Create documentation for tests

Generate documentation for each test from its docstring.

The sphinx-apidoc tool is used to generate the .rst
files necessary for the generation of the documentation.

When the documentation is being build only functions that
start with "test" are passed to the resulting documentation.

Change-Id: I1878f67e10df9bb1f8289beda8e59a56b5057fe4
diff --git a/tox.ini b/tox.ini
index 0477d6f..031a400 100644
--- a/tox.ini
+++ b/tox.ini
@@ -282,15 +282,31 @@
   -r{toxinidir}/requirements.txt
   -r{toxinidir}/doc/requirements.txt
 commands =
+  sphinx-apidoc -f -o doc/source/tests/compute tempest/api/compute
+  sphinx-apidoc -f -o doc/source/tests/identity tempest/api/identity
+  sphinx-apidoc -f -o doc/source/tests/image tempest/api/image
+  sphinx-apidoc -f -o doc/source/tests/network tempest/api/network
+  sphinx-apidoc -f -o doc/source/tests/object_storage tempest/api/object_storage
+  sphinx-apidoc -f -o doc/source/tests/scenario tempest/scenario
+  sphinx-apidoc -f -o doc/source/tests/volume tempest/api/volume
   rm -rf doc/build
   sphinx-build -W -b html doc/source doc/build/html
-whitelist_externals = rm
+whitelist_externals =
+    rm
 
 [testenv:pdf-docs]
 deps = {[testenv:docs]deps}
 whitelist_externals =
+   rm
    make
 commands =
+   sphinx-apidoc -f -o doc/source/tests/compute tempest/api/compute
+   sphinx-apidoc -f -o doc/source/tests/identity tempest/api/identity
+   sphinx-apidoc -f -o doc/source/tests/image tempest/api/image
+   sphinx-apidoc -f -o doc/source/tests/network tempest/api/network
+   sphinx-apidoc -f -o doc/source/tests/object_storage tempest/api/object_storage
+   sphinx-apidoc -f -o doc/source/tests/scenario tempest/scenario
+   sphinx-apidoc -f -o doc/source/tests/volume tempest/api/volume
    sphinx-build -W -b latex doc/source doc/build/pdf
    make -C doc/build/pdf