diff --git a/internal/driver/ioscompanion/device_test.go b/internal/driver/ioscompanion/device_test.go
index 6865181..5cacfc0 100644
--- a/internal/driver/ioscompanion/device_test.go
+++ b/internal/driver/ioscompanion/device_test.go
@@ -195,15 +195,3 @@ func TestDeviceCloseStopsRunnerAndTunnel(t *testing.T) {
 		t.Fatal("Close must close the usbmux tunnel")
 	}
 }
-
-func equalArgs(got, want []string) bool {
-	if len(got) != len(want) {
-		return false
-	}
-	for i := range got {
-		if got[i] != want[i] {
-			return false
-		}
-	}
-	return true
-}
diff --git a/internal/driver/ioscompanion/devicerunner.go b/internal/driver/ioscompanion/devicerunner.go
index cfea3d6..a26fc5b 100644
--- a/internal/driver/ioscompanion/devicerunner.go
+++ b/internal/driver/ioscompanion/devicerunner.go
@@ -176,7 +176,7 @@ func (d *Driver) buildDeviceRunnerIfNeeded(ctx context.Context, companionDir, de
 		return nil
 	}
 
-	if out, genErr := runQuiet(ctx, companionDir, xcodegenArgs(filepath.Join(companionDir, "project.yml"))...); genErr != nil {
+	if out, genErr := runQuiet(ctx, companionDir, "xcodegen", "--spec", filepath.Join(companionDir, "project.yml")); genErr != nil {
 		return fmt.Errorf("xcodegen: %w: %s", genErr, strings.TrimSpace(string(out)))
 	}
 
@@ -204,11 +204,6 @@ func buildCacheKey(companionDir string, creds signingCredentials) (string, error
 	return hex.EncodeToString(sum[:]), nil
 }
 
-// xcodegenArgs regenerates the runner project from its spec.
-func xcodegenArgs(specPath string) []string {
-	return []string{"xcodegen", "--spec", specPath}
-}
-
 // buildForTestingArgs builds the runner for a generic device destination, signed
 // through the App Store Connect API key with automatic provisioning. A generic
 // destination keeps the build off any specific booted device; the wildcard dev
diff --git a/internal/driver/ioscompanion/devicerunner_test.go b/internal/driver/ioscompanion/devicerunner_test.go
index 3777929..f0e3486 100644
--- a/internal/driver/ioscompanion/devicerunner_test.go
+++ b/internal/driver/ioscompanion/devicerunner_test.go
@@ -7,59 +7,6 @@ import (
 	"testing"
 )
 
-func TestBuildForTestingArgs(t *testing.T) {
-	creds := signingCredentials{team: "TEAM1", authKeyPath: "/k/AuthKey.p8", authKeyID: "KID", authIssuerID: "ISS"}
-	args := buildForTestingArgs("/p/CompanionRunner.xcodeproj", "/d/derived", creds)
-	joined := strings.Join(args, " ")
-	for _, want := range []string{
-		"xcodebuild build-for-testing",
-		"-project /p/CompanionRunner.xcodeproj",
-		"-scheme CompanionRunner",
-		"-destination generic/platform=iOS",
-		"-derivedDataPath /d/derived",
-		"-allowProvisioningUpdates",
-		"-authenticationKeyPath /k/AuthKey.p8",
-		"-authenticationKeyID KID",
-		"-authenticationKeyIssuerID ISS",
-		"CODE_SIGNING_ALLOWED=YES",
-		"CODE_SIGNING_REQUIRED=YES",
-		"CODE_SIGN_STYLE=Automatic",
-		"DEVELOPMENT_TEAM=TEAM1",
-		"GENERATE_INFOPLIST_FILE=YES",
-	} {
-		if !strings.Contains(joined, want) {
-			t.Errorf("build args missing %q in %q", want, joined)
-		}
-	}
-}
-
-func TestTestWithoutBuildingArgs(t *testing.T) {
-	creds := signingCredentials{team: "TEAM1", authKeyPath: "/k/AuthKey.p8", authKeyID: "KID", authIssuerID: "ISS"}
-	args := testWithoutBuildingArgs("/x/run.xctestrun", "00008140-HW", creds)
-	joined := strings.Join(args, " ")
-	for _, want := range []string{
-		"xcodebuild test-without-building",
-		"-xctestrun /x/run.xctestrun",
-		"-destination platform=iOS,id=00008140-HW",
-		"-allowProvisioningUpdates",
-		"-authenticationKeyPath /k/AuthKey.p8",
-		"-authenticationKeyID KID",
-		"-authenticationKeyIssuerID ISS",
-	} {
-		if !strings.Contains(joined, want) {
-			t.Errorf("test args missing %q in %q", want, joined)
-		}
-	}
-}
-
-func TestXcodegenArgs(t *testing.T) {
-	args := xcodegenArgs("/c/project.yml")
-	want := []string{"xcodegen", "--spec", "/c/project.yml"}
-	if !equalArgs(args, want) {
-		t.Fatalf("xcodegen args = %v, want %v", args, want)
-	}
-}
-
 func TestTestTargetNameFromJSON(t *testing.T) {
 	// A device xctestrun-as-json: one test-target dict plus the metadata entry.
 	data := []byte(`{