fix for change by(0) bug

- Closes #17.
rspec · Sep 23, 2010 · fa4446d · fa4446d
1 parent 311ba91
commit fa4446d
Show file tree

Hide file tree

Showing 2 changed files with 7 additions and 2 deletions.
diff --git a/lib/rspec/matchers/change.rb b/lib/rspec/matchers/change.rb
@@ -16,8 +16,9 @@ def matches?(event_proc)
         @before = evaluate_value_proc
         event_proc.call
         @after = evaluate_value_proc
-
+
-        changed? && matches_before? && matches_after? && matches_amount? && matches_min? && matches_max?
+        changed_if_expected = @amount == 0 || changed?
+        changed_if_expected && matches_before? && matches_after? && matches_amount? && matches_min? && matches_max?
       end
 
       def raise_block_syntax_error

diff --git a/spec/rspec/matchers/change_spec.rb b/spec/rspec/matchers/change_spec.rb
@@ -123,6 +123,10 @@ class SomethingExpected
     expect { @instance.some_value += 1 }.to change(@instance, :some_value).by(1)
   end
 
+  it "passes when attribute is not changed and expected amount is 0" do
+    expect { @instance.some_value += 0 }.to change(@instance, :some_value).by(0)
+  end
+
   it "fails when the attribute is changed by unexpected amount" do
     expect do
       expect { @instance.some_value += 2 }.to change(@instance, :some_value).by(1)