Complete test suite overhaul.

* rename a few test modules to make the names more consistent

* do not copy/use Sphinx from build/ (unnecessary without 2to3)

* use a temporary dir for *all* test projects, the source tree
  will stay pristine that way  (default is tests/build)

* speed up tests by ~3x by splitting up test projects and avoiding
  rebuilds

tests/roots/test-directive-code/dedent.rst

@@ -1,22 +1,35 @@
 Dedent
 ======
 
-Code blocks
------------
-
-.. code-block:: ruby
-   :linenos:
-   :dedent: 4
-
-       def ruby?
-           false
-       end
-
-
 Literal Include
 ---------------
 
+.. literalinclude:: literal.inc
+   :language: python
+   :lines: 10-11
+   :dedent: 0
+
+.. literalinclude:: literal.inc
+   :language: python
+   :lines: 10-11
+   :dedent: 1
+
+.. literalinclude:: literal.inc
+   :language: python
+   :lines: 10-11
+   :dedent: 2
+
+.. literalinclude:: literal.inc
+   :language: python
+   :lines: 10-11
+   :dedent: 3
+
 .. literalinclude:: literal.inc
    :language: python
    :lines: 10-11
    :dedent: 4
+
+.. literalinclude:: literal.inc
+   :language: python
+   :lines: 10-11
+   :dedent: 1000

tests/roots/test-directive-code/dedent_code.rst

@@ -0,0 +1,53 @@
+Dedent
+======
+
+Code blocks
+-----------
+
+.. code-block:: ruby
+   :linenos:
+   :dedent: 0
+
+       def ruby?
+           false
+       end
+
+.. code-block:: ruby
+   :linenos:
+   :dedent: 1
+
+       def ruby?
+           false
+       end
+
+.. code-block:: ruby
+   :linenos:
+   :dedent: 2
+
+       def ruby?
+           false
+       end
+
+.. code-block:: ruby
+   :linenos:
+   :dedent: 3
+
+       def ruby?
+           false
+       end
+
+.. code-block:: ruby
+   :linenos:
+   :dedent: 4
+
+       def ruby?
+           false
+       end
+
+.. code-block:: ruby
+   :linenos:
+   :dedent: 1000
+
+       def ruby?
+           false
+       end