Unbreak wendelin.core and pygolang tests

Hello up there.

I've noticed that wendelin.core tests became failing to build and
automatically disabled some time ago. Not good. I've tried to fix build
failures. Please see individual patches for details.

/cc @levin.zimmermann
/reviewed-by @jerome
/reviewed-on !1492

component/ZEO/buildout.cfg

@@ -48,6 +48,7 @@ recipe  = zc.recipe.egg:develop
 setup   = ${ZEO4-repository:location}
 egg     = ZEO
 egg-versions =
+  ZEO = 4.3.1
 
 [ZEO4-repository]
 recipe  = slapos.recipe.build:gitclone

component/pygolang/test.cfg

@@ -18,8 +18,10 @@ parts =
 
 
 # tune pygolang to install with all and for-tests extras.
+# list all_test-dependent eggs that must come through in-tree recipes.
 [pygolang]
 egg = pygolang[all_test]
+depends += ${numpy:egg}
 
 # bin/python is preinstalled with sys.path to pygolang & friends.
 [pygolang-python]

component/wendelin.core/test-common.cfg

@@ -3,8 +3,8 @@
 
 [buildout]
 extends =
-# test*.cfg first extend from neoppod/software<ZODB-flavour>.cfg to use
-# appropriate ZODB and versions of other components.
+    ../../stack/erp5/buildout.cfg
+    ../../software/neoppod/software.cfg
 
     ../pytest/buildout.cfg
     ../scipy/buildout.cfg

component/wendelin.core/test-zodb4-wc2.cfg

 # SlapOS software release to test wendelin.core/ZODB4-wc2 on Nexedi testing infrastructure.
 
 [buildout]
-extends = test.cfg
+extends = test-common.cfg
 
 [ZODB]
 major = 4-wc2

component/wendelin.core/test-zodb5.cfg

 # SlapOS software release to test wendelin.core/ZODB5 on Nexedi testing infrastructure.
 
 [buildout]
-extends =
-    ../../stack/erp5/buildout.cfg
-    ../../software/neoppod/software-zodb5.cfg
-    test-common.cfg
+extends = test-common.cfg
+
+[ZODB]
+major = 5
+
+
+# ZEO[test] needs ZopeUndo
+[versions]
+ZopeUndo = 5.0

component/wendelin.core/test.cfg

-# SlapOS software release to test wendelin.core on Nexedi testing infrastructure.
-
-[buildout]
-extends =
-    ../../stack/erp5/buildout.cfg
-    ../../software/neoppod/software.cfg
-    test-common.cfg