Adding the following Test Coverage:

Use mysql_user module to create, delete users.
Update user password and ensure new password was updated for the correct user.
Assert user has access to multiple databases
Assert user creation, deleting using different user privilege and ensure privilege work correctly.

test/integration/roles/test_mysql_user/tasks/assert_user.yml

@@ -0,0 +1,34 @@
+# test code to assert mysql user 
+# (c) 2014,  Wayne Rosario <wrosario@ansible.com>
+
+# This file is part of Ansible
+#
+# Ansible is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Ansible is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
+
+# ============================================================
+- name: run command to query for mysql user 
+  command: mysql "-e SELECT User FROM mysql.user where user='{{ user_name }}';"
+  register: result
+
+- name: assert mysql user is present 
+  assert: { that: "'{{ user_name }}' in result.stdout" }
+
+- name: run command to show privileges for user (expect privileges in stdout)
+  command: mysql "-e SHOW GRANTS FOR '{{ user_name }}'@'localhost';"
+  register: result
+  when: priv is defined
+
+- name: assert user has giving privileges 
+  assert: { that: "'GRANT {{priv}} ON *.*' in result.stdout" }
+  when: priv is defined