Simplify showing colour values in failing unit tests

Use wxColour::GetAsString() instead of reimplementing it in the test.

tests/asserthelper.cpp

@@ -11,35 +11,9 @@
 
 #include "asserthelper.h"
 
-namespace wxTestPrivate
-{
-
-std::ostream& operator<<(std::ostream& os, const ColourChannel& cc)
-{
-    os.width(2);
-    os.fill('0');
-    os << static_cast<int>(cc.m_value);
-    return os;
-}
-
-}
-
 std::ostream& operator<<(std::ostream& os, const wxColour& c)
 {
-    using wxTestPrivate::ColourChannel;
-
-    os << std::hex << std::noshowbase
-       << "("
-       << ColourChannel(c.Red()) << ", "
-       << ColourChannel(c.Green()) << ", "
-       << ColourChannel(c.Blue());
-
-    if ( const unsigned char a = c.Alpha() )
-    {
-        os << ", " << ColourChannel(a);
-    }
-
-    os << ")";
+    os << c.GetAsString(wxC2S_HTML_SYNTAX);
 
     return os;
 }

tests/asserthelper.h

@@ -14,21 +14,6 @@
 #include "wx/gdicmn.h"
 #include "wx/font.h"
 
-namespace wxTestPrivate
-{
-    // by default colour components values are output incorrectly because they
-    // are unsigned chars, define a small helper struct which formats them in
-    // a more useful way
-    struct ColourChannel
-    {
-        ColourChannel(unsigned char value) : m_value(value) { }
-
-        unsigned char m_value;
-    };
-
-    std::ostream& operator<<(std::ostream& os, const ColourChannel& cc);
-} // wxTestPrivate namespace
-
 // Operators used to show the values of the corresponding types when comparing
 // them in the unit tests fails.
 std::ostream& operator<<(std::ostream& os, const wxColour& c);