diff --git a/buildfile_test.go b/buildfile_test.go
index e64b108660..c2ae79f199 100644
--- a/buildfile_test.go
+++ b/buildfile_test.go
@@ -4,12 +4,13 @@ import (
 	"io/ioutil"
 	"sync"
 	"testing"
+	"fmt"
 )
 
 // mkTestContext generates a build context from the contents of the provided dockerfile.
 // This context is suitable for use as an argument to BuildFile.Build()
 func mkTestContext(dockerfile string, files [][2]string, t *testing.T) Archive {
-	context, err := mkBuildContext(dockerfile, files)
+	context, err := mkBuildContext(fmt.Sprintf(dockerfile, unitTestImageId), files)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -29,7 +30,7 @@ type testContextTemplate struct {
 var testContexts []testContextTemplate = []testContextTemplate{
 	{
 		`
-from   docker-ut
+from   %s
 run    sh -c 'echo root:testpass > /tmp/passwd'
 run    mkdir -p /var/run/sshd
 run    [ "$(cat /tmp/passwd)" = "root:testpass" ]
@@ -40,7 +41,7 @@ run    [ "$(ls -d /var/run/sshd)" = "/var/run/sshd" ]
 
 	{
 		`
-from docker-ut
+from %s
 add foo /usr/lib/bla/bar
 run [ "$(cat /usr/lib/bla/bar)" = 'hello world!' ]
 `,
@@ -49,7 +50,7 @@ run [ "$(cat /usr/lib/bla/bar)" = 'hello world!' ]
 
 	{
 		`
-from docker-ut
+from %s
 add f /
 run [ "$(cat /f)" = "hello" ]
 add f /abc
@@ -75,7 +76,7 @@ run [ "$(cat /somewheeeere/over/the/rainbooow/ga)" = "bu" ]
 
 	{
 		`
-from docker-ut
+from %s
 env    FOO BAR
 run    [ "$FOO" = "BAR" ]
 `,