diff --git a/debpython/version.py b/debpython/version.py
index 544d65ddd40f7419bd4a66e8fa558e84da6ba047..e1ac9a848aed874e8109b7940cbf4105fff0a984 100644
--- a/debpython/version.py
+++ b/debpython/version.py
@@ -41,8 +41,7 @@ _supported = environ.get('DEBPYTHON_SUPPORTED')
 _default = environ.get('DEBPYTHON_DEFAULT')
 if not _supported or not _default:
     _config = SafeConfigParser()
-    _config.read(['/usr/share/python/debian_defaults',
-                 join(dirname(__file__), '..', 'debian', 'debian_defaults')])
+    _config.read('/usr/share/python/debian_defaults')
     if not _default:
         _default = _config.get('DEFAULT', 'default-version')[6:]
     if not _supported:
diff --git a/tests/common.mk b/tests/common.mk
new file mode 100644
index 0000000000000000000000000000000000000000..00cb7261c888f32eccef1e72d235bda309b1817c
--- /dev/null
+++ b/tests/common.mk
@@ -0,0 +1,12 @@
+#!/usr/bin/make -f
+
+export DEBPYTHON_DEFAULT ?= $(shell sed -rne 's,^default-version = python(.*),\1,p' ../../debian/debian_defaults)
+export DEBPYTHON_SUPPORTED ?= $(shell sed -rne '/^supported-versions/{s/^supported-versions = (.*)/\1/g;s/python//g;s/,//g;p}' ../../debian/debian_defaults)
+
+all: run check
+
+run: clean
+	dpkg-buildpackage -b -us -uc
+
+clean-common:
+	./debian/rules clean
diff --git a/tests/t1/Makefile b/tests/t1/Makefile
index f3e1403d88e959253945dc55226c642ce1f2e90d..b66038c95a519b5828e1521cf4c7f9608abdc3f1 100644
--- a/tests/t1/Makefile
+++ b/tests/t1/Makefile
@@ -1,11 +1,7 @@
 #!/usr/bin/make -f
 
-all: run check
-
-DPY=$(shell PYTHONPATH=../../ python -c 'import debpython.version as v; print(v.vrepr(v.DEFAULT))')
-
-run: clean
-	dpkg-buildpackage -b -us -uc
+include ../common.mk
+DPY=$(DEBPYTHON_DEFAULT)
 
 check:
 	grep -q "Depends: .*python-mako" debian/python-foo/DEBIAN/control
@@ -15,6 +11,5 @@ check:
 	[ `readlink debian/python-foo/usr/lib/python$(DPY)/dist-packages/foo/absolute_link_to_tmp` = /tmp ]
 	[ `readlink debian/python-foo/usr/lib/python$(DPY)/dist-packages/foo/link_to_parent_dir` = .. ]
 
-clean:
-	./debian/rules clean
+clean: clean-common
 	rm -rf lib/Foo.egg-info
diff --git a/tests/t2/Makefile b/tests/t2/Makefile
index 3d0226a8773d3eb6a5d0bb545b8beb91495a0048..f46ef1cc79650e3a57b6c61797800250440196ca 100644
--- a/tests/t2/Makefile
+++ b/tests/t2/Makefile
@@ -1,16 +1,10 @@
 #!/usr/bin/make -f
 
-all: run check
-
-
-run: clean
-	dpkg-buildpackage -b -us -uc
+include ../common.mk
+clean: clean-common
 
 check:
 	test -f debian/python-foo/usr/lib/python2.6/dist-packages/foo.py
 	test -f debian/python-foo/usr/lib/python2.6/dist-packages/bar/bar.py
 	grep -q pycompile debian/python-foo/DEBIAN/postinst
 	grep -q pyclean debian/python-foo/DEBIAN/prerm
-
-clean:
-	./debian/rules clean
diff --git a/tests/t3/Makefile b/tests/t3/Makefile
index 2a1727900df4d934167f26344088b230aec4dd9f..21658b4736062f4459c2e898224a9ed3aedcf5c7 100644
--- a/tests/t3/Makefile
+++ b/tests/t3/Makefile
@@ -1,11 +1,7 @@
 #!/usr/bin/make -f
 
