Add assertFalse

Author: pyk

src/test.sol

@@ -70,6 +70,20 @@ contract DSTest {
         }
     }
 
+    function assertFalse(bool condition) internal {
+        if (condition) {
+            emit log("Error: Assertion Failed");
+            fail();
+        }
+    }
+
+    function assertFalse(bool condition, string memory err) internal {
+        if (condition) {
+            emit log_named_string("Error", err);
+            assertTrue(condition);
+        }
+    }
+
     function assertEq(address a, address b) internal {
         if (a != b) {
             emit log("Error: a == b not satisfied [address]");