONSchemaExampleGenerator.spec.ts
+++ /dev/null
@@ -1,50 +0,0 @@
-import { JSONSchemaExampleGenerator } from '../JSONSchemaExampleGenerator';
-
-describe('JSONSchemaExampleGenerator', () => {
-  let jsonSchemaExampleGenerator: JSONSchemaExampleGenerator;
-
-  beforeEach(() => {
-    jsonSchemaExampleGenerator = new JSONSchemaExampleGenerator();
-  });
-
-  describe('generate()', () => {
-    it('generates dynamic example from schema', async () => {
-      const schema = {
-        type: 'object',
-        properties: {
-          name: { type: 'string', minLength: 1 },
-          email: { type: 'string', format: 'email' },
-        },
-        required: ['name', 'email'],
-      };
-
-      const example = await jsonSchemaExampleGenerator.generate(schema, 'application/json');
-      const instance = JSON.parse(example);
-
-      expect(instance.name).toMatch(/^.+$/);
-
-      // naive email check, should be enough
-      expect(instance.email).toMatch(/[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,4}/);
-    });
-
-    it('fails when media type is unknown', () => {
-      return expect(
-        jsonSchemaExampleGenerator.generate({}, 'non-existing/media-type'),
-      ).rejects.toThrowErrorMatchingSnapshot();
-    });
-
-    it('operates on sealed schema objects', () => {
-      const schema = {
-        type: 'object',
-        properties: {
-          name: { type: 'string' },
-        },
-        required: ['name'],
-      };
-
-      Object.defineProperty(schema.properties, 'name', { writable: false });
-
-      return expect(jsonSchemaExampleGenerator.generate(schema, 'application/json')).resolves.toBeTruthy();
-    });
-  });
-});
diff --git a/packages/http/src/mocker/generator/__tests__/__snapshots__/JSONSchemaExampleGenerator.spec.ts.snap b/packages/http/src/mocker/generator/__tests__/__snapshots__/JSONSchemaExampleGenerator.spec.ts.snap
deleted file mode 100644
index df626be35..000000000
--- a/packages/http/src/mocker/generator/__tests__/__snapshots__/JSONSchemaExampleGenerator.spec.ts.snap
+++ /dev/null
@@ -1,3 +0,0 @@
-// Jest Snapshot v1, https://goo.gl/fbAQLP
-
-exports[`JSONSchemaExampleGenerator generate() fails when media type is unknown 1`] = `"Unknown media type 'non-existing/media-type'"`;

From 77ab99fa9baa02f51d7befff37972a7aef8ff92c Mon Sep 17 00:00:00 2001
From: Vincenzo Chianese <vincenz.chianese@icloud.com>
Date: Sat, 25 May 2019 13:37:00 -0400
Subject: [PATCH 04/12] refactor: PayloadGenerator and put it in types

---
 packages/http/src/mocker/HttpMocker.ts | 17 +++++++++++------
 packages/http/src/types.ts             |  2 ++
 2 files changed, 13 insertions(+), 6 deletions(-)

diff --git a/packages/http/src/mocker/HttpMocker.ts b/packages/http/src/mocker/HttpMocker.ts
index e912b1712..e97e12a47 100644
--- a/packages/http/src/mocker/HttpMocker.ts
+++ b/packages/http/src/mocker/HttpMocker.ts
@@ -3,15 +3,20 @@ import { Dictionary, IHttpHeaderParam, IHttpOperation, INodeExample, INodeExtern
 
 import * as caseless from 'caseless';
 import { fromPairs, keyBy, mapValues, toPairs } from 'lodash';
-import { IHttpConfig, IHttpOperationConfig, IHttpRequest, IHttpResponse, ProblemJsonError } from '../types';
+import {
+  IHttpConfig,
+  IHttpOperationConfig,
+  IHttpRequest,
+  IHttpResponse,
+  PayloadGenerator,
+  ProblemJsonError,
+} from '../types';
 import { UNPROCESSABLE_ENTITY } from './errors';
 import helpers from './negotiator/NegotiatorHelpers';
 import { IHttpNegotiationResult } from './negotiator/types';
 
