Add python 3.7 unit and functional tox jobs

Without these, if you try to run tox -epy37,functional-py37 you'll
get a successful tox run, but no actual tests are run, which is
rather misleading. Given the generaly availability of python 3.7
this is a bad thing.

Running the tests under python 3.7 identified a few minor tests
failures, also fixed here. Each is a result of a change in behavior in
python 3.7:

* printable unicode changes with a new Unicode 11-based unicodedata
  package
* intentionally raising StopIteration in a generator is now considered a
  RuntimeError, 'return' should be used instead
* an exception message is different beween python 3 and python 2, and the
  guard for it was mapping python 3.5 and 3.6 but not 3.7.

zuul configuration is adjusted to add an experimental job for python 3.7
unit. A functional test job is not added, because we don't have 3.6 yet,
and we probably want to get through that first.

Closes-Bug: #1807976
Closes-Bug: #1807970
Change-Id: I37779a12d3b36eb3dc7e2733d07fe0ed23ab3da6

1 files changed, 13 insertions, 0 deletions

diff --git a/tox.ini b/tox.ini
index e3e88f6ab7..d683137857 100644
--- a/tox.ini
+++ b/tox.ini
@@ -52,6 +52,12 @@ basepython = python3.6
 commands =
   {[testenv:py35]commands}
 
+[testenv:py37]
+# TODO(efried): Remove this once https://github.com/tox-dev/tox/issues/425 is fixed.
+basepython = python3.7
+commands =
+  {[testenv:py35]commands}
+
 [testenv:pep8]
 description =
   Run style checks.
@@ -105,6 +111,13 @@ setenv = {[testenv]setenv}
 commands =
   {[testenv:functional]commands}
 
+[testenv:functional-py37]
+basepython = python3.7
+envdir = {toxworkdir}/py37
+setenv = {[testenv]setenv}
+commands =
+  {[testenv:functional]commands}
+
 [testenv:api-samples]
 envdir = {toxworkdir}/shared
 setenv =