go-vcr

go-vcr

go-vcr simplifies testing by recording your HTTP interactions and replaying them in future runs in order to provide fast, deterministic and accurate testing of your code.

go-vcr was inspired by the VCR library for Ruby.

Installation

Install go-vcr by executing the command below:

$ go get github.com/dnaeon/go-vcr/recorder

Usage

Here is a simple example of recording and replaying etcd HTTP interactions.

You can find other examples in the example directory of this repository as well.

package main

import (
	"log"
	"time"

	"github.com/dnaeon/go-vcr/recorder"

	"github.com/coreos/etcd/client"
	"golang.org/x/net/context"
)

func main() {
	// Start our recorder
	r, err := recorder.New("fixtures/etcd")
	if err != nil {
		log.Fatal(err)
	}
	defer r.Stop() // Make sure recorder is stopped once done with it

	// Create an etcd configuration using our transport
	cfg := client.Config{
		Endpoints:               []string{"http://127.0.0.1:2379"},
		HeaderTimeoutPerRequest: time.Second,
		Transport:               r, // Inject as transport!
	}

	// Create an etcd client using the above configuration
	c, err := client.New(cfg)
	if err != nil {
		log.Fatalf("Failed to create etcd client: %s", err)
	}

	// Get an example key from etcd
	etcdKey := "/foo"
	kapi := client.NewKeysAPI(c)
	resp, err := kapi.Get(context.Background(), etcdKey, nil)

	if err != nil {
		log.Fatalf("Failed to get etcd key %s: %s", etcdKey, err)
	}

	log.Printf("Successfully retrieved etcd key %s: %s", etcdKey, resp.Node.Value)
}

Custom Request Matching

During replay mode, You can customize the way incoming requests are matched against the recorded request/response pairs by defining a Matcher function. For example, the following matcher will match on method, URL and body:

r, err := recorder.New("fixtures/matchers")
if err != nil {
	log.Fatal(err)
}
defer r.Stop() // Make sure recorder is stopped once done with it

r.SetMatcher(func(r *http.Request, i cassette.Request) bool {
    var b bytes.Buffer
	if _, err := b.ReadFrom(r.Body); err != nil {
		return false
	}
	r.Body = ioutil.NopCloser(&b)
	return cassette.DefaultMatcher(r, i) && (b.String() == "" || b.String() == i.Body)
})

License

go-vcr is Open Source and licensed under the BSD License