-type GeneratorSignature = (f: unknown) => Promise<unknown>;
-
 export class HttpMocker implements IMocker<IHttpOperation, IHttpRequest, IHttpConfig, IHttpResponse> {
-  constructor(private _exampleGenerator: GeneratorSignature) {}
+  constructor(private _exampleGenerator: PayloadGenerator) {}
 
   public async mock({
     resource,
@@ -72,7 +77,7 @@ function isINodeExample(nodeExample: INodeExample | INodeExternalExample | undef
   return !!nodeExample && 'value' in nodeExample;
 }
 
-function computeMockedHeaders(headers: IHttpHeaderParam[], ex: GeneratorSignature): Promise<Dictionary<string>> {
+function computeMockedHeaders(headers: IHttpHeaderParam[], ex: PayloadGenerator): Promise<Dictionary<string>> {
   const headerWithPromiseValues = mapValues(keyBy(headers, h => h.name), async header => {
     if (header.content) {
       if (header.content.examples.length > 0) {
@@ -93,7 +98,7 @@ function computeMockedHeaders(headers: IHttpHeaderParam[], ex: GeneratorSignatur
 
 async function computeBody(
   negotiationResult: Pick<IHttpNegotiationResult, 'schema' | 'mediaType' | 'bodyExample'>,
-  ex: GeneratorSignature,
+  ex: PayloadGenerator,
 ) {
   if (isINodeExample(negotiationResult.bodyExample) && negotiationResult.bodyExample.value !== undefined) {
     return negotiationResult.bodyExample.value;
diff --git a/packages/http/src/types.ts b/packages/http/src/types.ts
index 426ffc6ed..d01a2b05a 100644
--- a/packages/http/src/types.ts
+++ b/packages/http/src/types.ts
@@ -104,3 +104,5 @@ export class ProblemJsonError extends Error {
     Error.captureStackTrace(this, ProblemJsonError);
   }
 }
+
+export type PayloadGenerator = (f: unknown) => Promise<unknown>;

From 1270970ecd4ff44a1ccfb4efde14762ce20f19d9 Mon Sep 17 00:00:00 2001
From: Vincenzo Chianese <vincenz.chianese@icloud.com>
Date: Sat, 25 May 2019 14:29:35 -0400
Subject: [PATCH 05/12] chore: throw exception so that it's an
 application/problem-json

---
 packages/http-server/src/server.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/http-server/src/server.ts b/packages/http-server/src/server.ts
index db72fc1d4..b265a3443 100644
--- a/packages/http-server/src/server.ts
+++ b/packages/http-server/src/server.ts
@@ -73,7 +73,7 @@ const replyHandler = <LoaderInput>(
 
         reply.send(output.body);
       } else {
-        reply.code(500).send('Unable to find any decent response for the current request.');
+        throw new Error('Unable to find any decent response for the current request.');
       }
     } catch (e) {
       const status = 'status' in e ? e.status : 500;

From 7f41cf40e7dd6a8a6d88b4f377773d614d3ca6b0 Mon Sep 17 00:00:00 2001
From: Vincenzo Chianese <vincenz.chianese@icloud.com>
Date: Sat, 25 May 2019 14:44:38 -0400
Subject: [PATCH 06/12] test: prefer assertions to snapshots

---
 packages/http/src/__tests__/fixtures/index.ts | 20 +++++--------
 .../__snapshots__/functional.spec.ts.snap     | 30 -------------------
 .../src/mocker/__tests__/functional.spec.ts   | 10 +++++--
 3 files changed, 16 insertions(+), 44 deletions(-)

