Add a test for preserve indent.

org_mode_samples/lesser_element/lesser_block/example/preserve_indent.org

@@ -0,0 +1,15 @@
+#+begin_example text -i
+     foo
+#+end_example
+
+#+begin_example text    -n -i
+     foo
+#+end_example
+
+#+begin_example text
+     foo
+#+end_example
+
+#+begin_example text    -n -r -k
+     foo
+#+end_example

org_mode_samples/lesser_element/lesser_block/src/preserve_indent.org

@@ -0,0 +1,15 @@
+#+begin_src text -i
+     foo
+#+end_src
+
+#+begin_src text    -n -i
+     foo
+#+end_src
+
+#+begin_src text
+     foo
+#+end_src
+
+#+begin_src text    -n -r -k
+     foo
+#+end_src