Prepare tests for impending knative/pkg version bump

knative/pkg#2548 changes pkg/changeset.Get to
read VCS information from information embedded by the Go compiler into
built binaries, instead of relying on the convention that a kodata/HEAD
symlink exists pointing to the repo's .git/HEAD, and a kodata/refs
points to .git/refs.

This fails in tests though, since tests don't stamp this information
into the binary where it can be read.

This change removes our tests' usage of changeset.Get and instead
replaces those fake commit SHAs with more obviously placeholder values.
It doesn't seem that the tests cared that it was an actual SHA, let
along the actual current SHA, they just needed any value that looked
like a SHA.

pkg/pod/pod_test.go

@@ -41,7 +41,6 @@ import (
 	"k8s.io/apimachinery/pkg/api/resource"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	fakek8s "k8s.io/client-go/kubernetes/fake"
-	"knative.dev/pkg/changeset"
 	logtesting "knative.dev/pkg/logging/testing"
 	"knative.dev/pkg/system"
 
@@ -63,22 +62,17 @@ var (
 
 	defaultActiveDeadlineSeconds = int64(config.DefaultTimeoutMinutes * 60 * deadlineFactor)
 
-	fakeVersion string
-
 	resourceQuantityCmp = cmp.Comparer(func(x, y resource.Quantity) bool {
 		return x.Cmp(y) == 0
 	})
 	volumeSort      = cmpopts.SortSlices(func(i, j corev1.Volume) bool { return i.Name < j.Name })
 	volumeMountSort = cmpopts.SortSlices(func(i, j corev1.VolumeMount) bool { return i.Name < j.Name })
 )
 
+const fakeVersion = "0000000000000000000000000000000000000000"
+
 func init() {
 	os.Setenv("KO_DATA_PATH", "./testdata/")
-	commit, err := changeset.Get()
-	if err != nil {
-		panic(err)
-	}
-	fakeVersion = commit
 }
 
 func TestPodBuild(t *testing.T) {

pkg/reconciler/taskrun/taskrun_test.go

@@ -61,7 +61,6 @@ import (
 	ktesting "k8s.io/client-go/testing"
 	"k8s.io/client-go/tools/record"
 	"knative.dev/pkg/apis"
-	"knative.dev/pkg/changeset"
 	cminformer "knative.dev/pkg/configmap/informer"
 	"knative.dev/pkg/controller"
 	"knative.dev/pkg/kmeta"
@@ -398,12 +397,13 @@ var (
 		},
 	}
 
-	fakeVersion                string
 	gitResourceSecurityContext = &corev1.SecurityContext{
 		RunAsUser: ptr.Int64(0),
 	}
 )
 
+const fakeVersion string = "0000000000000000000000000000000000000000"
+
 func placeToolsInitContainer(steps []string) corev1.Container {
 	return corev1.Container{
 		Command: append([]string{"/ko-app/entrypoint", "init", "/ko-app/entrypoint", entrypointLocation}, steps...),
@@ -442,11 +442,6 @@ func createServiceAccount(t *testing.T, assets test.Assets, name string, namespa
 
 func init() {
 	os.Setenv("KO_DATA_PATH", "./testdata/")
-	commit, err := changeset.Get()
-	if err != nil {
-		panic(err)
-	}
-	fakeVersion = commit
 }
 
 func getRunName(tr *v1beta1.TaskRun) string {