diff --git a/hank/HankAssert.hx b/hank/HankAssert.hx
index 7772fb3..df13a5e 100644
--- a/hank/HankAssert.hx
+++ b/hank/HankAssert.hx
@@ -41,5 +41,14 @@ class HankAssert {
         }
     }
 
-
+    public static function throws(f: Void -> Void, ?message: String) {
+        try {
+            f();
+            Assert.fail("Expected an exception to be thrown");
+        } catch (e: String) {
+            if (message != null) {
+                Assert.equals(message, e);
+            }
+        }
+    }
 }
\ No newline at end of file
diff --git a/tests/HInterfaceTest.hx b/tests/HInterfaceTest.hx
index a583a9c..38fb967 100644
--- a/tests/HInterfaceTest.hx
+++ b/tests/HInterfaceTest.hx
@@ -3,6 +3,7 @@ package tests;
 import utest.Test;
 import utest.Assert;
 
+import hank.HankAssert;
 using hank.Extensions;
 import hank.HInterface;
 import hank.StoryTree;
@@ -40,4 +41,14 @@ class HInterfaceTest extends utest.Test {
         assertExpr('test2', true);
     }
 
+    public function testNullErrors() {
+       HankAssert.throws(function() {
+           hInterface.evaluateExpr('undeclared_variable');
+       });
+    }
+
+    public function testIfIdiom() {
+       HankAssert.equals("", hInterface.evaluateExpr('if (false) "something"'));
+    }
+
 }
diff --git a/tests/StoryTest.hx b/tests/StoryTest.hx
index 78d7b4b..7e82108 100644
--- a/tests/StoryTest.hx
+++ b/tests/StoryTest.hx
@@ -11,12 +11,12 @@ class StoryTest extends hank.StoryTestCase {
 
             for (file in files) {
                 if (StringTools.endsWith(file, '.hlog')) {
-                    trace('    Running ${file}');
 
                     var disabled = file.indexOf("disabled") != -1;
                     var debug = file.indexOf("debug") != -1;
                     var partial = file.indexOf("partial") != -1;
                     if (!disabled) {
+                        trace('    Running ${file}');
                         validateAgainstTranscript('examples/${folder}/main.hank', 'examples/${folder}/${file}', !partial);
                     }
                 }