example-hello-world

This is a very basic Pact example, demonstrating the simplest use of a Pact Consumer

Mock provider setup

To create a Pact, we first need to define a relationship between Consumer and Provider.

This gives a mock Provider, which our Consumer can interact with.

js-v2

// Configure our Pact mock Provider
const mockProvider = new Pact({
  consumer: "BearServiceClient",
  provider: "BearService",
  cors: true,
  dir: "./output/pacts",
});

js-jest-pact-v2

// Configure our Pact mock Provider
pactWith(
  {
    consumer: "BearServiceClient",
    provider: "BearService",
    dir: "./output/pacts",
  },
  (mockProvider) => {

python-v2

# (1) Configure our Pact mock Provider
mock_provider = Consumer("BearServiceClient").has_pact_with(
    Provider("BearService"),
    host_name=PACT_MOCK_HOST,
    port=PACT_MOCK_PORT,
    pact_dir=PACT_DIR,
    log_dir=LOG_DIR,
)

js-v3

// Configure our Pact mock Provider
const mockProvider = new PactV3({
  consumer: "BearServiceClient",
  provider: "BearService",
  cors: true,
  dir: "./output/pacts",
});

js-jest-pact-v3

// Configure our Pact mock Provider
pactWith(
  {
    consumer: "BearServiceClient",
    provider: "BearService",
    dir: "./output/pacts",
  },

Pact creation

Each Pact is declared in a "given, when, then" style.

Following the "arrange, act, assert" pattern, we:

• arrange the expected interactions
• act on the consumer to perform the interaction
• assert that the mock provider received the specific interaction

js-v2

// Arrange: declare our expected interactions
const expectedResponse = {
  name: "Polar",
  colour: "White",
};

await mockProvider.addInteraction({
  state: "There are some bears",
  uponReceiving: "A request for the Bear species with id 1",
  willRespondWith: {
    status: 200,
    body: expectedResponse,
  },
  withRequest: {
    method: "GET",
    path: "/species/1",
  },
});

// Act: make the Consumer interact with the mock Provider
const api = new BearConsumer(mockProvider.mockService.baseUrl);
const bear = await api.getSpecies(1);

// Assert: check the result is as expected
expect(bear).to.deep.equal(new BearSpecies("Polar", "White"));

js-jest-pact-v2

describe("Test Bear species endpoint", () => {
  const expectedResponse = {
    name: "Polar",
    colour: "White",
  };

  // Arrange: declare our expected interactions
  beforeEach(() =>
    mockProvider.addInteraction({
      state: "There are some bears",
      uponReceiving: "A request for the Bear species with id 1",
      withRequest: {
        method: "GET",
        path: "/species/1",
      },
      willRespondWith: {
        status: 200,
        body: expectedResponse,
      },
    })
  );

  // Act: make the Consumer interact with the mock Provider
  it("Returns a Bear species", () => {
    return client.getSpecies(1).then((resp) => {
      // Assert: check the result is as expected
      expect(resp).toEqual(expectedResponse);
    });
  });
});

python-v2

# Arrange: declare our expected interactions
(
    mock_provider.given("There are some bears")
    .upon_receiving("A request for the Bear species with id 1")
    .with_request("GET", "/species/1")
    .will_respond_with(200, body=expected)
)

with mock_provider:
    # Act: make the Consumer interact with the mock Provider
    species = consumer.get_species(1)

    # Assert: check the result is as expected
    # In this case the mock Provider will have returned a valid response
    assert species.name == "Polar"
    assert species.colour == "White"

    # Make sure that all interactions defined occurred
    mock_provider.verify()

js-v3

// Arrange: declare our expected interactions
const expectedResponse = {
  name: "Polar",
  colour: "White",
};

mockProvider
  .given("There are some bears")
  .uponReceiving("A request for the Bear species with id 1")
  .withRequest({
    method: "GET",
    path: "/species/1",
  })
  .willRespondWith({
    status: 200,
    body: { ...expectedResponse },
  });

return await mockProvider.executeTest(async (mockserver) => {
  // Act: make the Consumer interact with the mock Provider
  const api = new BearConsumer(mockserver.url);
  const bear = await api.getSpecies(1);

  // Assert: check the result is as expected
  expect(bear).to.deep.equal(expectedResponse);
});

js-jest-pact-v3

const expectedResponse = {
  name: "Polar",
  colour: "White",
};

// Arrange: declare our expected interactions
beforeEach(() =>
  provider
    .given("There are some bears")
    .uponReceiving("A request for the Bear species with id 1")
    .withRequest({
      method: "GET",
      path: "/species/1",
    })
    .willRespondWith({
      status: 200,
      body: { ...expectedResponse },
    })
);

// Act: make the Consumer interact with the mock Provider
execute("Returns a Bear species", (mockserver) =>
  new BearConsumer(mockserver.url).getSpecies(1).then((resp) => {
    // Assert: check the result is as expected
    expect(resp).toEqual(expectedResponse);
  })
);

Something else

Some other code snippets would go here when we have some

None available

TODO: No code snippets available for this section

Pacts

v2

{
  "consumer": {
    "name": "BearServiceClient"
  },
  "provider": {
    "name": "BearService"
  },
  "interactions": [
    {
      "description": "A request for the Bear species with id 1",
      "providerState": "There are some bears",
      "request": {
        "method": "GET",
        "path": "/species/1"
      },
      "response": {
        "status": 200,
        "headers": {},
        "body": {
          "name": "Polar",
          "colour": "White"
        }
      }
    }
  ],
  "metadata": {
    "pactSpecification": {
      "version": "2.0.0"
    }
  }
}

v2-v3 diff

--- v2
+++ v3
@@ -8,7 +8,11 @@
   "interactions": [
     {
       "description": "A request for the Bear species with id 1",
-      "providerState": "There are some bears",
+      "providerStates": [
+        {
+          "name": "There are some bears"
+        }
+      ],
       "request": {
         "method": "GET",
         "path": "/species/1"
@@ -25,7 +29,7 @@
   ],
   "metadata": {
     "pactSpecification": {
-      "version": "2.0.0"
+      "version": "3.0.0"
     }
   }
 }

v3

{
  "consumer": {
    "name": "BearServiceClient"
  },
  "provider": {
    "name": "BearService"
  },
  "interactions": [
    {
      "description": "A request for the Bear species with id 1",
      "providerStates": [
        {
          "name": "There are some bears"
        }
      ],
      "request": {
        "method": "GET",
        "path": "/species/1"
      },
      "response": {
        "status": 200,
        "headers": {},
        "body": {
          "name": "Polar",
          "colour": "White"
        }
      }
    }
  ],
  "metadata": {
    "pactSpecification": {
      "version": "3.0.0"
    }
  }
}