diff --git a/packages/http/src/__tests__/fixtures/index.ts b/packages/http/src/__tests__/fixtures/index.ts
index 7a9248571..6d1ad9bf3 100644
--- a/packages/http/src/__tests__/fixtures/index.ts
+++ b/packages/http/src/__tests__/fixtures/index.ts
@@ -40,13 +40,11 @@ export const httpOperations: IHttpOperation[] = [
             examples: [
               {
                 key: 'application/json',
-                value: [
-                  {
-                    id: 1,
-                    completed: true,
-                    name: 'make prism',
-                  },
-                ],
+                value: {
+                  id: 1,
+                  completed: true,
+                  name: 'make prism',
+                },
               },
               {
                 key: 'bear',
@@ -143,11 +141,9 @@ export const httpOperations: IHttpOperation[] = [
             examples: [
               {
                 key: 'application/json',
-                value: [
-                  {
-                    message: 'error',
-                  },
-                ],
+                value: {
+                  message: 'error',
+                },
               },
             ],
             encodings: [],
diff --git a/packages/http/src/mocker/__tests__/__snapshots__/functional.spec.ts.snap b/packages/http/src/mocker/__tests__/__snapshots__/functional.spec.ts.snap
index 4c21bff22..e041b5393 100644
--- a/packages/http/src/mocker/__tests__/__snapshots__/functional.spec.ts.snap
+++ b/packages/http/src/mocker/__tests__/__snapshots__/functional.spec.ts.snap
@@ -1,35 +1,5 @@
 // Jest Snapshot v1, https://goo.gl/fbAQLP
 
-exports[`http mocker request is invalid returns 422 and static error response 1`] = `
-Object {
-  "body": Array [
-    Object {
-      "message": "error",
-    },
-  ],
-  "headers": Object {
-    "Content-type": "application/json",
-  },
-  "statusCode": 422,
-}
-`;
-
-exports[`http mocker request is valid HttpOperation contains example return lowest 2xx code and match response example to media type accepted by request 1`] = `
-Object {
-  "body": Array [
-    Object {
-      "completed": true,
-      "id": 1,
-      "name": "make prism",
-    },
-  ],
-  "headers": Object {
-    "Content-type": "application/json",
-  },
-  "statusCode": 200,
-}
-`;
-
 exports[`http mocker request is valid HttpOperation contains example return lowest 2xx response and the first example matching the media type 1`] = `
 Object {
   "body": "<todo><name>Shopping</name><completed>false</completed></todo>",
diff --git a/packages/http/src/mocker/__tests__/functional.spec.ts b/packages/http/src/mocker/__tests__/functional.spec.ts
index d7d683d96..3aeb7a255 100644
--- a/packages/http/src/mocker/__tests__/functional.spec.ts
+++ b/packages/http/src/mocker/__tests__/functional.spec.ts
@@ -166,7 +166,12 @@ describe('http mocker', () => {
           input: httpRequests[0],
         });
 
-        expect(response).toMatchSnapshot();
+        expect(response.statusCode).toBe(200);
+        expect(response.body).toMatchObject({
+          completed: true,
+          id: 1,
+          name: 'make prism',
+        });
       });
 
       test('return lowest 2xx response and the first example matching the media type', async () => {
@@ -241,7 +246,8 @@ describe('http mocker', () => {
         input: httpRequests[1],
       });
 
-      expect(response).toMatchSnapshot();
+      expect(response.statusCode).toBe(422);
+      expect(response.body).toMatchObject({ message: 'error' });
     });
 
     test('returns 422 and dynamic error response', async () => {

From a060f1793db6ebdf73706c229eff84bbcc0b8fd6 Mon Sep 17 00:00:00 2001
From: Vincenzo Chianese <vincenz.chianese@icloud.com>
Date: Sat, 25 May 2019 14:54:19 -0400
Subject: [PATCH 07/12] docs: fix path to the CLI script

