Fix the handling of modulemd files with unicode characters.

This commit introduces new to_text_type helper method and calls it
for return value of all mmd.dumps() calls. That way, we always
end up with proper unicode string represntation on both python
major versions.

This commit also adds unicode character to description of all
the yaml files we use in the tests so we can be sure MBS can
handle unicode characters properly.

This might be temporary fix, depending on the result of discussion
at https://github.com/fedora-modularity/libmodulemd/issues/184.

tests/__init__.py

@@ -26,6 +26,7 @@ from mock import patch
 import time
 import hashlib
 from traceback import extract_stack
+from module_build_service.utils import to_text_type
 
 import koji
 import module_build_service
@@ -54,7 +55,7 @@ def read_staged_data(yaml_name):
     if not os.path.exists(filename):
         raise ValueError('Staged data {}.yaml does not exist.'.format(yaml_name))
     with open(filename, 'r') as mmd:
-        return mmd.read()
+        return to_text_type(mmd.read())
 
 
 def patch_config():
@@ -153,8 +154,7 @@ def _populate_data(session, data_size=10, contexts=False):
                 build_one.ref_build_context = unique_hash
                 combined_hashes = '{0}:{1}'.format(unique_hash, unique_hash)
                 build_one.context = hashlib.sha1(combined_hashes.encode("utf-8")).hexdigest()[:8]
-            with open(os.path.join(base_dir, "staged_data", "nginx_mmd.yaml")) as mmd:
-                build_one.modulemd = mmd.read()
+            build_one.modulemd = read_staged_data('nginx_mmd')
             build_one.koji_tag = 'module-nginx-1.2'
             build_one.scmurl = ('git://pkgs.domain.local/modules/nginx?'
                                 '#ba95886c7a443b36a9ce31abda1f9bef22f2f8c9')
@@ -343,7 +343,7 @@ def scheduler_init_data(tangerine_state=None):
     build_one.time_submitted = datetime(2017, 2, 15, 16, 8, 18)
     build_one.time_modified = datetime(2017, 2, 15, 16, 19, 35)
     build_one.rebuild_strategy = 'changed-and-after'
-    build_one.modulemd = mmd.dumps()
+    build_one.modulemd = to_text_type(mmd.dumps())
     build_one_component_release = get_rpm_release(build_one)
     build_one.buildrequires.append(platform_br)
 
@@ -456,7 +456,7 @@ def reuse_component_init_data():
     xmd['mbs']['scmurl'] = build_one.scmurl
     xmd['mbs']['commit'] = 'ff1ea79fc952143efeed1851aa0aa006559239ba'
     mmd.set_xmd(glib.dict_values(xmd))
-    build_one.modulemd = mmd.dumps()
+    build_one.modulemd = to_text_type(mmd.dumps())
     build_one.buildrequires.append(platform_br)
 
     component_one_build_one = module_build_service.models.ComponentBuild()
@@ -541,7 +541,7 @@ def reuse_component_init_data():
     xmd['mbs']['scmurl'] = build_one.scmurl
     xmd['mbs']['commit'] = '55f4a0a2e6cc255c88712a905157ab39315b8fd8'
     mmd.set_xmd(glib.dict_values(xmd))
-    build_two.modulemd = mmd.dumps()
+    build_two.modulemd = to_text_type(mmd.dumps())
     build_two.buildrequires.append(platform_br)
 
     component_one_build_two = module_build_service.models.ComponentBuild()
@@ -620,7 +620,7 @@ def reuse_shared_userspace_init_data():
         build_one.build_context = 'e046b867a400a06a3571f3c71142d497895fefbe'
         build_one.runtime_context = '50dd3eb5dde600d072e45d4120e1548ce66bc94a'
         build_one.state = BUILD_STATES['ready']
-        build_one.modulemd = mmd.dumps()
+        build_one.modulemd = to_text_type(mmd.dumps())
         build_one.koji_tag = 'module-shared-userspace-f26-20170601141014-75f92abb'
         build_one.scmurl = ('https://src.stg.fedoraproject.org/modules/testmodule.'
                             'git?#7fea453')
@@ -671,7 +671,7 @@ def reuse_shared_userspace_init_data():
         build_one.build_context = 'e046b867a400a06a3571f3c71142d497895fefbe'
         build_one.runtime_context = '50dd3eb5dde600d072e45d4120e1548ce66bc94a'
         build_one.state = BUILD_STATES['done']
-        build_one.modulemd = mmd2.dumps()
+        build_one.modulemd = to_text_type(mmd2.dumps())
         build_one.koji_tag = 'module-shared-userspace-f26-20170605091544-75f92abb'
         build_one.scmurl = ('https://src.stg.fedoraproject.org/modules/testmodule.'
                             'git?#7fea453')
@@ -741,7 +741,8 @@ def make_module(nsvc, requires_list=None, build_requires_list=None, base_module=
     mmd.set_version(int(version))
     mmd.set_context(context)
     mmd.set_summary("foo")
-    mmd.set_description("foo")
+    # Test unicode in mmd.
+    mmd.set_description(u"foo \u2019s")
     licenses = Modulemd.SimpleSet()
     licenses.add("GPL")
     mmd.set_module_licenses(licenses)
@@ -802,7 +803,7 @@ def make_module(nsvc, requires_list=None, build_requires_list=None, base_module=
     module_build.build_context = context
     module_build.stream_build_context = context
     module_build.runtime_context = context
-    module_build.modulemd = mmd.dumps()
+    module_build.modulemd = to_text_type(mmd.dumps())
     if base_module:
         module_build.buildrequires.append(base_module)
     if 'koji_tag' in xmd['mbs']: