custom tostring formatter to CPPUNIT_ASSERT_MESSAGE

Provide an extension trait message_to_string that allows client code
to call ASSERT_MESSAGE with their own string types.

Also provide a default extension trait that accepts std::ostream
messages.

Change-Id: I516f97063c34d86bc91c40e0ec147d5393e7b6ea

2 files changed, 32 insertions, 0 deletions

diff --git a/examples/cppunittest/MessageTest.cpp b/examples/cppunittest/MessageTest.cpp
index c59544d..c0674b8 100644
--- a/examples/cppunittest/MessageTest.cpp
+++ b/examples/cppunittest/MessageTest.cpp
@@ -232,3 +232,30 @@ MessageTest::testNotEqual()
   CPPUNIT_ASSERT( message1 != message2 );
   CPPUNIT_ASSERT( !(message1 != message1) );
 }
+
+
+struct Foo
+{
+    std::string s;
+};
+CPPUNIT_NS_BEGIN
+static std::string message_to_string(const Foo& m)
+{
+    return m.s;
+}
+CPPUNIT_NS_END
+
+void
+MessageTest::testCustomMessageType()
+{
+  Foo foo { "xxxx" };
+  CPPUNIT_ASSERT_MESSAGE( foo, true );
+}
+
+void
+MessageTest::testOStreamMessage()
+{
+  std::ostringstream ost;
+  ost << "xxx" << "yyy";
+  CPPUNIT_ASSERT_MESSAGE( ost, true );
+}
diff --git a/examples/cppunittest/MessageTest.h b/examples/cppunittest/MessageTest.h
index 4c757e8..6fc2237 100644
--- a/examples/cppunittest/MessageTest.h
+++ b/examples/cppunittest/MessageTest.h
@@ -28,6 +28,8 @@ class MessageTest : public CPPUNIT_NS::TestFixture
   CPPUNIT_TEST( testDetailsSome );
   CPPUNIT_TEST( testEqual );
   CPPUNIT_TEST( testNotEqual );
+  CPPUNIT_TEST( testCustomMessageType );
+  CPPUNIT_TEST( testOStreamMessage );
   CPPUNIT_TEST_SUITE_END();
 
 public:
@@ -60,6 +62,9 @@ public:
   void testEqual();
   void testNotEqual();
 
+  void testCustomMessageType();
+  void testOStreamMessage();
+
 private:
   /// Prevents the use of the copy constructor.
   MessageTest( const MessageTest &other );