diff --git a/test/unit/codegen_test.go b/test/unit/codegen_test.go
index c3364a51..46f112c6 100644
--- a/test/unit/codegen_test.go
+++ b/test/unit/codegen_test.go
@@ -1,10 +1,27 @@
 package unit_test
 
-import "testing"
+import (
+	"os"
+	"strings"
+	"testing"
+
+	"knative.dev/hack/pkg/utest/require"
+)
 
 func TestCodegen(t *testing.T) {
 	t.Parallel()
+	tmpdir := t.TempDir()
+	execPermission := os.FileMode(0o755)
+	require.NoError(t, os.MkdirAll(tmpdir+"/go/bin", execPermission))
+	require.NoError(t, os.WriteFile(
+		tmpdir+"/go/bin/deepcopy-gen",
+		[]byte(strings.Join([]string{"#!/bin/bash",
+			`git restore test/e2e/apis/hack/v1alpha1/zz_generated.deepcopy.go`,
+			`echo "Deepcopy generation complete"`,
+			"exit 248"}, "\n")),
+		execPermission))
 	sc := newShellScript(
+		envs(map[string]string{"TMPDIR": tmpdir}),
 		loadFile("source-codegen-library.bash"),
 		mockGo(),
 	)
@@ -13,6 +30,26 @@ func TestCodegen(t *testing.T) {
 			"knative.dev/hack/test/e2e/apis/hack/v1alpha1/generated " +
 			"knative.dev/hack/test/e2e/apis " +
 			"hack:v1alpha1",
+		retcode: retcode(248),
+		stdout: equal(`WARNING: generate-groups.sh is deprecated.
+WARNING: Please use k8s.io/code-generator/kube_codegen.sh instead.
+
+WARNING: generate-internal-groups.sh is deprecated.
+WARNING: Please use k8s.io/code-generator/kube_codegen.sh instead.
+
+go install k8s.io/code-generator/cmd/applyconfiguration-gen k8s.io/code-generator/cmd/client-gen k8s.io/code-generator/cmd/conversion-gen k8s.io/code-generator/cmd/deepcopy-gen k8s.io/code-generator/cmd/defaulter-gen k8s.io/code-generator/cmd/informer-gen k8s.io/code-generator/cmd/lister-gen k8s.io/code-generator/cmd/openapi-gen
+Generating deepcopy funcs
+Deepcopy generation complete
+`,
+		),
+		stderr: equal(strings.TrimLeft(`
+╭───────────────────────────────────────────────────────────╮
+│                                                           │
+│   WARN: Failed to determine the knative.dev/pkg package   │
+│                                                           │
+╰───────────────────────────────────────────────────────────╯
+--- Cleaning up generated code
+`, "\n")),
 	}}
 	for i := range tcs {
 		tc := tcs[i]
diff --git a/test/unit/scripts/source-codegen-library.bash b/test/unit/scripts/source-codegen-library.bash
index 352e8131..95e46296 100755
--- a/test/unit/scripts/source-codegen-library.bash
+++ b/test/unit/scripts/source-codegen-library.bash
@@ -16,7 +16,5 @@
 
 set -Eeuo pipefail
 
-pushd "$(dirname "${BASH_SOURCE[0]:-$0}")/../.." > /dev/null
 # shellcheck disable=SC1090
-source "$(go run ./cmd/script codegen-library.sh)"
-popd > /dev/null
+source "$(go run "$(realpath "$(dirname "$0")/../../cmd/script")" codegen-library.sh)"