diff --git a/hack/update-generated-api-compatibility-data.sh b/hack/update-generated-api-compatibility-data.sh
index 94f5a7200b7..415a09d889e 100755
--- a/hack/update-generated-api-compatibility-data.sh
+++ b/hack/update-generated-api-compatibility-data.sh
@@ -23,11 +23,14 @@ source "${KUBE_ROOT}/hack/lib/init.sh"
 
 kube::golang::setup_env
 
+# run in module mode to match test command in readme.md
+export GO111MODULE=on
+
 # UPDATE_COMPATIBILITY_FIXTURE_DATA=true regenerates fixture data if needed.
 # -run //HEAD only runs the test cases comparing against testdata for HEAD.
 # We suppress the output because we are expecting to have changes.
 # We suppress the test failure that occurs when there are changes.
-UPDATE_COMPATIBILITY_FIXTURE_DATA=true go test ./vendor/k8s.io/api -run //HEAD >/dev/null 2>&1 || true
+UPDATE_COMPATIBILITY_FIXTURE_DATA=true go test k8s.io/api -run //HEAD >/dev/null 2>&1 || true
 
 # Now that we have regenerated data at HEAD, run the test without suppressing output or failures
-go test ./vendor/k8s.io/api -run //HEAD -count=1
+go test k8s.io/api -run //HEAD -count=1
diff --git a/staging/src/k8s.io/api/testdata/README.md b/staging/src/k8s.io/api/testdata/README.md
index 425b30be226..f6c9277215e 100644
--- a/staging/src/k8s.io/api/testdata/README.md
+++ b/staging/src/k8s.io/api/testdata/README.md
@@ -29,7 +29,7 @@ HEAD/
 To run serialization tests just for the current version:
 
 ```sh
-go test ./vendor/k8s.io/api -run //HEAD
+go test k8s.io/api -run //HEAD
 ```
 
 All three formats of a given group/version/kind are expected to decode successfully to identical objects,
@@ -37,7 +37,7 @@ and to round-trip back to serialized form with identical bytes.
 Adding new fields or API types *is* expected to modify these fixtures. To regenerate them, run:
 
 ```sh
-UPDATE_COMPATIBILITY_FIXTURE_DATA=true go test ./vendor/k8s.io/api -run //HEAD
+UPDATE_COMPATIBILITY_FIXTURE_DATA=true go test k8s.io/api -run //HEAD
 ```
 
 ## Previous versions
@@ -57,12 +57,12 @@ This requires making optional scalar and struct fields pointers so that protobuf
 To run serialization tests just for a previous version, like `v1.14.0`:
 
 ```sh
-go test ./vendor/k8s.io/api -run //v1.14.0
+go test k8s.io/api -run //v1.14.0
 ```
 
 To run serialization tests for a particular group/version/kind, like `apps/v1` `Deployment`:
 ```sh
-go test ./vendor/k8s.io/api -run /apps.v1.Deployment/
+go test k8s.io/api -run /apps.v1.Deployment/
 ```
 
 Failures to decode, to round-trip identical bytes, or to decode identical objects from json/yaml/protobuf,