Implements matcher SizeIs().

include/gmock/gmock-matchers.h

@@ -1972,6 +1972,58 @@ class ResultOfMatcher {
   GTEST_DISALLOW_ASSIGN_(ResultOfMatcher);
 };
 
+// Implements a matcher that checks the size of an STL-style container.
+template <typename SizeMatcher>
+class SizeIsMatcher {
+ public:
+  explicit SizeIsMatcher(const SizeMatcher& size_matcher)
+       : size_matcher_(size_matcher) {
+  }
+
+  template <typename Container>
+  operator Matcher<Container>() const {
+    return MakeMatcher(new Impl<Container>(size_matcher_));
+  }
+
+  template <typename Container>
+  class Impl : public MatcherInterface<Container> {
+   public:
+    typedef internal::StlContainerView<
+         GTEST_REMOVE_REFERENCE_AND_CONST_(Container)> ContainerView;
+    typedef typename ContainerView::type::size_type SizeType;
+    explicit Impl(const SizeMatcher& size_matcher)
+        : size_matcher_(MatcherCast<SizeType>(size_matcher)) {}
+
+    virtual void DescribeTo(::std::ostream* os) const {
+      *os << "size ";
+      size_matcher_.DescribeTo(os);
+    }
+    virtual void DescribeNegationTo(::std::ostream* os) const {
+      *os << "size ";
+      size_matcher_.DescribeNegationTo(os);
+    }
+
+    virtual bool MatchAndExplain(Container container,
+                                 MatchResultListener* listener) const {
+      SizeType size = container.size();
+      StringMatchResultListener size_listener;
+      const bool result = size_matcher_.MatchAndExplain(size, &size_listener);
+      *listener
+          << "whose size " << size << (result ? " matches" : " doesn't match");
+      PrintIfNotEmpty(size_listener.str(), listener->stream());
+      return result;
+    }
+
+   private:
+    const Matcher<SizeType> size_matcher_;
+    GTEST_DISALLOW_ASSIGN_(Impl);
+  };
+
+ private:
+  const SizeMatcher size_matcher_;
+  GTEST_DISALLOW_ASSIGN_(SizeIsMatcher);
+};
+
 // Implements an equality matcher for any STL-style container whose elements
 // support ==. This matcher is like Eq(), but its failure explanations provide
 // more detailed information that is useful when the container is used as a set.
@@ -3079,6 +3131,18 @@ Truly(Predicate pred) {
   return MakePolymorphicMatcher(internal::TrulyMatcher<Predicate>(pred));
 }
 
+// Returns a matcher that matches the container size. The container must
+// support both size() and size_type which all STL-like containers provide.
+// Note that the parameter 'size' can be a value of type size_type as well as
+// matcher. For instance:
+//   EXPECT_THAT(container, SizeIs(2));     // Checks container has 2 elements.
+//   EXPECT_THAT(container, SizeIs(Le(2));  // Checks container has at most 2.
+template <typename SizeMatcher>
+inline internal::SizeIsMatcher<SizeMatcher>
+SizeIs(const SizeMatcher& size_matcher) {
+  return internal::SizeIsMatcher<SizeMatcher>(size_matcher);
+}
+
 // Returns a matcher that matches an equal container.
 // This matcher behaves like Eq(), but in the event of mismatch lists the
 // values that are included in one container but not the other. (Duplicate