diff --git a/packer/artifact_mock.go b/packer/artifact_mock.go
index ec88007f3..a59af5331 100644
--- a/packer/artifact_mock.go
+++ b/packer/artifact_mock.go
@@ -2,16 +2,26 @@ package packer
 
 // MockArtifact is an implementation of Artifact that can be used for tests.
 type MockArtifact struct {
-	IdValue       string
-	DestroyCalled bool
+	BuilderIdValue string
+	FilesValue     []string
+	IdValue        string
+	DestroyCalled  bool
 }
 
-func (*MockArtifact) BuilderId() string {
-	return "bid"
+func (a *MockArtifact) BuilderId() string {
+	if a.BuilderIdValue == "" {
+		return "bid"
+	}
+
+	return a.BuilderIdValue
 }
 
-func (*MockArtifact) Files() []string {
-	return []string{"a", "b"}
+func (a *MockArtifact) Files() []string {
+	if a.FilesValue == nil {
+		return []string{"a", "b"}
+	}
+
+	return a.FilesValue
 }
 
 func (a *MockArtifact) Id() string {
diff --git a/post-processor/vagrant/post-processor_test.go b/post-processor/vagrant/post-processor_test.go
index 9046b0cf0..552c7ba02 100644
--- a/post-processor/vagrant/post-processor_test.go
+++ b/post-processor/vagrant/post-processor_test.go
@@ -1,7 +1,10 @@
 package vagrant
 
 import (
+	"bytes"
+	"compress/flate"
 	"github.com/mitchellh/packer/packer"
+	"strings"
 	"testing"
 )
 
@@ -9,11 +12,53 @@ func testConfig() map[string]interface{} {
 	return map[string]interface{}{}
 }
 
+func testPP(t *testing.T) *PostProcessor {
+	var p PostProcessor
+	if err := p.Configure(testConfig()); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	return &p
+}
+
+func testUi() *packer.BasicUi {
+	return &packer.BasicUi{
+		Reader: new(bytes.Buffer),
+		Writer: new(bytes.Buffer),
+	}
+}
+
 func TestPostProcessor_ImplementsPostProcessor(t *testing.T) {
 	var _ packer.PostProcessor = new(PostProcessor)
 }
 
-func TestBuilderPrepare_OutputPath(t *testing.T) {
+func TestPostProcessorPrepare_compressionLevel(t *testing.T) {
+	var p PostProcessor
+
+	// Default
+	c := testConfig()
+	delete(c, "compression_level")
+	if err := p.Configure(c); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	if p.config.CompressionLevel != flate.DefaultCompression {
+		t.Fatalf("bad: %#v", p.config.CompressionLevel)
+	}
+
+	// Set
+	c = testConfig()
+	c["compression_level"] = 7
+	if err := p.Configure(c); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	if p.config.CompressionLevel != 7 {
+		t.Fatalf("bad: %#v", p.config.CompressionLevel)
+	}
+}
+
+func TestPostProcessorPrepare_outputPath(t *testing.T) {
 	var p PostProcessor
 
 	// Default
@@ -32,6 +77,17 @@ func TestBuilderPrepare_OutputPath(t *testing.T) {
 	}
 }
 
+func TestPostProcessorPostProcess_badId(t *testing.T) {
+	artifact := &packer.MockArtifact{
+		BuilderIdValue: "invalid.packer",
+	}
+
+	_, _, err := testPP(t).PostProcess(testUi(), artifact)
+	if !strings.Contains(err.Error(), "artifact type") {
+		t.Fatalf("err: %s", err)
+	}
+}
+
 func TestProviderForName(t *testing.T) {
 	if v, ok := providerForName("virtualbox").(*VBoxProvider); !ok {
 		t.Fatalf("bad: %#v", v)