---
 CONTRIBUTING.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 0cd98dbc5..64b6e5277 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -34,7 +34,7 @@ Yarn is a package manager for your code, similar to npm. While you can use npm t
 2. Fork the [https://github.com/stoplightio/prism](https://github.com/stoplightio/prism) repo.
 3. Git clone your fork (i.e. `git clone https://github.com/<your-username>/prism.git`) to your machine.
 4. Run `yarn` to install dependencies and setup the project.
-5. Because [oclif](https://oclif.io) does not respect the provided `tsconfig`, you can't use the bin directly, but we provide a script for that: `cd packages && yarn cli mock openapi.yaml`
+5. Because [oclif](https://oclif.io) does not respect the provided `tsconfig`, you can't use the bin directly, but we provide a script for that: `cd packages/cli && yarn cli mock openapi.yaml`.
 6. Run `git checkout -b [name_of_your_new_branch]` to create a new branch for your work. To help build nicer changelogs, we have a convention for branch names. Please start your branch with either `feature/{branch-name}`, `chore/{branch-name}`, or `fix/{branch-name}`. For example, if I was adding a CLI, I would make my branch name: `feature/add-cli`.
 7. Make changes, write code and tests, etc. The fun stuff!
 8. Run `yarn test` to test your changes.

From e83a3f64a283814df9fd0f1fec9e900a60057346 Mon Sep 17 00:00:00 2001
From: Vincenzo Chianese <vincenz.chianese@icloud.com>
Date: Sat, 25 May 2019 14:55:15 -0400
Subject: [PATCH 08/12] docs: put the new simplified command

---
 CONTRIBUTING.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 64b6e5277..25b89905f 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -72,7 +72,7 @@ The best way to debug a Prism behavior is probably to attach your debugger to th
 ```bash
 cd packages/cli
 
-node --inspect-brk -r tsconfig-paths/register bin/run mock file.oas.yml
+yarn cli:debug mock file.oas.yml
 ```
 
 The application will wait for a debugger to be attached and break on the first line; from there, you can put your breakpoint here and there and help us debug the software!

From 7fca363758dc2e3d5187ffd8eec967670588d9b5 Mon Sep 17 00:00:00 2001
From: Vincenzo Chianese <vincenz.chianese@icloud.com>
Date: Sat, 25 May 2019 15:11:13 -0400
Subject: [PATCH 09/12] chore: do not publish on alpha we're doing stuff anyway
 there

---
 .circleci/config.yml | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/.circleci/config.yml b/.circleci/config.yml
index 6c0d06c7e..c6c99bb57 100644
--- a/.circleci/config.yml
+++ b/.circleci/config.yml
@@ -50,7 +50,7 @@ jobs:
       - run: echo "//registry.npmjs.org/:_authToken=$NPM_TOKEN" >> ~/.npmrc
       - run:
           name: Publish
-          command: yarn lerna publish from-git --github-release --yes --dist-tag alpha
+          command: yarn lerna publish from-git --github-release --yes
       - run:
           name: Create CLI binaries
           command: npx pkg --out-path ./cli-binaries ./packages/cli/

From 5b0c159048e9df842c793cf855888ef501afa76a Mon Sep 17 00:00:00 2001
From: Vincenzo Chianese <vincenz.chianese@icloud.com>
Date: Sat, 25 May 2019 15:41:15 -0400
Subject: [PATCH 10/12] test: rename test describe title

---
 packages/http/src/mocker/generator/__tests__/JSONSchema.spec.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/http/src/mocker/generator/__tests__/JSONSchema.spec.ts b/packages/http/src/mocker/generator/__tests__/JSONSchema.spec.ts
index 661d111ed..6ae699498 100644
--- a/packages/http/src/mocker/generator/__tests__/JSONSchema.spec.ts
+++ b/packages/http/src/mocker/generator/__tests__/JSONSchema.spec.ts
@@ -1,6 +1,6 @@
 import { generate } from '../JSONSchema';
 
-describe('JSONSchemaExampleGenerator', () => {
+describe('JSONSchema generator', () => {
   describe('generate()', () => {
     it('generates dynamic example from schema', async () => {
       const schema = {

From 9a8f91ddd470e16b750cf79ea3d210a8d0c44f10 Mon Sep 17 00:00:00 2001
From: Vincenzo Chianese <vincenz.chianese@icloud.com>
Date: Mon, 27 May 2019 11:53:02 +0200
Subject: [PATCH 11/12] refactor: return empty string if the generated object
 is empty

