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// Package alice implements a middleware chaining solution.
package alice
import (
"net/http"
"net/http/httptest"
"reflect"
"testing"
"github.com/stretchr/testify/assert"
)
// A constructor for middleware
// that writes its own "tag" into the RW and does nothing else.
// Useful in checking if a chain is behaving in the right order.
func tagMiddleware(tag string) Constructor {
return func(h http.Handler) http.Handler {
return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w.Write([]byte(tag))
h.ServeHTTP(w, r)
})
}
}
// Not recommended (https://golang.org/pkg/reflect/#Value.Pointer),
// but the best we can do.
func funcsEqual(f1, f2 interface{}) bool {
val1 := reflect.ValueOf(f1)
val2 := reflect.ValueOf(f2)
return val1.Pointer() == val2.Pointer()
}
var testApp = http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
w.Write([]byte("app\n"))
})
// Tests creating a new chain
func TestNew(t *testing.T) {
c1 := func(h http.Handler) http.Handler {
return nil
}
c2 := func(h http.Handler) http.Handler {
return http.StripPrefix("potato", nil)
}
slice := []Constructor{c1, c2}
chain := New(slice...)
assert.True(t, funcsEqual(chain.constructors[0], slice[0]))
assert.True(t, funcsEqual(chain.constructors[1], slice[1]))
}
func TestThenWorksWithNoMiddleware(t *testing.T) {
assert.NotPanics(t, func() {
chain := New()
final := chain.Then(testApp)
assert.True(t, funcsEqual(final, testApp))
})
}
func TestThenTreatsNilAsDefaultServeMux(t *testing.T) {
chained := New().Then(nil)
assert.Equal(t, chained, http.DefaultServeMux)
}
func TestThenFuncTreatsNilAsDefaultServeMux(t *testing.T) {
chained := New().ThenFunc(nil)
assert.Equal(t, chained, http.DefaultServeMux)
}
func TestThenOrdersHandlersRight(t *testing.T) {
t1 := tagMiddleware("t1\n")
t2 := tagMiddleware("t2\n")
t3 := tagMiddleware("t3\n")
chained := New(t1, t2, t3).Then(testApp)
w := httptest.NewRecorder()
r, err := http.NewRequest("GET", "/", nil)
if err != nil {
t.Fatal(err)
}
chained.ServeHTTP(w, r)
assert.Equal(t, w.Body.String(), "t1\nt2\nt3\napp\n")
}
func TestAppendAddsHandlersCorrectly(t *testing.T) {
chain := New(tagMiddleware("t1\n"), tagMiddleware("t2\n"))
newChain := chain.Append(tagMiddleware("t3\n"), tagMiddleware("t4\n"))
assert.Equal(t, len(chain.constructors), 2)
assert.Equal(t, len(newChain.constructors), 4)
chained := newChain.Then(testApp)
w := httptest.NewRecorder()
r, err := http.NewRequest("GET", "/", nil)
if err != nil {
t.Fatal(err)
}
chained.ServeHTTP(w, r)
assert.Equal(t, w.Body.String(), "t1\nt2\nt3\nt4\napp\n")
}
func TestAppendRespectsImmutability(t *testing.T) {
chain := New(tagMiddleware(""))
newChain := chain.Append(tagMiddleware(""))
assert.NotEqual(t, &chain.constructors[0], &newChain.constructors[0])
}
func TestExtendAddsHandlersCorrectly(t *testing.T) {
chain1 := New(tagMiddleware("t1\n"), tagMiddleware("t2\n"))
chain2 := New(tagMiddleware("t3\n"), tagMiddleware("t4\n"))
newChain := chain1.Extend(chain2)
assert.Equal(t, len(chain1.constructors), 2)
assert.Equal(t, len(chain2.constructors), 2)
assert.Equal(t, len(newChain.constructors), 4)
chained := newChain.Then(testApp)
w := httptest.NewRecorder()
r, err := http.NewRequest("GET", "/", nil)
if err != nil {
t.Fatal(err)
}
chained.ServeHTTP(w, r)
assert.Equal(t, w.Body.String(), "t1\nt2\nt3\nt4\napp\n")
}
func TestExtendRespectsImmutability(t *testing.T) {
chain := New(tagMiddleware(""))
newChain := chain.Extend(New(tagMiddleware("")))
assert.NotEqual(t, &chain.constructors[0], &newChain.constructors[0])
}
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