Add tests for dupe flags and commands and other confusing things

main.go

@@ -20,7 +20,7 @@ type appModifier func(app *cli.App)
 
 var appModifiers []appModifier
 
-func cliMain(args ...string) error {
+func buildApp() *cli.App {
 	app := cli.NewApp()
 
 	app.Usage = "A fast regex parser, extractor and realtime aggregator"
@@ -116,7 +116,11 @@ func cliMain(args ...string) error {
 		modifier(app)
 	}
 
-	return app.Run(args)
+	return app
+}
+
+func cliMain(args ...string) error {
+	return buildApp().Run(args)
 }
 
 func main() {

main_test.go

@@ -12,3 +12,38 @@ func TestMain(t *testing.T) {
 	assert.Error(t, cliMain("main"))
 	assert.NoError(t, cliMain("main", "--help"))
 }
+
+func TestDupeCommands(t *testing.T) {
+	commands := make(map[string]struct{})
+	app := buildApp()
+
+	for _, cmd := range app.Commands {
+		for _, name := range cmd.Names() {
+			assert.NotContains(t, commands, name)
+			commands[name] = struct{}{}
+		}
+	}
+}
+
+func TestDupeFlags(t *testing.T) {
+	app := buildApp()
+	for _, cmd := range app.Commands {
+		flags := make(map[string]struct{})
+
+		// Global (even though technically can dupe, it's confusing, so prevent)
+		for _, flag := range app.Flags {
+			for _, name := range flag.Names() {
+				assert.NotContains(t, flags, name)
+				flags[name] = struct{}{}
+			}
+		}
+
+		// And the specific flags
+		for _, flag := range cmd.Flags {
+			for _, name := range flag.Names() {
+				assert.NotContains(t, flags, name)
+				flags[name] = struct{}{}
+			}
+		}
+	}
+}