diff --git a/cli.go b/cli.go
index 8d11614..acccb07 100644
--- a/cli.go
+++ b/cli.go
@@ -8,8 +8,30 @@ import (
 	"sync"
 )
 
+// NewApp builds the proxycheck CLI application. It is shared by the cmd binary
+// and the tests so both exercise the same flag wiring.
+func NewApp() *cli.App {
+	return &cli.App{
+		Name:        "proxycheck",
+		Description: "Proxy checker tool",
+		Version:     "0.0.5",
+		Flags: []cli.Flag{
+			&cli.StringFlag{Name: "judge", Usage: "Set judge", Value: "proxyjudge.us"},
+			&cli.IntFlag{Name: "threads", Usage: "Count of threads", Value: 10},
+		},
+		Action: Action,
+	}
+}
+
 func Action(c *cli.Context) error {
 
+	// Resolve the judge from the --judge flag before doing any work; an unknown
+	// name aborts here, so no proxy is checked.
+	judge, err := ResolveJudge(c.String("judge"))
+	if err != nil {
+		return err
+	}
+
 	// If pass args, use it or read stdin as input file with proxies
 	var feed Feed
 
@@ -28,7 +50,7 @@ func Action(c *cli.Context) error {
 		go func(proxyAddrs chan string) {
 			defer wg.Done()
 			for proxyAddr := range proxyAddrs {
-				if res := Check(proxyAddr, &AZEnvPhpJudge{}); res.Online {
+				if res := Check(proxyAddr, judge); res.Online {
 					fmt.Printf("%s\t%s\t%s\n", proxyAddr, strings.Join(res.Protocols, ","), res.Speed.String())
 				} else {
 					fmt.Fprintf(os.Stderr, "invalid proxy %s: %v\n", proxyAddr, res.Err)
@@ -47,6 +69,10 @@ func Action(c *cli.Context) error {
 		proxyAddrs <- proxyAddr
 	}
 
+	// Closing the channel lets the workers' range loops finish so wg.Wait
+	// returns once the feed is exhausted.
+	close(proxyAddrs)
+
 	wg.Wait()
 	return nil
 }
diff --git a/cli_test.go b/cli_test.go
new file mode 100644
index 0000000..b08391e
--- /dev/null
+++ b/cli_test.go
@@ -0,0 +1,18 @@
+package proxycheck
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+// TestApp_UnknownJudge is the regression test for the --judge flag: an unknown
+// judge name must abort with an error before any proxy is checked. A deliberately
+// unparsable address keeps the run off the network if the guard is missing.
+func TestApp_UnknownJudge(t *testing.T) {
+	err := NewApp().Run([]string{"proxycheck", "--judge", "foo", "not-an-addr"})
+	assert.Error(t, err, "unknown judge must cause a non-nil error")
+	if err != nil {
+		assert.Contains(t, err.Error(), "unknown judge: foo")
+	}
+}
diff --git a/cmd/main.go b/cmd/main.go
index bdc6ef7..d1a3b33 100644
--- a/cmd/main.go
+++ b/cmd/main.go
@@ -5,20 +5,10 @@ import (
 	"os"
 
 	"github.com/memclutter/proxycheck"
-	cli "github.com/urfave/cli/v2"
 )
 
 func main() {
-	if err := (&cli.App{
-		Name:        "proxycheck",
-		Description: "Proxy checker tool",
-		Version:     "0.0.5",
-		Flags: []cli.Flag{
-			&cli.StringFlag{Name: "judge", Usage: "Set judge", Value: "proxyjudge.us"},
-			&cli.IntFlag{Name: "threads", Usage: "Count of threads", Value: 10},
-		},
-		Action: proxycheck.Action,
-	}).Run(os.Args); err != nil {
+	if err := proxycheck.NewApp().Run(os.Args); err != nil {
 		log.Fatalf("app run failed: %s", err)
 	}
 }
diff --git a/judges.go b/judges.go
index e02fc34..cad0904 100644
--- a/judges.go
+++ b/judges.go
@@ -1,6 +1,11 @@
 package proxycheck
 
-import "time"
+import (
+	"fmt"
+	"sort"
+	"strings"
+	"time"
+)
 
 type AZEnvPhpJudge struct{}
 
@@ -16,3 +21,24 @@ var Judges = map[string]Judge{
 	"azenv.php":     AZEnvPhpJudge{},
 	"proxyjudge.us": ProxyjudgeUsJudge{},
 }
+
+// ResolveJudge returns the Judge registered under name. An unknown name yields
+// an error that lists the available judge names.
+func ResolveJudge(name string) (Judge, error) {
+	judge, ok := Judges[name]
+	if !ok {
+		return nil, fmt.Errorf("unknown judge: %s (available: %s)", name, judgeNames())
+	}
+	return judge, nil
+}
+
+// judgeNames returns the registered judge names, sorted and comma-joined, so
+// error messages are deterministic.
+func judgeNames() string {
+	names := make([]string, 0, len(Judges))
+	for name := range Judges {
+		names = append(names, name)
+	}
+	sort.Strings(names)
+	return strings.Join(names, ", ")
+}
diff --git a/judges_test.go b/judges_test.go
index 2e50129..0ea11ba 100644
--- a/judges_test.go
+++ b/judges_test.go
@@ -1,11 +1,37 @@
 package proxycheck
 
 import (
-	"github.com/stretchr/testify/assert"
 	"net/url"
 	"testing"
+
+	"github.com/stretchr/testify/assert"
 )
 
+func TestResolveJudge(t *testing.T) {
+	t.Run("azenv.php resolves", func(t *testing.T) {
+		judge, err := ResolveJudge("azenv.php")
+		assert.NoError(t, err)
+		assert.IsType(t, AZEnvPhpJudge{}, judge)
+	})
+
+	t.Run("proxyjudge.us resolves", func(t *testing.T) {
+		judge, err := ResolveJudge("proxyjudge.us")
+		assert.NoError(t, err)
+		assert.IsType(t, ProxyjudgeUsJudge{}, judge)
+	})
+
+	t.Run("unknown name errors", func(t *testing.T) {
+		judge, err := ResolveJudge("foo")
+		assert.Nil(t, judge)
+		assert.Error(t, err)
+		if err != nil {
+			assert.Contains(t, err.Error(), "unknown judge: foo")
+			assert.Contains(t, err.Error(), "azenv.php")
+			assert.Contains(t, err.Error(), "proxyjudge.us")
+		}
+	})
+}
+
 func TestJudge_TargetURL(t *testing.T) {
 	testingTable := []struct {
 		title string