Add unit test for archTag()

pkg/minikube/bootstrapper/images/images.go

@@ -122,7 +122,10 @@ func etcd(v semver.Version, mirror string) string {
 
 // archTag returns a CPU architecture suffix for images
 func archTag(needsArchSuffix bool) string {
-	if runtime.GOARCH == "amd64" || !needsArchSuffix {
+	return archTagInt(runtime.GOARCH, needsArchSuffix)
+}
+func archTagInt(arch string, needsArchSuffix bool) string {
+	if arch == "amd64" || !needsArchSuffix {
 		return ":"
 	}
 	return "-" + runtime.GOARCH + ":"

pkg/minikube/bootstrapper/images/images_test.go

@@ -17,6 +17,8 @@ limitations under the License.
 package images
 
 import (
+	"fmt"
+	"runtime"
 	"testing"
 
 	"github.com/google/go-cmp/cmp"
@@ -45,3 +47,30 @@ func TestAuxiliaryMirror(t *testing.T) {
 		t.Errorf("images mismatch (-want +got):\n%s", diff)
 	}
 }
+
+func TestArchTag(t *testing.T) {
+	tests := []struct {
+		arch     string
+		suffix   bool
+		expected string
+	}{
+		{
+			"amd64", true, ":",
+		},
+		{
+			"amd64", false, ":",
+		},
+		{
+			"arm64", false, ":",
+		},
+		{
+			"arm64", true, fmt.Sprintf("-%s:", runtime.GOARCH),
+		},
+	}
+	for _, test := range tests {
+		if tag := archTagInt(test.arch, test.suffix); tag != test.expected {
+			t.Errorf("For arch: %v and suffix flag: '%v' expected %v got %v",
+				test.arch, test.suffix, test.expected, tag)
+		}
+	}
+}