zodbtools: Add way to run tests

Following approach used for pygolang in the previous patch lets add
testing support for zodbtools:

- Add zodbtools/buildout-dev.cfg that overrides [zodbtools] to use the
  software from git checkout.

- Add zodbtools/test<X>.cfg that is software-release to create a test
  instance to be run under testnode. To help itself on this task this
  software release uses just-added stack/nxdtest.cfg and
  [python-interpreter] from pygolang, so the code in zodbtools is
  minimal.

Zodbtools can be tested against both ZODB4 and ZODB5 because we still
use ZODB4 as our primary ZODB version, but it is no longer supported by
upstream which considers only ZODB5 as current.

component/zodbtools/buildout-dev.cfg

+# SlapOS component for zodbtools development.
+
+[buildout]
+extends =
+    buildout.cfg
+    ../git/buildout.cfg
+
+# override zodbtools to install it from latest git version
+[zodbtools]
+recipe  = zc.recipe.egg:develop
+setup   = ${zodbtools-repository:location}
+
+[zodbtools-repository]
+recipe  = slapos.recipe.build:gitclone
+repository = https://lab.nexedi.com/nexedi/zodbtools.git
+branch  = master
+location = ${buildout:parts-directory}/zodbtools-dev
+git-executable = ${git:location}/bin/git
+
+
+# unpin zodbtools from versions, so that buildout does not fallback to
+# installing non-dev egg if dev one has changed its version.
+[versions]
+zodbtools =

component/zodbtools/test-common.cfg

+# SlapOS software release to test zodbtools on Nexedi testing infrastructure.
+# Common parts.
+
+[buildout]
+extends =
+# test*.cfg first extend from neoppod/software<ZODB-flabour>.cfg to use
+# appropriate ZODB and versions of other components.
+
+    ../../stack/nxdtest.cfg
+    ../pytest/buildout.cfg
+    buildout-dev.cfg
+
+parts =
+    zodbtools
+
+#   for instance
+    zodbtools-python
+    slapos-cookbook
+    instance.cfg
+
+
+# bin/python is preinstalled with sys.path to zodbtools & friends.
+[zodbtools-python]
+<= python-interpreter
+eggs = zodbtools[test]
+
+# env.sh for zodbtools's python to be on $PATH.
+[zodbtools-env.sh]
+recipe   = slapos.recipe.template:jinja2
+rendered = ${buildout:directory}/${:_buildout_section_name_}
+template = inline:
+  export PS1="(zodbtools-env) $PS1"
+  export PATH=${buildout:bin-directory}:$PATH
+
+# instance to run nxdtest.
+[instance.cfg]
+<= jinja2-template
+template = inline:
+  [buildout]
+  extends = ${nxdtest-instance.cfg:rendered}
+
+  [runTestSuite]
+  env.sh  = ${zodbtools-env.sh:rendered}
+  workdir = ${zodbtools-repository:location}
+
+
+[versions]
+freezegun = 1.0.0

component/zodbtools/test-zodb5.cfg

+# SlapOS software release to test zodbtools/ZODB5 on Nexedi testing infrastructure.
+
+[buildout]
+extends =
+    ../../software/neoppod/software-zodb5.cfg
+    test-common.cfg

component/zodbtools/test.cfg

+# SlapOS software release to test zodbtools on Nexedi testing infrastructure.
+
+[buildout]
+extends =
+    ../../software/neoppod/software.cfg
+    test-common.cfg