Add tests for ValidateStage

src/TerraformValidateStage.groovy

@@ -20,7 +20,7 @@ class TerraformValidateStage implements Stage, DecoratableStage {
         Jenkinsfile.build(pipelineConfiguration())
     }
 
-    private Closure pipelineConfiguration() {
+    public Closure pipelineConfiguration() {
         applyPlugins()
 
         def validateCommand = TerraformValidateCommand.instance()

test/DummyJenkinsfile.groovy

@@ -1,7 +1,7 @@
 class DummyJenkinsfile {
     public docker
     public scm
-    public env
+    public env = [:]
 
     public DummyJenkinsfile() {
         docker = this

test/TerraformPluginVersion12Test.groovy

@@ -2,6 +2,7 @@ import static org.hamcrest.Matchers.containsString
 import static org.hamcrest.Matchers.endsWith
 import static org.hamcrest.Matchers.not
 import static org.junit.Assert.assertThat
+import static org.junit.Assert.assertTrue
 import static org.mockito.Matchers.any
 import static org.mockito.Matchers.eq
 import static org.mockito.Mockito.spy
@@ -21,6 +22,21 @@ class TerraformPluginVersion12Test {
         TerraformFormatCommand.reset()
     }
 
+    class AddInitBefore {
+        @Test
+        void runsTheInnerClosure() {
+            def plugin = new TerraformPluginVersion12()
+            def wasRun = false
+            def innerClosure = { wasRun = true }
+
+            def beforeClosure = plugin.addInitBefore()
+            beforeClosure.delegate = new DummyJenkinsfile()
+            beforeClosure(innerClosure)
+
+            assertTrue(wasRun)
+        }
+    }
+
     class InitCommandForValidate {
         @Test
         void createsCommandWithNoBackend() {

test/TerraformValidateStageTest.groovy

@@ -0,0 +1,39 @@
+import static org.mockito.Mockito.spy
+import static org.hamcrest.Matchers.isA
+import static org.junit.Assert.assertThat
+
+import org.junit.After
+import org.junit.Test
+import org.junit.runner.RunWith
+import de.bechte.junit.runners.context.HierarchicalContextRunner
+
+@RunWith(HierarchicalContextRunner.class)
+class TerraformValidateStageTest {
+    @After
+    void resetPlugins() {
+        TerraformValidateStage.resetPlugins()
+    }
+
+    public class PipelineConfiguration {
+        @Test
+        void returnsAJobDslClosure() {
+            def validateStage = new TerraformValidateStage()
+
+            def result = validateStage.pipelineConfiguration()
+
+            assertThat(result, isA(Closure.class))
+        }
+
+        // This should be split into separate tests, and assert behavior
+        @Test
+        void justExerciseClosureNoAssertions() {
+            Jenkinsfile.instance = spy(new Jenkinsfile())
+            Jenkinsfile.original = new DummyJenkinsfile()
+            def validateStage = new TerraformValidateStage()
+
+            def closure = validateStage.pipelineConfiguration()
+            closure.delegate = Jenkinsfile.original
+            closure()
+        }
+    }
+}