Completed commodity math tests.

1 files changed, 11 insertions, 1 deletions

diff --git a/amount.cc b/amount.cc
index 73bc6718..4e0e2185 100644
--- a/amount.cc
+++ b/amount.cc
@@ -635,11 +635,21 @@ amount_t& amount_t::operator/=(const amount_t& amt)
   }
 
   if (has_commodity() && amt.has_commodity() &&
-      commodity() != amt.commodity())
+      commodity() != amt.commodity()) {
     throw new amount_error
       (std::string("Dividing amounts with different commodities: ") +
        (has_commodity() ? commodity_->qualified_symbol : "NONE") + " != " +
        (amt.has_commodity() ? amt.commodity_->qualified_symbol : "NONE"));
+  }
+
+  if (! amt.quantity || ! amt) {
+    throw new amount_error("Divide by zero");
+  }
+  else if (! quantity) {
+    *this = amt;
+    *this = *this - *this;	// preserve the foreign commodity
+    goto finish;
+  }
 
   _dup();