main.go

package main 

import (
  "net/http"

  "github.com/pressly/chi"
  "github.com/pressly/chi/render"
)

func a(w http.ResponseWriter, r *http.Request) {
  render.JSON(w, r, parse("a", r)) 
}

func b(w http.ResponseWriter, r *http.Request) {
  render.JSON(w, r, parse("b", r)) 
}

func c(w http.ResponseWriter, r *http.Request) {
  render.JSON(w, r, parse("c", r)) 
}

func parse(req string, r *http.Request) map[string]string {
  foo := chi.URLParam(r, "foo")
  bar := chi.URLParam(r, "bar")
  baz := chi.URLParam(r, "baz")

  return map[string]string{
    "foo": foo,
    "bar": bar,
    "baz": baz,
    "req": req,
  }
}

func router() http.Handler {
  r := chi.NewRouter()

  r.Route("/api/v1", func(r chi.Router) {
    r.Route("/files", func(r chi.Router) {
      r.Get("/:foo/hello/:bar", a)
      r.Get("/:bar/world/:baz", b)
      r.Get("/:bar/sups/:baz/:foo", c)
    })  
  })  

  return r
}

func main() {
  r := router()
  http.ListenAndServe(":3001", r)
}

main_test.go

package main

import (
	"encoding/json"
	"io/ioutil"
	"net/http"
	"net/http/httptest"
	"testing"
)

func req(t *testing.T, route string) map[string]string {
	s := httptest.NewServer(router())
	defer s.Close()
	r, _ := http.Get(s.URL + route)
	j := make(map[string]string)
	body, _ := ioutil.ReadAll(r.Body)
	t.Log(route)
	t.Logf("%s", body)
	json.Unmarshal(body, &j)
	return j
}

func TestRoutingBugA(t *testing.T) {
	t.Log("/api/v1/files/:foo/hello/:bar")
	r := req(t, "/api/v1/files/a/hello/b")

	if r["req"] != "a" {
		t.Error("incorrect route")
	}

	if r["foo"] != "a" {
		t.Error("foo should be a")
	}

	if r["bar"] != "b" {
		t.Error("bar should be b")
	}
}

func TestRoutingBugB(t *testing.T) {
	t.Log("/api/v1/files/:bar/world/:baz")
	r := req(t, "/api/v1/files/a/world/b")

	if r["req"] != "b" {
		t.Error("incorrect route")
	}

	if r["bar"] != "a" {
		t.Error("bar should be a, got:", r["bar"])
	}

	if r["baz"] != "b" {
		t.Error("baz should be b, got:", r["baz"])
	}
}

func TestRoutingBugC(t *testing.T) {
	t.Log("/api/v1/files/:bar/sups/:baz/:foo")
	r := req(t, "/api/v1/files/a/sups/b/c")

	if r["req"] != "c" {
		t.Error("incorrect route")
	}

	if r["bar"] != "a" {
		t.Error("bar should be a, got:", r["bar"])
	}

	if r["baz"] != "b" {
		t.Error("baz should be b, got:", r["baz"])
	}

	if r["foo"] != "c" {
		t.Error("foo should be c, got:", r["foo"])
	}
}

results

> go test -v .
=== RUN   TestRoutingBugA
--- PASS: TestRoutingBugA (0.00s)
	main_test.go:24: /api/v1/files/:foo/hello/:bar
	main_test.go:17: /api/v1/files/a/hello/b
	main_test.go:18: {"bar":"b","baz":"","foo":"a","req":"a"}
=== RUN   TestRoutingBugB
--- FAIL: TestRoutingBugB (0.00s)
	main_test.go:41: /api/v1/files/:bar/world/:baz
	main_test.go:17: /api/v1/files/a/world/b
	main_test.go:18: {"bar":"","baz":"b","foo":"a","req":"b"}
	main_test.go:49: bar should be a, got: 
=== RUN   TestRoutingBugC
--- FAIL: TestRoutingBugC (0.00s)
	main_test.go:58: /api/v1/files/:bar/sups/:baz/:foo
	main_test.go:17: /api/v1/files/a/sups/b/c
	main_test.go:18: {"bar":"","baz":"b","foo":"a","req":"c"}
	main_test.go:66: bar should be a, got: 
	main_test.go:74: foo should be c, got: a
FAIL
exit status 1
FAIL	github.com/zqzca/chibug	0.011s