letsencrypt: Tests for handler that proxies challenge requests

Doesn't test the SkipInsecureVerify proxy setting, but that can be done at another time.

caddy/letsencrypt/handler_test.go

+package letsencrypt
+
+import (
+	"net"
+	"net/http"
+	"net/http/httptest"
+	"testing"
+)
+
+func TestRequestCallbackNoOp(t *testing.T) {
+	// try base paths that aren't handled by this handler
+	for _, url := range []string{
+		"http://localhost/",
+		"http://localhost/foo.html",
+		"http://localhost/.git",
+		"http://localhost/.well-known/",
+		"http://localhost/.well-known/acme-challenging",
+	} {
+		req, err := http.NewRequest("GET", url, nil)
+		if err != nil {
+			t.Fatalf("Could not craft request, got error: %v", err)
+		}
+		rw := httptest.NewRecorder()
+		if RequestCallback(rw, req) {
+			t.Errorf("Got true with this URL, but shouldn't have: %s", url)
+		}
+	}
+}
+
+func TestRequestCallbackSuccess(t *testing.T) {
+	expectedPath := challengeBasePath + "/asdf"
+
+	// Set up fake acme handler backend to make sure proxying succeeds
+	var proxySuccess bool
+	ts := httptest.NewUnstartedServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		proxySuccess = true
+		if r.URL.Path != expectedPath {
+			t.Errorf("Expected path '%s' but got '%s' instead", expectedPath, r.URL.Path)
+		}
+	}))
+
+	// Custom listener that uses the port we expect
+	ln, err := net.Listen("tcp", "127.0.0.1:"+AlternatePort)
+	if err != nil {
+		t.Fatalf("Unable to start test server listener: %v", err)
+	}
+	ts.Listener = ln
+
+	// Start our engines and run the test
+	ts.Start()
+	defer ts.Close()
+	req, err := http.NewRequest("GET", "http://127.0.0.1:"+AlternatePort+expectedPath, nil)
+	if err != nil {
+		t.Fatalf("Could not craft request, got error: %v", err)
+	}
+	rw := httptest.NewRecorder()
+
+	RequestCallback(rw, req)
+
+	if !proxySuccess {
+		t.Fatal("Expected request to be proxied, but it wasn't")
+	}
+}