Coerce exposed_ports to string

Closes ansible#1781.

Unfortunately, Cerberus (our schema validation library) is not already
doing this for us. So, we have a bug raised and here is the fix. We're
probably open to numerous version of this bug but let's see when the
reports come in.

Refs:
  * http://docs.python-cerberus.org/en/stable/normalization-rules.html#value-coercion
  * pyeve/cerberus#316

Signed-off-by: Luke Murphy <[email protected]>

molecule/model/schema_v2.py

@@ -25,8 +25,7 @@
 import cerberus
 import cerberus.errors
 
-from molecule import interpolation
-from molecule import util
+from molecule import interpolation, util
 
 
 def coerce_env(env, keep_string, v):
@@ -681,6 +680,7 @@ def pre_validate_base_schema(env, keep_string):
  'type': 'list',
  'schema': {
  'type': 'string',
+ 'coerce': str,
  }
  },
  'published_ports': {

test/unit/model/v2/test_platforms_section.py

@@ -115,6 +115,13 @@ def test_platforms_docker(_config):
  assert {} == schema_v2.validate(_config)
 
 
+@pytest.mark.parametrize(
+ '_config', ['_model_platforms_docker_section_data'], indirect=True)
+def test_platforms_docker_exposed_ports_coerced(_config):
+ _config['platforms'][0]['exposed_ports'] = [9904]
+ assert {} == schema_v2.validate(_config)
+
+
 @pytest.fixture
 def _model_platforms_docker_errors_section_data():
  return {