diff --git a/provisioner/salt/provisioner.go b/provisioner/salt/provisioner.go
index 833200edf..9f641828c 100644
--- a/provisioner/salt/provisioner.go
+++ b/provisioner/salt/provisioner.go
@@ -18,6 +18,8 @@ import (
 
 var Ui packer.Ui
 
+const DefaultTempConfigDir = "/tmp/salt"
+
 type config struct {
 	// If true, run the salt-bootstrap script
 	SkipBootstrap bool   `mapstructure:"skip_bootstrap"`
@@ -72,7 +74,7 @@ func (p *Provisioner) Prepare(raws ...interface{}) error {
 	}
 
 	if p.config.TempConfigDir == "" {
-		p.config.TempConfigDir = "/tmp/salt"
+		p.config.TempConfigDir = DefaultTempConfigDir
 	}
 
 	if len(errs) > 0 {
diff --git a/provisioner/salt/provisioner_test.go b/provisioner/salt/provisioner_test.go
new file mode 100644
index 000000000..0e3242d1f
--- /dev/null
+++ b/provisioner/salt/provisioner_test.go
@@ -0,0 +1,46 @@
+package salt
+
+import (
+	"github.com/mitchellh/packer/packer"
+	"testing"
+)
+
+func testConfig() map[string]interface{} {
+	return map[string]interface{}{
+		"local_state_tree": "/Users/me/salt",
+	}
+}
+
+func TestProvisioner_Impl(t *testing.T) {
+	var raw interface{}
+	raw = &Provisioner{}
+	if _, ok := raw.(packer.Provisioner); !ok {
+		t.Fatalf("must be a Provisioner")
+	}
+}
+
+func TestProvisionerPrepare_Defaults(t *testing.T) {
+	var p Provisioner
+	config := testConfig()
+
+	err := p.Prepare(config)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	if p.config.TempConfigDir != DefaultTempConfigDir {
+		t.Errorf("unexpected temp config dir: %s", p.config.TempConfigDir)
+	}
+}
+
+func TestProvisionerPrepare_InvalidKey(t *testing.T) {
+	var p Provisioner
+	config := testConfig()
+
+	// Add a random key
+	config["i_should_not_be_valid"] = true
+	err := p.Prepare(config)
+	if err == nil {
+		t.Fatal("should have error")
+	}
+}