---
 packages/http-server/src/__tests__/server.oas.spec.ts | 2 +-
 packages/http/src/mocker/HttpMocker.ts                | 5 +++--
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/packages/http-server/src/__tests__/server.oas.spec.ts b/packages/http-server/src/__tests__/server.oas.spec.ts
index af16650ec..f141d1e67 100644
--- a/packages/http-server/src/__tests__/server.oas.spec.ts
+++ b/packages/http-server/src/__tests__/server.oas.spec.ts
@@ -220,7 +220,7 @@ describe.each([['petstore.oas2.json'], ['petstore.oas3.json']])('server %s', fil
       'x-rate-limit': file === 'petstore.oas3.json' ? 1000 : expect.any(Number),
       'x-stats': file === 'petstore.oas3.json' ? 1500 : expect.any(Number),
       'x-expires-after': expect.any(String),
-      'x-strange-header': file === 'petstore.oas3.json' ? 'string' : {},
+      'x-strange-header': 'string',
     };
 
     for (const headerName of Object.keys(expectedValues)) {
diff --git a/packages/http/src/mocker/HttpMocker.ts b/packages/http/src/mocker/HttpMocker.ts
index e97e12a47..c0c3b7291 100644
--- a/packages/http/src/mocker/HttpMocker.ts
+++ b/packages/http/src/mocker/HttpMocker.ts
@@ -2,7 +2,7 @@ import { IMocker, IMockerOpts } from '@stoplight/prism-core';
 import { Dictionary, IHttpHeaderParam, IHttpOperation, INodeExample, INodeExternalExample } from '@stoplight/types';
 
 import * as caseless from 'caseless';
-import { fromPairs, keyBy, mapValues, toPairs } from 'lodash';
+import { fromPairs, isEmpty, isObject, keyBy, mapValues, toPairs } from 'lodash';
 import {
   IHttpConfig,
   IHttpOperationConfig,
@@ -87,7 +87,8 @@ function computeMockedHeaders(headers: IHttpHeaderParam[], ex: PayloadGenerator)
         }
       }
       if (header.content.schema) {
-        return ex(header.content.schema);
+        const example = await ex(header.content.schema);
+        if (!(isObject(example) && isEmpty(example))) return example;
       }
     }
     return 'string';

From 9a80dcb5da3334f7c42ff1de60dd9dbe7576a932 Mon Sep 17 00:00:00 2001
From: Vincenzo Chianese <vincenz.chianese@icloud.com>
Date: Mon, 27 May 2019 15:14:16 +0200
Subject: [PATCH 12/12] chore: empty string

---
 packages/http-server/src/__tests__/server.oas.spec.ts | 2 +-
 packages/http/src/mocker/HttpMocker.ts                | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/packages/http-server/src/__tests__/server.oas.spec.ts b/packages/http-server/src/__tests__/server.oas.spec.ts
index f141d1e67..ac11f7cef 100644
--- a/packages/http-server/src/__tests__/server.oas.spec.ts
+++ b/packages/http-server/src/__tests__/server.oas.spec.ts
@@ -220,7 +220,7 @@ describe.each([['petstore.oas2.json'], ['petstore.oas3.json']])('server %s', fil
       'x-rate-limit': file === 'petstore.oas3.json' ? 1000 : expect.any(Number),
       'x-stats': file === 'petstore.oas3.json' ? 1500 : expect.any(Number),
       'x-expires-after': expect.any(String),
-      'x-strange-header': 'string',
+      'x-strange-header': '',
     };
 
     for (const headerName of Object.keys(expectedValues)) {
diff --git a/packages/http/src/mocker/HttpMocker.ts b/packages/http/src/mocker/HttpMocker.ts
index c0c3b7291..28defbcb5 100644
--- a/packages/http/src/mocker/HttpMocker.ts
+++ b/packages/http/src/mocker/HttpMocker.ts
@@ -91,7 +91,7 @@ function computeMockedHeaders(headers: IHttpHeaderParam[], ex: PayloadGenerator)
         if (!(isObject(example) && isEmpty(example))) return example;
       }
     }
-    return 'string';
+    return '';
   });
 
   return resolvePromiseInProps(headerWithPromiseValues);