From 5178719ac99d9f777e10cc0f95522113e2782902 Mon Sep 17 00:00:00 2001
From: Caleb Spare <cespare@gmail.com>
Date: Wed, 28 Mar 2012 21:32:50 -0700
Subject: [PATCH] Add assert.throwsException.

---
 shoulda.js | 22 +++++++++++++++++++++-
 1 file changed, 21 insertions(+), 1 deletion(-)

diff --git a/shoulda.js b/shoulda.js
index 7f76e96..f5ae42d 100644
--- a/shoulda.js
+++ b/shoulda.js
@@ -61,6 +61,26 @@ var assert = {
       this.fail("Expected " + this._printObject(expected) + " but received " + this._printObject(actual));
   },
 
+  // It would be nice to call this 'throws', but all Java keywords are Javascript keywords and hence 'throws'
+  // is a JS keyword. Sigh.
+  throwsException: function(expression, expectedExceptionName) {
+    try {
+      expression();
+    } catch(exception) {
+      if (expectedExceptionName) {
+        if (exception.name === expectedExceptionName) return;
+        else {
+          assert.fail("Expected exception " + expectedExceptionName + " to be thrown but exception " +
+            exception.name + " was thrown instead.");
+        }
+      } else return;
+    }
+    if (expectedExceptionName)
+      assert.fail("Expected exception " + expectedExceptionName + " but no exception was thrown.");
+    else
+      assert.fail("Expected exception but none was thrown.");
+  },
+
   fail: function(message) { throw new AssertionError(message); },
 
   /* Used for printing the arguments passed to assertions. */
@@ -294,4 +314,4 @@ Stubs = {
       stubProperties.object[stubProperties.propertyName] = stubProperties.original;
     }
   }
-};
\ No newline at end of file
+};