-all: run check
-
-DPY=$(shell PYTHONPATH=../../ python -c 'import debpython.version as v; print(v.vrepr(v.DEFAULT))')
-
-run: clean
-	dpkg-buildpackage -b -us -uc
+include ../common.mk
+DPY=$(DEBPYTHON_DEFAULT)
 
 check:
 	grep -q "pycompile -p python-foo /usr/lib/python-foo -V $(DPY)"\
@@ -22,6 +18,5 @@ check:
 	test ! -L debian/python-foo/usr/lib/python${DPY}/dist-packages/foo/quux.so.0
 	test ! -f debian/python-foo/usr/lib/python${DPY}/dist-packages/foo/quux.so.0.0.0
 
-clean:
-	./debian/rules clean
+clean: clean-common
 	rm -rf lib/Foo.egg-info build
diff --git a/tests/t4/Makefile b/tests/t4/Makefile
index 20f4e97b2c4cb8c46956f3ee2cc835ae3c128185..d0ebcb65748b73aeac18492fead38aa1a70249bf 100644
--- a/tests/t4/Makefile
+++ b/tests/t4/Makefile
@@ -1,10 +1,7 @@
 #!/usr/bin/make -f
 
-all: run check
-
-
-run: clean
-	dpkg-buildpackage -b -us -uc
+include ../common.mk
+clean: clean-common
 
 check:
 	grep -q python2.6 debian/foo/usr/share/foo/foo.py
@@ -14,6 +11,3 @@ check:
 	grep -q python2.4 debian/foo/usr/share/foo/baz.py
 	test ! -x debian/foo/usr/share/foo/baz.py
 	grep -q Depends:.*python2.4 debian/foo/DEBIAN/control && false || true
-
-clean:
-	./debian/rules clean
diff --git a/tests/t5/Makefile b/tests/t5/Makefile
index cde00619bc32154e238c89efbdc4d18231e9471c..bac656222f6d902cfc5236e08c91e8ba0bb01171 100644
--- a/tests/t5/Makefile
+++ b/tests/t5/Makefile
@@ -1,10 +1,7 @@
 #!/usr/bin/make -f
 
-all: run check
-
-
-run: clean
-	dpkg-buildpackage -b -us -uc
+include ../common.mk
+clean: clean-common
 
 check:
 	# test dh_python2
@@ -29,6 +26,3 @@ check:
 	do [ `ls debian/python-foo/usr/lib/python2.*/*-packages/$$i/__init__.py 2>/dev/null || true | wc -l` = 0 ];\
 	[ `ls debian/python-foo/usr/lib/python2.*/*-packages/$$i/__init__.pyc 2>/dev/null || true | wc -l` = 0 ];\
 	done
-
-clean:
-	./debian/rules clean
diff --git a/tests/t6/Makefile b/tests/t6/Makefile
index b8f141e9b6eb43282493697d3ba5bea13c961b24..48e3104382883cf621f9ff5a9d7721bfa7e3b118 100644
--- a/tests/t6/Makefile
+++ b/tests/t6/Makefile
@@ -1,10 +1,7 @@
 #!/usr/bin/make -f
 
-all: run check
-
-
-run: clean
-	dpkg-buildpackage -b -us -uc
+include ../common.mk
+clean: clean-common
 
 check:
 	# python2.4 hardcoded via `dh_python2 -V 2.4`
@@ -19,6 +16,3 @@ check:
 	grep -q Depends:.*python2.6 debian/foo/DEBIAN/control
 	grep -q '\-V 2.6 /usr/share/foo' debian/foo/usr/share/python/runtime.d/foo.rtupdate
 	grep -q '/usr/share/foo \-V 2.6' debian/foo/DEBIAN/postinst
-
-clean:
-	./debian/rules clean
diff --git a/tests/t7/Makefile b/tests/t7/Makefile
index a2b7fe8a011ec5351a11045bf09a7cebe4c121f6..2488496549d160aa9f792e37c97acbfb5bc4c1b9 100644
--- a/tests/t7/Makefile
+++ b/tests/t7/Makefile
@@ -1,10 +1,7 @@
 #!/usr/bin/make -f
 
-all: run check
-
-
-run: clean
-	dpkg-buildpackage -b -us -uc
+include ../common.mk
+clean: clean-common
 
 check:
 	# python2.4 hardcoded via `dh_python2 -shebang ...python2.4`
@@ -19,6 +16,3 @@ check:
 	# /local removed from shebang 
 	grep -q '#! /usr/bin/python' debian/foo/usr/share/foo/baz.py
 	grep -q '#! /usr/bin/python2.6' debian/foo/usr/share/foo/foo.py
-
-clean:
-	./debian/rules clean