feat: introduce new matchers feature

It is now possible to create a Responder based on Request
content (header or body for example), so not only on method and URL as
before.

Signed-off-by: Maxime Soulé <btik-git@scoubidou.com>

README.md

@@ -65,8 +65,7 @@ func TestFetchArticles(t *testing.T) {
         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`,
@@ -77,8 +76,7 @@ func TestFetchArticles(t *testing.T) {
         "id":   id,
         "name": "My Great Article",
       })
-    },
-  )
+    })
 
   // mock to add a new article
   httpmock.RegisterResponder("POST", "https://api.mybiz.com/articles",
@@ -95,8 +93,13 @@ func TestFetchArticles(t *testing.T) {
         return httpmock.NewStringResponse(500, ""), nil
       }
       return resp, nil
-    },
-  )
+    })
+
+  // mock to add a specific article, send a Bad Request response
+  // when the request body contains `"type":"toy"`
+  httpmock.RegisterMatcherResponder("POST", "https://api.mybiz.com/articles",
+    httpmock.BodyContainsString(`"type":"toy"`),
+    httpmock.NewStringResponder(400, `{"reason":"Invalid article type"}`))
 
   // do stuff that adds and checks articles
 }

export_test.go

@@ -0,0 +1,87 @@
+package httpmock
+
+import (
+	"io"
+	"net/http"
+	"reflect"
+	"sync/atomic"
+
+	"github.com/jarcoal/httpmock/internal"
+)
+
+var (
+	GetPackage     = getPackage
+	ExtractPackage = extractPackage
+	CalledFrom     = calledFrom
+)
+
+type (
+	MatchResponder  = matchResponder
+	MatchResponders = matchResponders
+)
+
+func init() {
+	atomic.AddInt64(&matcherID, 0xabcdef)
+}
+
+func GetIgnorePackages() map[string]bool {
+	return ignorePackages
+}
+
+// bodyCopyOnRead
+
+func NewBodyCopyOnRead(body io.ReadCloser) *bodyCopyOnRead { //nolint: revive
+	return &bodyCopyOnRead{body: body}
+}
+
+func (b *bodyCopyOnRead) Body() io.ReadCloser {
+	return b.body
+}
+
+func (b *bodyCopyOnRead) Buf() []byte {
+	return b.buf
+}
+
+func (b *bodyCopyOnRead) Rearm() {
+	b.rearm()
+}
+
+// matchRouteKey
+
+func NewMatchRouteKey(rk internal.RouteKey, name string) matchRouteKey { //nolint: revive
+	return matchRouteKey{RouteKey: rk, name: name}
+}
+
+// matchResponder
+
+func NewMatchResponder(matcher Matcher, resp Responder) matchResponder { //nolint: revive
+	return matchResponder{matcher: matcher, responder: resp}
+}
+
+func (mr matchResponder) ResponderPointer() uintptr {
+	return reflect.ValueOf(mr.responder).Pointer()
+}
+
+func (mr matchResponder) Matcher() Matcher {
+	return mr.matcher
+}
+
+// matchResponders
+
+func (mrs matchResponders) Add(mr matchResponder) matchResponders {
+	return mrs.add(mr)
+}
+
+func (mrs matchResponders) Remove(name string) matchResponders {
+	return mrs.remove(name)
+}
+
+func (mrs matchResponders) FindMatchResponder(req *http.Request) *matchResponder {
+	return mrs.findMatchResponder(req)
+}
+
+// Matcher
+
+func (m Matcher) FnPointer() uintptr {
+	return reflect.ValueOf(m.fn).Pointer()
+}

internal/error.go

@@ -12,7 +12,7 @@ var NoResponderFound = errors.New("no responder found") // nolint: revive
 // ErrorNoResponderFoundMistake encapsulates a NoResponderFound
 // error probably due to a user error on the method or URL path.
 type ErrorNoResponderFoundMistake struct {
-	Kind      string // "method" or "URL"
+	Kind      string // "method", "URL" or "matcher"
 	Orig      string // original wrong method/URL, without any matching responder
 	Suggested string // suggested method/URL with a matching responder
 }
@@ -26,6 +26,12 @@ func (e *ErrorNoResponderFoundMistake) Unwrap() error {
 
 // Error implements error interface.
 func (e *ErrorNoResponderFoundMistake) Error() string {
+	if e.Kind == "matcher" {
+		return fmt.Sprintf("%s despite %s",
+			NoResponderFound,
+			e.Suggested,
+		)
+	}
 	return fmt.Sprintf("%[1]s for %[2]s %[3]q, but one matches %[2]s %[4]q",
 		NoResponderFound,
 		e.Kind,

internal/error_test.go

@@ -14,8 +14,14 @@ func TestErrorNoResponderFoundMistake(t *testing.T) {
 		Orig:      "pipo",
 		Suggested: "BINGO",
 	}
-
 	td.Cmp(t, e.Error(), `no responder found for method "pipo", but one matches method "BINGO"`)
+	td.Cmp(t, e.Unwrap(), internal.NoResponderFound)
 
+	e = &internal.ErrorNoResponderFoundMistake{
+		Kind:      "matcher",
+		Orig:      "--not--used--",
+		Suggested: "BINGO",
+	}
+	td.Cmp(t, e.Error(), `no responder found despite BINGO`)
 	td.Cmp(t, e.Unwrap(), internal.NoResponderFound)
 }