httpmock 
Easy mocking of http responses from external resources.
Install
Currently supports Go 1.7 - 1.15.
v1 branch has to be used instead of master.
Using go modules (aka. go mod)
In your go files, simply use:
import "github.com/jarcoal/httpmock"
Then next go mod tidy or go test invocation will automatically populate your go.mod with the last httpmock release, now 
Note you can use go mod vendor to vendor your dependencies.
Using $GOPATH
v1 branch is configured as the default branch in github, so:
go get github.com/jarcoal/httpmock
automatically downloads the v1 branch in $GOPATH/src. Then in your go files use:
import "github.com/jarcoal/httpmock"
Vendoring, using govendor for example
When vendoring is used, v1 branch has to be specified. Two choices here:
- preferred way:
then in go files:govendor fetch github.com/jarcoal/httpmock@v1import "github.com/jarcoal/httpmock"
- old way (before
v1was set as default branch), use gopkg to read fromv1branch:
then in go files:govendor fetch gopkg.in/jarcoal/httpmock.v1import "gopkg.in/jarcoal/httpmock.v1"
Usage
Simple Example:
func TestFetchArticles(t *testing.T) {
httpmock.Activate()
defer httpmock.DeactivateAndReset()
// Exact URL match
httpmock.RegisterResponder("GET", "https://api.mybiz.com/articles",
httpmock.NewStringResponder(200, `[{"id": 1, "name": "My Great Article"}]`))
// Regexp match (could use httpmock.RegisterRegexpResponder instead)
httpmock.RegisterResponder("GET", `=~^https://api\.mybiz\.com/articles/id/\d+\z`,
httpmock.NewStringResponder(200, `{"id": 1, "name": "My Great Article"}`))
// do stuff that makes a request to articles
...
// get count info
httpmock.GetTotalCallCount()
// get the amount of calls for the registered responder
info := httpmock.GetCallCountInfo()
info["GET https://api.mybiz.com/articles"] // number of GET calls made to https://api.mybiz.com/articles
info["GET https://api.mybiz.com/articles/id/12"] // number of GET calls made to https://api.mybiz.com/articles/id/12
info[`GET =~^https://api\.mybiz\.com/articles/id/\d+\z`] // number of GET calls made to https://api.mybiz.com/articles/id/<any-number>
}
Advanced Example:
func TestFetchArticles(t *testing.T) {
httpmock.Activate()
defer httpmock.DeactivateAndReset()
// our database of articles
articles := make([]map[string]interface{}, 0)
// mock to list out the articles
httpmock.RegisterResponder("GET", "https://api.mybiz.com/articles",
func(req *http.Request) (*http.Response, error) {
resp, err := httpmock.NewJsonResponse(200, articles)
if err != nil {
return httpmock.NewStringResponse(500, ""), nil
}
return resp, nil
},
)
// return an article related to the request with the help of regexp submatch (\d+)
httpmock.RegisterResponder("GET", `=~^https://api\.mybiz\.com/articles/id/(\d+)\z`,
func(req *http.Request) (*http.Response, error) {
// Get ID from request
id := httpmock.MustGetSubmatchAsUint(req, 1) // 1=first regexp submatch
return httpmock.NewJsonResponse(200, map[string]interface{}{
"id": id,
"name": "My Great Article",
})
},
)
// mock to add a new article
httpmock.RegisterResponder("POST", "https://api.mybiz.com/articles",
func(req *http.Request) (*http.Response, error) {
article := make(map[string]interface{})
if err := json.NewDecoder(req.Body).Decode(&article); err != nil {
return httpmock.NewStringResponse(400, ""), nil
}
articles = append(articles, article)
resp, err := httpmock.NewJsonResponse(200, article)
if err != nil {
return httpmock.NewStringResponse(500, ""), nil
}
return resp, nil
},
)
// do stuff that adds and checks articles
}
Algorithm
When GET http://example.tld/some/path?b=12&a=foo&a=bar request is caught, all standard responders are checked against the following URL or paths, the first match stops the search:
http://example.tld/some/path?b=12&a=foo&a=bar(original URL)http://example.tld/some/path?a=bar&a=foo&b=12(sorted query params)http://example.tld/some/path(without query params)/some/path?b=12&a=foo&a=bar(original URL without scheme and host)/some/path?a=bar&a=foo&b=12(same, but sorted query params)/some/path(path only)
If no standard responder matched, the regexp responders are checked, in the same order, the first match stops the search.
Ginkgo Example:
// article_suite_test.go
import (
// ...
"github.com/jarcoal/httpmock"
)
// ...
var _ = BeforeSuite(func() {
// block all HTTP requests
httpmock.Activate()
})
var _ = BeforeEach(func() {
// remove any mocks
httpmock.Reset()
})
var _ = AfterSuite(func() {
httpmock.DeactivateAndReset()
})
// article_test.go
import (
// ...
"github.com/jarcoal/httpmock"
)
var _ = Describe("Articles", func() {
It("returns a list of articles", func() {
httpmock.RegisterResponder("GET", "https://api.mybiz.com/articles.json",
httpmock.NewStringResponder(200, `[{"id": 1, "name": "My Great Article"}]`))
// do stuff that makes a request to articles.json
})
})
Ginkgo + Resty Example:
// article_suite_test.go
import (
// ...
"github.com/jarcoal/httpmock"
"github.com/go-resty/resty"
)
// ...
var _ = BeforeSuite(func() {
// block all HTTP requests
httpmock.ActivateNonDefault(resty.DefaultClient.GetClient())
})
var _ = BeforeEach(func() {
// remove any mocks
httpmock.Reset()
})
var _ = AfterSuite(func() {
httpmock.DeactivateAndReset()
})
// article_test.go
import (
// ...
"github.com/jarcoal/httpmock"
"github.com/go-resty/resty"
)
var _ = Describe("Articles", func() {
It("returns a list of articles", func() {
fixture := `{"status":{"message": "Your message", "code": 200}}`
responder := httpmock.NewStringResponder(200, fixture)
fakeUrl := "https://api.mybiz.com/articles.json"
httpmock.RegisterResponder("GET", fakeUrl, responder)
// fetch the article into struct
articleObject := &models.Article{}
_, err := resty.R().SetResult(articleObject).Get(fakeUrl)
// do stuff with the article object ...
})
})
