Special handling for python doctest code blocks

A doctest code block begins with ">>>" and is not indented.  Identify
these in doxygen comments and treat them accordingly.  Also add check
to padCodeAndVerbatimBlocks for these because Sphinx requires an empty
line before.

Add test case to doxygen_code_blocks.i.

Examples/test-suite/doxygen_code_blocks.i

@@ -46,6 +46,12 @@
  * \code{.py}
  * print('hello world')
  * \endcode
+ *
+ * A python doctest example:
+ * \code{.py}
+ * >>> 1 + 1
+ * 2
+ * \endcode
  */
 int function()
 {

Examples/test-suite/python/doxygen_code_blocks_runme.py

@@ -50,4 +50,9 @@ A code block for python:
 
 .. code-block:: python
 
-    print('hello world')""")
+    print('hello world')
+
+A python doctest example:
+
+>>> 1 + 1
+2""")

Source/Doxygen/pydoc.cxx

@@ -174,7 +174,8 @@ static string padCodeAndVerbatimBlocks(const string &docString) {
     } else {
       if (lastLineWasNonBlank &&
 	  (line.compare(pos, 13, ".. code-block") == 0 ||
-	  line.compare(pos, 7, ".. math") == 0)) {
+	   line.compare(pos, 7, ".. math") == 0 ||
+	   line.compare(pos, 3, ">>>") == 0)) {
 	// Must separate code or math blocks from the previous line
 	result += '\n';
       }
@@ -563,9 +564,6 @@ void PyDocConverter::handleCode(DoxygenEntity &tag, std::string &translatedComme
 
   trimWhitespace(translatedComment);
 
-  // Use the current indent for the code-block line itself.
-  translatedComment += indent.getFirstLineIndent();
-
   // Check for an option given to the code command (e.g. code{.py}),
   // and try to set the code-block language accordingly.
   string option = getCommandOption(tag.typeOfEntity, '{', '}');
@@ -589,14 +587,6 @@ void PyDocConverter::handleCode(DoxygenEntity &tag, std::string &translatedComme
     // limb and assume that the examples in the C or C++ sources use
     // C++.
     codeLanguage = "c++";
-  
-  translatedComment += ".. code-block:: " + codeLanguage + "\n\n";
-
-  // Specify the level of extra indentation that will be used for
-  // subsequent lines within the code block.  Note that the correct
-  // "starting indentation" is already present in the input, so we
-  // only need to add the desired code block indentation.
-  string codeIndent = m_indent;
 
   std::string code;
   handleTagVerbatim(tag, code, arg);
@@ -605,6 +595,27 @@ void PyDocConverter::handleCode(DoxygenEntity &tag, std::string &translatedComme
   // command:
   eraseLeadingNewLine(code);
 
+  // Check for python doctest blocks, and treat them specially:
+  bool isDocTestBlock = false;
+  size_t startPos;
+  // ">>>" would normally appear at the beginning, but doxygen comment
+  // style may have space in front, so skip leading whitespace
+  if ((startPos=code.find_first_not_of(" \t")) != string::npos && code.substr(startPos,3) == ">>>")
+    isDocTestBlock = true;
+
+  string codeIndent;
+  if (! isDocTestBlock) {
+    // Use the current indent for the code-block line itself.
+    translatedComment += indent.getFirstLineIndent();
+    translatedComment += ".. code-block:: " + codeLanguage + "\n\n";
+
+    // Specify the level of extra indentation that will be used for
+    // subsequent lines within the code block.  Note that the correct
+    // "starting indentation" is already present in the input, so we
+    // only need to add the desired code block indentation.
+    codeIndent = m_indent;
+  }
+
   translatedComment += codeIndent;
   for (size_t n = 0; n < code.length(); n++) {
     if (code[n] == '\n') {