diff --git a/python_terraform/__init__.py b/python_terraform/__init__.py
index 8de4c0b..6ed9362 100644
--- a/python_terraform/__init__.py
+++ b/python_terraform/__init__.py
@@ -108,9 +108,23 @@ class Terraform(object):
         """
         default = kwargs
         default['force'] = force
-        option_dict = self._generate_default_options(default)
+        options = self._generate_default_options(default)
         args = self._generate_default_args(dir_or_plan)
-        return self.cmd('destroy', *args, **option_dict)
+        return self.cmd('destroy', *args, **options)
+
+    def plan(self, dir_or_plan=None, detailed_exitcode=IsFlagged, **kwargs):
+        """
+        refert to https://www.terraform.io/docs/commands/plan.html
+        :param detailed_exitcode: Return a detailed exit code when the command exits.
+        :param dir_or_plan: relative path to plan/folder
+        :param kwargs: options
+        :return: ret_code, stdout, stderr
+        """
+        options = kwargs
+        options['detailed_exitcode'] = detailed_exitcode
+        options = self._generate_default_options(options)
+        args = self._generate_default_args(dir_or_plan)
+        return self.cmd('plan', *args, **options)
 
     def generate_cmd_string(self, cmd, *args, **kwargs):
         """
diff --git a/test/test_terraform.py b/test/test_terraform.py
index f55323c..eacb781 100644
--- a/test/test_terraform.py
+++ b/test/test_terraform.py
@@ -32,7 +32,8 @@ CMD_CASES = [
     ]
 ]
 
-@pytest.fixture()
+
+@pytest.fixture(scope='function')
 def fmt_test_file(request):
     target = os.path.join(current_path, 'bad_fmt', 'test.backup')
     orgin = os.path.join(current_path, 'bad_fmt', 'test.tf')
@@ -131,6 +132,8 @@ class TestTerraform(object):
                                  no_color=IsNotFlagged)
         out = out.replace('\n', '')
         assert '\x1b[0m\x1b[1m\x1b[32mApply' in out
+        out = tf.output('test_output')
+        assert 'test2' in out
 
     def test_get_output(self):
         tf = Terraform(working_dir=current_path, variables={'test_var': 'test'})
@@ -143,7 +146,18 @@ class TestTerraform(object):
         assert ret == 0
         assert 'Destroy complete! Resources: 0 destroyed.' in out
 
-    def test_fmt(self):
+    @pytest.mark.parametrize(
+        ("plan", "variables", "expected_ret"),
+        [
+            ('vars_require_input', {}, 1)
+        ]
+    )
+    def test_plan(self, plan, variables, expected_ret):
+        tf = Terraform(working_dir=current_path, variables=variables)
+        ret, out, err = tf.plan(plan)
+        assert ret == expected_ret
+
+    def test_fmt(self, fmt_test_file):
         tf = Terraform(working_dir=current_path, variables={'test_var': 'test'})
         ret, out, err = tf.fmt(diff=True)
         assert ret == 0
diff --git a/test/vars_require_input/main.tf b/test/vars_require_input/main.tf
new file mode 100644
index 0000000..43e8e65
--- /dev/null
+++ b/test/vars_require_input/main.tf
@@ -0,0 +1,20 @@
+variable "ami" {
+  default = "foo"
+  type    = "string"
+}
+
+variable "list" {
+  default = []
+  type    = "list"
+}
+
+variable "map" {
+  default = {}
+  type = "map"
+}
+
+resource "aws_instance" "bar" {
+  foo = "${var.ami}"
+  bar = "${join(",", var.list)}"
+  baz = "${join(",", keys(var.map))}"
+}
\ No newline at end of file