Add tests for ansible-local provisioner

provisioner/ansible-local/provisioner_test.go

+package ansiblelocal
+
+import (
+	"github.com/mitchellh/packer/packer"
+	"io/ioutil"
+	"os"
+	"testing"
+)
+
+func testConfig() map[string]interface{} {
+	m := make(map[string]interface{})
+	return m
+}
+
+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_PlaybookFile(t *testing.T) {
+	var p Provisioner
+	config := testConfig()
+
+	err := p.Prepare(config)
+	if err == nil {
+		t.Fatal("should have error")
+	}
+
+	config["playbook_file"] = ""
+	err = p.Prepare(config)
+	if err == nil {
+		t.Fatal("should have error")
+	}
+
+	playbook_file, err := ioutil.TempFile("", "playbook")
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+	defer os.Remove(playbook_file.Name())
+
+	config["playbook_file"] = playbook_file.Name()
+	err = p.Prepare(config)
+	if err != nil {
+		t.Fatalf("err: %s", err)
+	}
+}