diff --git a/gnu/packages/python-xyz.scm b/gnu/packages/python-xyz.scm
index ba00670459..e5f7808baf 100644
--- a/gnu/packages/python-xyz.scm
+++ b/gnu/packages/python-xyz.scm
@@ -7196,6 +7196,8 @@ (define-public python2-backports-shutil-get-terminal-size
        (modify-phases %standard-phases
          (replace 'check
            (lambda _
+             (setenv "PYTHONPATH" (string-append "./build/lib:"
+                                                 (getenv "PYTHONPATH")))
              (invoke "py.test" "-v"))))))
     (native-inputs
      `(("python2-pytest" ,python2-pytest)))